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Repairs in general

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Anonymous
April 26, 2005 6:27:55 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Hi Guys,

i have been arcade collecting for about a year now and i have decided
to get into repair... i recently splashed out and got a 32 channel
analyzer, a fluke scope and a kick arse soldering station with the hope
of reparing some of my "unknown condition" ebay bargins (bargins for a
reason).

i had a shot at it a few times, trying to repair some dead galaxians
and a dead pacmans... but couldnt work it out on my own. read the
repair guides, 3 or 4 times over for both games and not a whole lot of
help.

so guys, i'm looking for a vetran who might be interested in teaching a
repair newbie. I'm located in singapore (i'm aussie) and looking to
learn from a guy who is a little switched on, i checked locally to find
someone to teach me in aus, but this is a real dieing trade. I'm happy
to pay someone to help me out and hell, i'll send you a web cam so we
can communicate (love the internet).

is there anyone out there interested in maybe mentoring me a little, to
get me started in the basics of repair? promise i wont pester you with
massive long complicated emails... and hell, i'll even paypal you some
cash for your time.

let me know if anyone is intersted.

-nat

More about : repairs general

Anonymous
April 26, 2005 8:15:34 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

I my opinion before you can start debugging embedded systems (which is
what an arcade game realy is) you have to get familiar with them first.
Now you don't have to go nutz and get a degree in this stuff (although
it helps :-) ) but you should understand the basics. Even beyong
schematics you should know:
- Digital logic (logic gates, latches, memory, ...what they do and how
they work)
- Embedded system basics (how to acess ROM, RAM..what a microprocessor
does)
- Debugging techniques (most important in my opinion.. once a symptom
is found, how do I go about findingthe source of the problem?)

Probing a board won't tell you anything unless you can read the
schematics to understand the layout of the hardware, and then
understand how the whole thing works (or in this case... is supposed to
work) :-)
No I went to college for this but I'm sure there are ample book out
there that teach this stuff too. I had considered teaching a web
course on the subject and people who were interested could just
download the free lectures. Now that graduate school is over 4 me .. I
just may do that. :-)

Fell free to email w/questions...
-Adam Courchesne
ajcrm125@gmail.com
www.onecircuit.com
Anonymous
April 26, 2005 10:08:08 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Yes but a logic analyzer won't tell you anything if:
A) you don't know what you're looking at
B) you don't know what you're looking for
Related resources
Anonymous
April 26, 2005 11:21:03 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Whoops. my bad.
Anonymous
April 26, 2005 11:46:59 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Nathan, Phil,

My best advice is to get on the web and begin reading as much as you
can about the basics, digital electronics, transistors, passive
components (capacitors, resistors, etc), how embedded systems
(microprocessors) are put together, Ohm's Law, and get a good
foundation for understanding what you're about to repair. I think a
good litmus test to know if you're ready is to be able to pick up any
given data sheet on any common part (74xx series) and be able to
understand 85-90% of what the data sheet says. Take a minute and go to
www.ti.com and search for part 74ls74. Download the data sheet and take
a quick look at the kinds of things to understand, and then Google
search from there. Once you understand what the components are doing,
then move on to learning how to read schematics and how the components
work together.

Once you understand the basics, then learn about 'tricks' (not
shortcuts) for repairing pcbs. (Maybe 'techniques' is a better word
there.) Best place to start there is Randy Fromm's Secret Tech Server.
Also Google on RGVAC for specific problems, and as always you can ask
us specific questions. :-)

Here are a few links to get you started:

www.play-hookey.com
http://slot-tech-ftp.serveftp.com:8080/technical_depart...
http://www.starbase74.com/mame/solderframe.htm
http://www.elexp.com/tips.htm
http://artfromny.com/testing_transistors.htm :-)
http://www.eastaughs.fsnet.co.uk/tutorial/cpu/index.htm

Learning how to troubleshoot and repair pcbs doesn't happen overnight,
but once you have the basics down and have some experience it can be
very rewarding!

Good luck!

- Craig
Anonymous
April 26, 2005 12:04:37 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Guys, i'm in the same boat as phil. I'm a network engineer by trade.
i know how to read a schematic, i know how to what ram/rom/proc does
and i also know what logic gates are and how they work.

what i lack is being able to look at a galaxian board that gives junk
on the screen, know where that problem is being caused (is it ram? or
is it in the data path somewhere?) where to find the "rough" area to
look. At the moment, i sit down with my logic analyzer, hook up the
clips to all legs on 8080 and see whats giving me either a constant 0.
If all legs are buzzing, then i used my probe to poke around the board.
If most of the chips are buzzing, than i have 0 idea what to do next.

What i need is someone to bounce questions off. I've tried it before in
this NG and all i get is "replace ram/rom/cpu/74LS245's"... which is
not very helpful... i belive this is called "shot gun" ;P...

I dont mind doing the reading, if i get some decent books... i've tried
the randy from stuff and its actually not very good. It jumps from
being basic circuit stuff to "and thats how to fix a board" with no
real actual troubleshooting demo's in the middle.

again, more keen to speak with someone to get the basics of what to
look for.. not nessisarily how each component works individually... but
how to break the system up into troubleshootable bits.

-nat
Anonymous
April 26, 2005 12:18:42 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Hi Nat,
Unfortunatley I am In Chicago or I would welcome your help. I haved so
much repair work at this time it is not funny.

You might want to pickup a few basic tools that will help you to fix
boards and other game problems.
Besides the Basic Tools.

