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Space invaders comonent help

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Anonymous
August 18, 2005 8:25:28 PM

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

I've already convinced myself that at least one of these Space Invaders
Deluxe boards is being sent out, but I'm still trying to repair the other.

Found a cracked component just to the left of IC B3. It's green,
cylindrical, and has the markings "104z 50v vaz on it". I'm assuming a
capacitor, but I'd like to be sure before replacing it. If it is a cap, is
an electrolytic ok to pop in there?

Thanks.

More about : space invaders comonent

Anonymous
August 19, 2005 1:34:28 AM

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

Tony Tumminaro <TonyTumminaro@comcast.net> wrote:
: I've already convinced myself that at least one of these Space Invaders
: Deluxe boards is being sent out, but I'm still trying to repair the other.
:
: Found a cracked component just to the left of IC B3. It's green,
: cylindrical, and has the markings "104z 50v vaz on it". I'm assuming a
: capacitor, but I'd like to be sure before replacing it. If it is a cap, is
: an electrolytic ok to pop