Here's a List

1: Logic probe
2: Analog MultiMeter
3: Digital Multi with a Diode Check
4: Degause coil
5: Solder /Desolder Station
6: Magnifier w/lamp
7: Ascorted Chip Pullers
8: Solder Wick
9: Good Scope. Dual Trace with memory store is perfered.
10: ISOLATION TRANSFORMER For your test equipment to plug into
Very important when you start probing around Monitor boards.
11: Dental Picks. Insulate one for use as a probe when you start to
look for damaged traces.
12: Plastic TV Alignment Tools
13: In Line Transistor Checker
14: RGB Patter Generator
15: ESR CAP Checker
16: Bag of Asorted Clip Leads
17: Dremel Tool for cutting the pins on IC's
18: Assorted IC Sockets.
19: Logic Cheat Sheet. AND,OR,NAN gate logic sheet.
20: 26 to 28 gauge wire for repairing damaged traces.
21: Electron Micro Scope for Trace repair.
22: Tube Rejuvenator One of my Favorites
23: Burnishing tools
24: Scotch Brigths.
25: Old Tooth Brush and Isopropa Alchol to clean up the flux.
26: Hot Air Solder Station for SMD(Service Mount Device) reair.
27: Very Very Fine Solder.
28: Silver Solder for the Hi Heat Area's.
29: High Voltage Probe
30: Data Book on IC's or Wireless Laptop with Internet for Research. So
you can pull up Data Sheets on the IC's you are probing.

A good Stock of IC's. Otherwise all your time for repair is now sitting
on a shelf waiting for a part that you replace then find another part
that you need to off to the internet to reporder and waite

It is at the point were I will work on the outside problems on a board.
The Buffer chips that are used to interface stuff like Player 1 and 2
Buttons,Power issues, Damaged Traces
Beyond that I send my boards out for repair. It is cheaper in the long
run and I can utilize my time fixing something else. There are enough
Tech's out there that have been doing board repairs for so long they
can find the problem with there eye's closed as they pass there hands
across the board.
If you do a search you will find some good info on the particular board
you wish to reair.

Still want to Play Boards :) 

Have Fun

J & R
April 26, 2005 1:43:38 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

About the same story here... Would really like to get into PCB repairs, but
not much information available that goes beyond "check eproms & reseat
socketed IC's"...

Haven't got that 32 channel analyzer & fluke scope either :-(

I was also looking for the repair logs but the ftp site for this group seems
to be unavailable.

Hopefully someone will get back on this...


"_NathanK_" <nkulinitsch@gmail.com> wrote in message
news:1114507675.438311.85630@f14g2000cwb.googlegroups.com...
> Hi Guys,
>
> i have been arcade collecting for about a year now and i have decided
> to get into repair... i recently splashed out and got a 32 channel
> analyzer, a fluke scope and a kick arse soldering station with the hope
> of reparing some of my "unknown condition" ebay bargins (bargins for a
> reason).
>
> i had a shot at it a few times, trying to repair some dead galaxians
> and a dead pacmans... but couldnt work it out on my own. read the
> repair guides, 3 or 4 times over for both games and not a whole lot of
> help.
>
> so guys, i'm looking for a vetran who might be interested in teaching a
> repair newbie. I'm located in singapore (i'm aussie) and looking to
> learn from a guy who is a little switched on, i checked locally to find
> someone to teach me in aus, but this is a real dieing trade. I'm happy
> to pay someone to help me out and hell, i'll send you a web cam so we
> can communicate (love the internet).
>
> is there anyone out there interested in maybe mentoring me a little, to
> get me started in the basics of repair? promise i wont pester you with
> massive long complicated emails... and hell, i'll even paypal you some
> cash for your time.
>
> let me know if anyone is intersted.
>
> -nat
>
Anonymous
April 26, 2005 2:20:19 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

> 21: Electron Micro Scope for Trace repair.

!!!

You're not repairing molecules are you? ;-) A 10x-50x scope is good
for surface mount and fine pitch stuff - that's mostly 1990's and later
boards. The rest of the list is fairly comprehensive. One thing I wold
add is a good regulated benchtop power supply. A variable supply 0V to
30V @ 5A is ideal.

- Craig
Anonymous
April 26, 2005 2:25:23 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Nathan,

Sounds like you need to speak with someone who's repaired a few
Galaxian boards. I did one a while back. The invaders were missing red,
and were black and two other colors. Turns out the PROM driving the D/A
resistors was bad. Couldn't find any of those PROMs to burn, so I
replaced the particular 'red' resistor with a lower value. Half-assed,
but it did work! ;-)

Try www.elektronforge.com ?

- Craig
Anonymous
April 26, 2005 2:38:48 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Anytime! ;-)

Sure would be cool if there were a Spies-type site dedicated to repair
logs. Most of the repair logs I've seen have been on individual's
websites, and if detailed, are dedicated to one game. Try:

http://coinop.org/repair/index.aspx

....or:

http://www.ionpool.net/

- Craig
Anonymous
April 26, 2005 2:42:43 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

> 21: Electron Micro Scope for Trace repair.

My Bad Phil.
I Have . A Micro Scope With a External Light Source Ring. Not an
Electron Micro Scope.
Spaced a Bit. Thought it is great for removing Slivers. :) 

I Picked Up My Micro Scope From a Cellular Repair place that was going
out of business. For $200
It has a Light Ring that sits around the lower lens and is coupled to a
external/variable halogen light source.

Alot of the boards I find that come from Ebay not only have Component
Failure but have there traces damaged from major miss handling over the
years.
Anonymous
April 26, 2005 3:04:28 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Anytime! ;-)

Sure would be cool if there was a Spies site dedicated to repair logs.
Most repair logs I've seen have been on individual's webpages, and if
detailed, then usually specific to one game. Try:

http://coinop.org/repair/index.aspx

....or maybe:

http://www.ionpool.net/

- Craig
April 26, 2005 5:31:42 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

As I am also interested in this repair stuff some questions/remarks:

(1) I will see if I can get ahold of a cheap logic probe on eBay. Although I
have no idea how to use it yet one day it may prove useful. I do understand
that it kind of visualizes the data signals (<0.8v = 0; > 2.4v = 1) if a
line is always 0 or 1 it might indicate a possible failure (although not
necessarely it is to be considered one).

(2) I was surprised about the remarks with respect to reading the
schematics. I thought for most of these pcb's schematics are hard to find
and you are kind of supposed to work it out on your own.

(3) Are there any sites/references/books you can suggest regarding the stuff
you think one should have knowledge about before looking at the actual pcb
boards. I am a software programmer myself (btw good luck with that OpenGL
programming) and I do know how some of these things (are supposed to) work
from a users point of view... A lot of the beginners stuff seems to focus on
creating your own pcb experiments which is of little or no interest to me.
Any idea where I should look for a "speed course" ? I've been reading quite
a bit about resistors, transistors, capacitors and more stuff like that and
have a basic idea what they do on their own. When you put them on a full
blown pcb board it doesnt make that much sense anymore though (although
filtering out spikes etc seems to make sense to me). Anyway these boards are
full of IC's (especially 74XX logic), some ROM and RAM chips and a few
microprocessors (Z80/MC68000) and not too many of those single components
the electronics courses I found on the net seem to focus on...

(4) At this moment I am looking at a pcb board which seems to have dynamic
"noise" in its background. I don't think it is a rom problem (as the data is
not wrong, there is just noise on a per 8x8 tile basis) but don't know how
to solve it. Actually I think something is broking in the video circuitry
(ram chip ? how do I even find the video circuitry on the board ?) but have
no idea how to isolate/deduct the problem. I don't have any spare rams
available at the moment (is piggy backing just putting the same chip on top
of the on board chip ?) so it is hard to test. If the problem is in one of
the logic chips I have no idea where to start looking (I suppose this is the
point where the logic probe comes into play).

Thanks for your comments

Phil

"ajcrm125" <ajcrm125@gmail.com> wrote in message
news:1114514134.922917.58010@o13g2000cwo.googlegroups.com...
>I my opinion before you can start debugging embedded systems (which is
> what an arcade game realy is) you have to get familiar with them first.
> Now you don't have to go nutz and get a degree in this stuff (although
> it helps :-) ) but you should understand the basics. Even beyong
> schematics you should know:
> - Digital logic (logic gates, latches, memory, ...what they do and how
> they work)
> - Embedded system basics (how to acess ROM, RAM..what a microprocessor
> does)
> - Debugging techniques (most important in my opinion.. once a symptom
> is found, how do I go about findingthe source of the problem?)
>
> Probing a board won't tell you anything unless you can read the
> schematics to understand the layout of the hardware, and then
> understand how the whole thing works (or in this case... is supposed to
> work) :-)
> No I went to college for this but I'm sure there are ample book out
> there that teach this stuff too. I had considered teaching a web
> course on the subject and people who were interested could just
> download the free lectures. Now that graduate school is over 4 me .. I
> just may do that. :-)
>
> Fell free to email w/questions...
> -Adam Courchesne
> ajcrm125@gmail.com
> www.onecircuit.com
>
Anonymous
April 26, 2005 5:47:12 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Yes... but if he has a logic analyzer the he doesn't need to buy a logic
probe (which is a downgrade), which is what I was responding to...

"ajcrm125" <ajcrm125@gmail.com> wrote in message
news:1114520888.475563.166280@z14g2000cwz.googlegroups.com...
> Yes but a logic analyzer won't tell you anything if:
> A) you don't know what you're looking at
> B) you don't know what you're looking for
>
April 26, 2005 7:24:27 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Craig,

Thank you very much for the information. Your comments are most helpful.

It is getting pretty clear that I should put those pcb's aside for a while
and concentrate on all of the basic electronics first. Once I understand how
the logic circuits are doing their magic I should start asking for
"techniques" as how to track down a specific error in any of the circuits.

Is there an ftp site carrying the archive of the "repair logs" that have
been posted here ?

I've always been intrigued by electronics and so I do not expect to learn it
"overnight"... Some insight from the pro's is definately most welcome
though... So I know what areas to focus on and which ones not...

Best regards,

Filip

"Craig Yarbrough" <hyarbr01@harris.com> wrote in message
news:1114526819.322260.130190@g14g2000cwa.googlegroups.com...
> Nathan, Phil,
>
> My best advice is to get on the web and begin reading as much as you
> can about the basics, digital electronics, transistors, passive
> components (capacitors, resistors, etc), how embedded systems
> (microprocessors) are put together, Ohm's Law, and get a good
> foundation for understanding what you're about to repair. I think a
> good litmus test to know if you're ready is to be able to pick up any
> given data sheet on any common part (74xx series) and be able to
> understand 85-90% of what the data sheet says. Take a minute and go to
> www.ti.com and search for part 74ls74. Download the data sheet and take
> a quick look at the kinds of things to understand, and then Google
> search from there. Once you understand what the components are doing,
> then move on to learning how to read schematics and how the components
> work together.
>
> Once you understand the basics, then learn about 'tricks' (not
> shortcuts) for repairing pcbs. (Maybe 'techniques' is a better word
> there.) Best place to start there is Randy Fromm's Secret Tech Server.
> Also Google on RGVAC for specific problems, and as always you can ask
> us specific questions. :-)
>
> Here are a few links to get you started:
>
> www.play-hookey.com
> http://slot-tech-ftp.serveftp.com:8080/technical_depart...
> http://www.starbase74.com/mame/solderframe.htm
> http://www.elexp.com/tips.htm
> http://artfromny.com/testing_transistors.htm :-)
> http://www.eastaughs.fsnet.co.uk/tutorial/cpu/index.htm
>
> Learning how to troubleshoot and repair pcbs doesn't happen overnight,
> but once you have the basics down and have some experience it can be
> very rewarding!
>
> Good luck!
>
> - Craig
>
Anonymous
April 26, 2005 7:33:30 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

In article <1114507675.438311.85630@f14g2000cwb.googlegroups.com>,
_NathanK_ <nkulinitsch@gmail.com> wrote:
>so guys, i'm looking for a vetran who might be interested in teaching a
>repair newbie. I'm located in singapore (i'm aussie) and looking to
>learn from a guy who is a little switched on, i checked locally to find
>someone to teach me in aus, but this is a real dieing trade. I'm happy
>to pay someone to help me out and hell, i'll send you a web cam so we
>can communicate (love the internet).

You sound like where I was about a year ago. It's definitely a steep
learning curve.

The number one thing you're going to need is the schematics. If you
don't have schematics then stop now. It's really hard to fix something
if you don't know how it is supposed to work and what's connected to
what. Yes, eventually as you get more familiar with electronics theory
and concepts you can do some basic troubleshooting on boards that you
don't have any schematics for, but that takes time.

It also helps to be really good at troubleshooting and critical
thinking. Most repairs aren't going to be something you can follow a
flow chart to fix, you're going to have to understand what's going on
and what's going wrong and be able to trace something back to find
what *is* working. My background of doing programming and network
administration (yes one of those freaks that can do both well), as
well as a bit of mechanical engineering probably helps. I've also
always been the one in the family that people ask to fix their broken
stuff, or at parties they hand me their presents that "require some
assembly". :-)

Your "internet classroom" idea is intriguing. You might need quite a
few webcams on your end though so the "instructor" can see what all
your equipment is doing as well as where you are poking at on the
board.

--
Please see my arcade and pinball items for sale:
http://www.videoracer.com/forsale/
Or check my repair logs:
http://blog.videoracer.com/blog/
Anonymous
April 26, 2005 7:46:14 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

In article <1114527876.998281.280980@f14g2000cwb.googlegroups.com>,
_NathanK_ <nkulinitsch@gmail.com> wrote:
>again, more keen to speak with someone to get the basics of what to
>look for.. not nessisarily how each component works individually... but
>how to break the system up into troubleshootable bits.

Ok, here's what I do:

Hook up board to test bench and fire it up and see what the problem
is. If it's something I've seen before (which doesn't happen too
often) then I do what I did last time and see if it worked.

If it's not something I've seen before, I pull out the schematics and
start digging through them following the logic and looking for parts
that probably are part of the circuit that *appears* to be
malfunctioning. Then I'll check voltages and/or fiddle with the logic
probe to see if a part looks like it's doing the right thing.

If it doesn't look right then I'll try to do a little more backtracing
to see if there's anything further upstream that might be bad
(hopefully to find something that's socketed and an easy swap).

If the part appears ok then it's back to the schematic to re-study the
logic and try again.

Google searches can help occasionally (which is why I've been trying
to post my repair logs) but for arcade PCBs it seems like most of the
time they don't turn up much of anything.

--
Please see my arcade and pinball items for sale:
http://www.videoracer.com/forsale/
Or check my repair logs:
http://blog.videoracer.com/blog/
Anonymous
April 26, 2005 9:27:25 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Don't you worry about the danger of ungrounding the scope when plugging it
into an isolation transformer?


Thanks,

Frank

"J & R" <arcadeadventures@aol.com> wrote in message
news:1114528722.688299.258840@g14g2000cwa.googlegroups.com...

> 9: Good Scope. Dual Trace with memory store is perfered.
> 10: ISOLATION TRANSFORMER For your test equipment to plug into
> Very important when you start probing around Monitor boards.
Anonymous
April 27, 2005 12:04:45 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

unless you have an in-circuit emulator it's generally not an easy thing to
debug logic running at full speed...

if you have an analyzer that lets you set complex triggers (and enough
probes/depth to make it feasable) then you can capture bus activity at
different points and see where things aren't correct.

Of course, shotgunning may very well make sense for older boards... the cost
of even a dozen 74xx parts is generally negligable compared to the time it
takes to narrow the problem down... especially if you're quick at
de-soldering/soldering (I'm not!)

steve

"_NathanK_" <nkulinitsch@gmail.com> wrote in message
news:1114527876.998281.280980@f14g2000cwb.googlegroups.com...
> Guys, i'm in the same boat as phil. I'm a network engineer by trade.
> i know how to read a schematic, i know how to what ram/rom/proc does
> and i also know what logic gates are and how they work.
>
> what i lack is being able to look at a galaxian board that gives junk
> on the screen, know where that problem is being caused (is it ram? or
> is it in the data path somewhere?) where to find the "rough" area to
> look. At the moment, i sit down with my logic analyzer, hook up the
> clips to all legs on 8080 and see whats giving me either a constant 0.
> If all legs are buzzing, then i used my probe to poke around the board.
> If most of the chips are buzzing, than i have 0 idea what to do next.
>
> What i need is someone to bounce questions off. I've tried it before in
> this NG and all i get is "replace ram/rom/cpu/74LS245's"... which is
> not very helpful... i belive this is called "shot gun" ;P...
>
> I dont mind doing the reading, if i get some decent books... i've tried
> the randy from stuff and its actually not very good. It jumps from
> being basic circuit stuff to "and thats how to fix a board" with no
> real actual troubleshooting demo's in the middle.
>
> again, more keen to speak with someone to get the basics of what to
> look for.. not nessisarily how each component works individually... but
> how to break the system up into troubleshootable bits.
>
> -nat
>
April 27, 2005 12:48:44 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

start from the basics and get a logic probe. Learn how to read the
schematics and get to know the pinout and function of the 74xx series of
chips! A quick look with a logic probe will tell you a lot if you know what
you are looking at.


"Phil" <mtksrtfix@ulmail.net> wrote in message
news:e3obe.74000$3X7.4992087@phobos.telenet-ops.be...
> About the same story here... Would really like to get into PCB repairs,
but
> not much information available that goes beyond "check eproms & reseat
> socketed IC's"...
>
> Haven't got that 32 channel analyzer & fluke scope either :-(
>
> I was also looking for the repair logs but the ftp site for this group
seems
> to be unavailable.
>
> Hopefully someone will get back on this...
>
>
> "_NathanK_" <nkulinitsch@gmail.com> wrote in message
> news:1114507675.438311.85630@f14g2000cwb.googlegroups.com...
> > Hi Guys,
> >
> > i have been arcade collecting for about a year now and i have decided
> > to get into repair... i recently splashed out and got a 32 channel
> > analyzer, a fluke scope and a kick arse soldering station with the hope
> > of reparing some of my "unknown condition" ebay bargins (bargins for a
> > reason).
> >
> > i had a shot at it a few times, trying to repair some dead galaxians
> > and a dead pacmans... but couldnt work it out on my own. read the
> > repair guides, 3 or 4 times over for both games and not a whole lot of
> > help.
> >
> > so guys, i'm looking for a vetran who might be interested in teaching a
> > repair newbie. I'm located in singapore (i'm aussie) and looking to
> > learn from a guy who is a little switched on, i checked locally to find
> > someone to teach me in aus, but this is a real dieing trade. I'm happy
> > to pay someone to help me out and hell, i'll send you a web cam so we
> > can communicate (love the internet).
> >
> > is there anyone out there interested in maybe mentoring me a little, to
> > get me started in the basics of repair? promise i wont pester you with
> > massive long complicated emails... and hell, i'll even paypal you some
> > cash for your time.
> >
> > let me know if anyone is intersted.
> >
> > -nat
> >
>
>
Anonymous
April 27, 2005 12:48:45 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

>get a logic probe

He doesn't need one... he went and bought himself a 32 channel logic
analyzer...

He he... just wait until he bumps something and all those little frigging
clips come popping off! you NEVER get them back where they were the first
time

"VaxX" <geoff_gunn@hotmail.com> wrote in message
news:426e1c8e$0$257$61c65585@uq-127creek-reader-03.brisbane.pipenetworks.com.au...
> start from the basics and get a logic probe. Learn how to read the
> schematics and get to know the pinout and function of the 74xx series of
> chips! A quick look with a logic probe will tell you a lot if you know
> what
> you are looking at.
>
>
> "Phil" <mtksrtfix@ulmail.net> wrote in message
> news:e3obe.74000$3X7.4992087@phobos.telenet-ops.be...
>> About the same story here... Would really like to get into PCB repairs,
> but
>> not much information available that goes beyond "check eproms & reseat
>> socketed IC's"...
>>
>> Haven't got that 32 channel analyzer & fluke scope either :-(
>>
>> I was also looking for the repair logs but the ftp site for this group
> seems
>> to be unavailable.
>>
>> Hopefully someone will get back on this...
>>
>>
>> "_NathanK_" <nkulinitsch@gmail.com> wrote in message
>> news:1114507675.438311.85630@f14g2000cwb.googlegroups.com...
>> > Hi Guys,
>> >
>> > i have been arcade collecting for about a year now and i have decided
>> > to get into repair... i recently splashed out and got a 32 channel
>> > analyzer, a fluke scope and a kick arse soldering station with the hope
>> > of reparing some of my "unknown condition" ebay bargins (bargins for a
>> > reason).
>> >
>> > i had a shot at it a few times, trying to repair some dead galaxians
>> > and a dead pacmans... but couldnt work it out on my own. read the
>> > repair guides, 3 or 4 times over for both games and not a whole lot of
>> > help.
>> >
>> > so guys, i'm looking for a vetran who might be interested in teaching a
>> > repair newbie. I'm located in singapore (i'm aussie) and looking to
>> > learn from a guy who is a little switched on, i checked locally to find
>> > someone to teach me in aus, but this is a real dieing trade. I'm happy
>> > to pay someone to help me out and hell, i'll send you a web cam so we
>> > can communicate (love the internet).
>> >
>> > is there anyone out there interested in maybe mentoring me a little, to
>> > get me started in the basics of repair? promise i wont pester you with
>> > massive long complicated emails... and hell, i'll even paypal you some
>> > cash for your time.
>> >
>> > let me know if anyone is intersted.
>> >
>> > -nat
>> >
>>
>>
>
>
Anonymous
April 27, 2005 1:36:40 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Never mind the analyzer, and you can even pretty much skip the scope unless
you are doing monitors.
Get a DMM, a logic probe, a logic pulser, and an HP10529A setup to check ICs
live in circuit and go from there. Lay in a supply of different crystals at
a buck or so each - without a scope, I would just swap the crystal before
doing any troubleshooting.

--
Art
"Phil" <mtksrtfix@ulmail.net> wrote in message
news:e3obe.74000$3X7.4992087@phobos.telenet-ops.be...
> About the same story here... Would really like to get into PCB repairs,
> but not much information available that goes beyond "check eproms & reseat
> socketed IC's"...
>
> Haven't got that 32 channel analyzer & fluke scope either :-(
>
> I was also looking for the repair logs but the ftp site for this group
> seems to be unavailable.
>
> Hopefully someone will get back on this...
>
>
> "_NathanK_" <nkulinitsch@gmail.com> wrote in message
> news:1114507675.438311.85630@f14g2000cwb.googlegroups.com...
>> Hi Guys,
>>
>> i have been arcade collecting for about a year now and i have decided
>> to get into repair... i recently splashed out and got a 32 channel
>> analyzer, a fluke scope and a kick arse soldering station with the hope
>> of reparing some of my "unknown condition" ebay bargins (bargins for a
>> reason).
>>
>> i had a shot at it a few times, trying to repair some dead galaxians
>> and a dead pacmans... but couldnt work it out on my own. read the
>> repair guides, 3 or 4 times over for both games and not a whole lot of
>> help.
>>
>> so guys, i'm looking for a vetran who might be interested in teaching a
>> repair newbie. I'm located in singapore (i'm aussie) and looking to
>> learn from a guy who is a little switched on, i checked locally to find
>> someone to teach me in aus, but this is a real dieing trade. I'm happy
>> to pay someone to help me out and hell, i'll send you a web cam so we
>> can communicate (love the internet).
>>
>> is there anyone out there interested in maybe mentoring me a little, to
>> get me started in the basics of repair? promise i wont pester you with
>> massive long complicated emails... and hell, i'll even paypal you some
>> cash for your time.
>>
>> let me know if anyone is intersted.
>>
>> -nat
>>
>
>
Anonymous
April 27, 2005 1:40:32 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

I would be willing to host (no charge of course) any repair logs, and try to
put together a central repository of them

--
Art
"Craig Yarbrough" <hyarbr01@harris.com> wrote in message
news:1114536731.556314.231720@f14g2000cwb.googlegroups.com...
> Anytime! ;-)
>
> Sure would be cool if there was a Spies site dedicated to repair logs.
> Most repair logs I've seen have been on individual's webpages, and if
> detailed, then usually specific to one game. Try:
>
> http://coinop.org/repair/index.aspx
>
> ...or maybe:
>
> http://www.ionpool.net/
>
> - Craig
>
Anonymous
April 27, 2005 3:16:30 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Art,
Do you really see Xtals go that often? I've swapped a few out in my
troubleshooting (read: shotgunning), but I've yet to see one actually be the
problem...

Rob


"Art Mallet - Artfromny - formerly A218@aol.com" <artgames@nycap.rr.com>
wrote in message news:Ivybe.8685$Bc7.2358@twister.nyroc.rr.com...
> Never mind the analyzer, and you can even pretty much skip the scope
> unless you are doing monitors.
> Get a DMM, a logic probe, a logic pulser, and an HP10529A setup to check
> ICs live in circuit and go from there. Lay in a supply of different
> crystals at a buck or so each - without a scope, I would just swap the
> crystal before doing any troubleshooting.
>
> --
> Art
> "Phil" <mtksrtfix@ulmail.net> wrote in message
> news:e3obe.74000$3X7.4992087@phobos.telenet-ops.be...
>> About the same story here... Would really like to get into PCB repairs,
>> but not much information available that goes beyond "check eproms &
>> reseat socketed IC's"...
>>
>> Haven't got that 32 channel analyzer & fluke scope either :-(
>>
>> I was also looking for the repair logs but the ftp site for this group
>> seems to be unavailable.
>>
>> Hopefully someone will get back on this...
>>
>>
>> "_NathanK_" <nkulinitsch@gmail.com> wrote in message
>> news:1114507675.438311.85630@f14g2000cwb.googlegroups.com...
>>> Hi Guys,
>>>
>>> i have been arcade collecting for about a year now and i have decided
>>> to get into repair... i recently splashed out and got a 32 channel
>>> analyzer, a fluke scope and a kick arse soldering station with the hope
>>> of reparing some of my "unknown condition" ebay bargins (bargins for a
>>> reason).
>>>
>>> i had a shot at it a few times, trying to repair some dead galaxians
>>> and a dead pacmans... but couldnt work it out on my own. read the
>>> repair guides, 3 or 4 times over for both games and not a whole lot of
>>> help.
>>>
>>> so guys, i'm looking for a vetran who might be interested in teaching a
>>> repair newbie. I'm located in singapore (i'm aussie) and looking to
>>> learn from a guy who is a little switched on, i checked locally to find
>>> someone to teach me in aus, but this is a real dieing trade. I'm happy
>>> to pay someone to help me out and hell, i'll send you a web cam so we
>>> can communicate (love the internet).
>>>
>>> is there anyone out there interested in maybe mentoring me a little, to
>>> get me started in the basics of repair? promise i wont pester you with
>>> massive long complicated emails... and hell, i'll even paypal you some
>>> cash for your time.
>>>
>>> let me know if anyone is intersted.
>>>
>>> -nat
>>>
>>
>>
>
>
Anonymous
April 27, 2005 3:33:42 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Rob Carroll <spy.hunter@verizon.net> wrote:
: Art,
: Do you really see Xtals go that often? I've swapped a few out in my
: troubleshooting (read: shotgunning), but I've yet to see one actually be the
: problem...


I've seen a LOT of atari crystals broken off or otherwise damaged and
non-functional, since they mout perpendicular to the board.

I just bought 100 each of 10Mhz, 12Mhz, 18.432Mhz crystals in addition to
the handful of other values I keep around just in case.

--
Mark Spaeth mspaeth@mtl.mit.edu
50 Vassar St., #38.265 mspaeth@mit.edu
Cambridge, MA 02139
(617) 452-2354 http://rgvac.978.org/~mspaeth
Anonymous
April 27, 2005 3:51:18 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

I changed a few in BZ boards that were totally dead and found one in an
Asteroids - sometimes tho I think its just from rough handling of the boards
that damages them

--
Art
"Rob Carroll" <spy.hunter@verizon.net> wrote in message
news:iZzbe.11478$Nc.6902@trnddc09...
> Art,
> Do you really see Xtals go that often? I've swapped a few out in my
> troubleshooting (read: shotgunning), but I've yet to see one actually be
> the problem...
>
> Rob
>
>
> "Art Mallet - Artfromny - formerly A218@aol.com" <artgames@nycap.rr.com>
> wrote in message news:Ivybe.8685$Bc7.2358@twister.nyroc.rr.com...
>> Never mind the analyzer, and you can even pretty much skip the scope
>> unless you are doing monitors.
>> Get a DMM, a logic probe, a logic pulser, and an HP10529A setup to check
>> ICs live in circuit and go from there. Lay in a supply of different
>> crystals at a buck or so each - without a scope, I would just swap the
>> crystal before doing any troubleshooting.
>>
>> --
>> Art
>> "Phil" <mtksrtfix@ulmail.net> wrote in message
>> news:e3obe.74000$3X7.4992087@phobos.telenet-ops.be...
>>> About the same story here... Would really like to get into PCB repairs,
>>> but not much information available that goes beyond "check eproms &
>>> reseat socketed IC's"...
>>>
>>> Haven't got that 32 channel analyzer & fluke scope either :-(
>>>
>>> I was also looking for the repair logs but the ftp site for this group
>>> seems to be unavailable.
>>>
>>> Hopefully someone will get back on this...
>>>
>>>
>>> "_NathanK_" <nkulinitsch@gmail.com> wrote in message
>>> news:1114507675.438311.85630@f14g2000cwb.googlegroups.com...
>>>> Hi Guys,
>>>>
>>>> i have been arcade collecting for about a year now and i have decided
>>>> to get into repair... i recently splashed out and got a 32 channel
>>>> analyzer, a fluke scope and a kick arse soldering station with the hope
>>>> of reparing some of my "unknown condition" ebay bargins (bargins for a
>>>> reason).
>>>>
>>>> i had a shot at it a few times, trying to repair some dead galaxians
>>>> and a dead pacmans... but couldnt work it out on my own. read the
>>>> repair guides, 3 or 4 times over for both games and not a whole lot of
>>>> help.
>>>>
>>>> so guys, i'm looking for a vetran who might be interested in teaching a
>>>> repair newbie. I'm located in singapore (i'm aussie) and looking to
>>>> learn from a guy who is a little switched on, i checked locally to find
>>>> someone to teach me in aus, but this is a real dieing trade. I'm happy
>>>> to pay someone to help me out and hell, i'll send you a web cam so we
>>>> can communicate (love the internet).
>>>>
>>>> is there anyone out there interested in maybe mentoring me a little, to
>>>> get me started in the basics of repair? promise i wont pester you with
>>>> massive long complicated emails... and hell, i'll even paypal you some
>>>> cash for your time.
>>>>
>>>> let me know if anyone is intersted.
>>>>
>>>> -nat
>>>>
>>>
>>>
>>
>>
>
>
Anonymous
April 27, 2005 4:55:21 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Thanks guys for the massive reply... lots of helpful info in here, but
alas not a whole lot new :) 

i'll start working on one of my galaxians over the next few days and
post out with some pics and see if i can work one of these puppies out.

-nat
Anonymous
April 27, 2005 11:18:41 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

>(1) I will see if I can get ahold of a cheap logic probe on eBay.
Although I
>have no idea how to use it yet one day it may prove useful. I do
understand
>that it kind of visualizes the data signals (<0.8v = 0; > 2.4v = 1) if
a
>line is always 0 or 1 it might indicate a possible failure (although
not
>necessarely it is to be considered one).

Logic probes are a great tool and can easily locate a "stuck at" fault.
(I.E. a pin is stuck at a 1 or a 0) You can even find these at radio
shack...

>(2) I was surprised about the remarks with respect to reading the
>schematics. I thought for most of these pcb's schematics are hard to
find
>and you are kind of supposed to work it out on your own.

Depends... most of the schematics for the classics are out there:
www.arcadehelp.com
www.arcadedocs.com
etc

But alot of the newer JAMA stuff in not, which is why most guys will
not touch Jamma. Not to mention that fact that alot of the JAMMA stuff
is more advanced (smaller IC footprints, more complex architecture,
etc) which maked debugging them all the more difficult.

>(3) Are there any sites/references/books you can suggest regarding the
stuff
>you think one should have knowledge about before looking at the actual
pcb
>boards. I am a software programmer myself (btw good luck with that
OpenGL
>programming) and I do know how some of these things (are supposed to)
work
>from a users point of view...
A book in digital electronics goes along way. Althought I can't really
recommend one personaly, because th only one I ownis my college
textbook:
Contemporary Logic Design by Randy Katz. And what you ya know? You can
read it online:
http://www2.ele.ufes.br/~ailson/digital2/cld/CLD.html

>I've been reading quite
>a bit about resistors, transistors, capacitors and more stuff like
that and
>have a basic idea what they do on their own. When you put them on a
full
>blown pcb board it doesnt make that much sense anymore though

I aggree.. looking ata full blown schematic is overwhelming. Once you
understand digital design, however, you look at a schematic and it
falls apart right before your eyes: "Oh this is the addressing
circuitry, and here's the DRAM controller circuitry, and here's the
watch dog timer, etc, etc)


>Anyway these boards are
>full of IC's (especially 74XX logic), some ROM and RAM chips and a few
>microprocessors (Z80/MC68000) and not too many of those single
components
>the electronics courses I found on the net seem to focus on...
Most of the electronics courses teach the fundimantals of electronics
and electronics theory. All of which is the core behind analog
electronics. Arcade PCBs, as you have discovered, are 80-90% digital
electronics. And Prof Katz's book above will get you started with
that. Alot of people don't realize that analog and digital electrical
engineering are two very different fields.

>(4) At this moment I am looking at a pcb board which seems to have
dynamic
>"noise" in its background. I don't think it is a rom problem (as the
data is
>not wrong, there is just noise on a per 8x8 tile basis) but don't know
how
>to solve it. Actually I think something is broking in the video
circuitry
>(ram chip ? how do I even find the video circuitry on the board ?)
but have
>no idea how to isolate/deduct the problem. I don't have any spare rams
>available at the moment (is piggy backing just putting the same chip
on top
>of the on board chip ?) so it is hard to test. If the problem is in
one of
>the logic chips I have no idea where to start looking (I suppose this
is the
>point where the logic probe comes into play).
Before you even whip out that probe. let's look at the problem. You
know it's video related. So start at the RBG signals and work your way
back. Now I'm not saying start pobing those signals and work your way
back... look at the schematic and work your way back. You will
probbaly find a color PROM along the way.. and then perhaps a data MUX
or two... you'l probably hit the charater ROMS (which have the sprites
inside of them) and then to the video ram (which tells the charater
ROMS which image to draw on the screen).

So lets look at some scinereos:
1)Bad RAM
Hmmm. not likely. If the ram was wrong then the wrong values would be
sent to the charater ROMs and the the charaters themselves would be
messed up.
Fluke 9010A comes in real handy here as it can verify that the video
RAM is good and can eliminate that variable from the equation.

2) Bad character ROM
Are the charaters totaly messed up? Or just colored boxes? If not
then your rom is probably fine.

3) Poorly seated ROM
Could be... the data from the rom goes to the color PROM circuity
which sends an RGB value to the screen. Is a pin in "floating" (I.E.
not a 0 or 1 but somewhere in the middle) then this signal is randomly
teling the PROM to draw a color or not.

4) Any other floating pin or poorly seated IC from the charater ROM to
the RGB signals
Could easily cause this behavior as described above.

See what I mean about poper debugging? Why waste your time reseating
program ROMS and the like when you know (or will know one you get a
litle more education under your belt :-) ) where to be looking.
And keep in mind too that a logic probe is interpreting the signal just
as the rest of the harware is. If the pin is floating the probe may
tell you it's toggleing (changing from 1 to 0 over and over) even
though it's not. Although some of the newer probes can detect floating
pins.

Fweeeew... that was a long reply. But hopefully you get the idea. Take
the time to understand digital electronics a little bit more and you'll
be up and running.
Anonymous
May 2, 2005 9:58:11 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Just as an ironic (apropos?) sidenote to all this... had a totally dead
Asteroids Deluxe board.... no heartbeat at all...

You guessed it, Xtal broken off. 12.096 stolen off a broke BZ... yay!

Rob
Anonymous
May 10, 2005 9:10:35 PM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Off who's broke BZ??
Anonymous
May 11, 2005 12:31:07 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Nat,

I definitely agree with everybody else that you should first learn
about how embedded systems work in order to gain a better understanding of
how to repair boards; however I'd wager that there have been many
successful arcade technicians that didn't have a really good understanding
about how everything was working together.

That being said, here are some of the steps that I follow when
troubleshooting a board.

1) With your knowledge of embedded systems, try to make an
educated guess about what part of the board is failing. For example, if
only the foreground video (i.e. the moving things like the players,
enemies, etc) is messed up then the section that controls the foreground
video has a problem. If you are getting a black screen or just garbage
with no video or sound, then something "catastrophic" has gone wrong with
the board (actually, in the case of board repair, "catastrophic" is good
in that it's usually easier to find these sorts of problems.) In these
cases, it is likely that the processor is not working because:

a) It's just not working (i.e. the processor chip itself is bad)
b) It's not getting power (check that the power ON THE BOARD is
within specifications)
c) It's being reset (check the watchdog reset circuit and see (b)
above)
d) It can't communicate with its memory/IO (either because the
memory itself, or the memory bus controllers are bad)
e) Something else, but usually if (a) - (d) are OK, the game will
usually be able to provide you with some useful information through its
self-test (if it has one.)

There is a lot more to learn than this, but understanding how to
troubleshoot and fix (a) - (d) above will help you fix in excess of 90%
(in my experience) of board problems. The tools/supplies you need to do
this are:

a) Extra processor chip(s) to swap out OR, a Fluke 9010
troubleshooter with the appropriate pod. The 9010 can run the game with
the processor built-in to the pod.
b) Voltmeter. Even the cheapest one you can buy will be able to
help you with this problem, but if you want to make a habit of repairing
boards and can afford it, but a good Fluke DVM. I'm sure that there've
been lots of posts recommending DVMs.
c) Logic probe. Sometimes a DVM and/or scope can be useful here,
but usually not necessary.
d) Here is where the Fluke 9010 can be invaluable. It can
perform bus tests and memory read and write tests. You'll need to know
the game's memory map (which is sometimes given in the manual/schematics,
but you'll need to be able to figure it out at other times.) A logic
probe can be used to look for stuck address/data lines, if you don't have
a Fluke 9010. Sometimes the game's self-test can be helpful here, but
many times it won't, or the game is not able to function to a level where
it can even run the self-test.

In summary: To fix 90% of board problems you are likely to face,
you need:

1) A basic knowledge of these kinds of systems
2) A Voltmeter
3) A logic probe
4) A Fluke 9010, if you are seriously thinking of doing lots of
board repairs. If you are just tinkering with a few boards, you can
usually figure out basic problems like these with a logic probe, but it
may take longer.

In my experience, there is no "easy" way to fix most of the other
problems you are likely to face (i.e. the other 10%.) It takes an
interest in the board, time to understand what is going on, and lots of
time and patience to try different experiments to try to figure out what
is going on. Even then, you may not be able to fix everything. I still
have 2 boards that I haven't been able to fix, period. I've tried nearly
everything I can think of, but haven't figured the out yet.

Resist to ugre to "shotgun" and replace everything on the board.
When desoldering chips, etc, you run the risk of breaking traces/vias in
the board. Those kinds of problems are the hardest/most time-consuming to
troubleshoot, and in the end, you usually just wind up wasting more time
than if you spent some time trying to figure out what was going on with
your bad board.

That's probably more information than is useful at once, but I had
some spare time to do a core dump of a summary of what has worked for me.

Most of all, HAVE FUN! (And if you don't think it's fun, at least
to some extent, pay someone else to do it, or find another working board.)

Joe

_NathanK_ <nkulinitsch@gmail.com> wrote:
: Hi Guys,

: i have been arcade collecting for about a year now and i have decided
: to get into repair... i recently splashed out and got a 32 channel
: analyzer, a fluke scope and a kick arse soldering station with the hope
: of reparing some of my "unknown condition" ebay bargins (bargins for a
: reason).

: i had a shot at it a few times, trying to repair some dead galaxians
: and a dead pacmans... but couldnt work it out on my own. read the
: repair guides, 3 or 4 times over for both games and not a whole lot of
: help.

: so guys, i'm looking for a vetran who might be interested in teaching a
: repair newbie. I'm located in singapore (i'm aussie) and looking to
: learn from a guy who is a little switched on, i checked locally to find
: someone to teach me in aus, but this is a real dieing trade. I'm happy
: to pay someone to help me out and hell, i'll send you a web cam so we
: can communicate (love the internet).

: is there anyone out there interested in maybe mentoring me a little, to
: get me started in the basics of repair? promise i wont pester you with
: massive long complicated emails... and hell, i'll even paypal you some
: cash for your time.

: let me know if anyone is intersted.

: -nat
Anonymous
May 11, 2005 3:45:44 AM

Archived from groups: rec.games.video.arcade.collecting (More info?)

Not yours. :^)

"Gary Vitagliano" <v-dog@webtv.net> wrote in message
news:29832-4281234B-601@storefull-3213.bay.webtv.net...
> Off who's broke BZ??
>
!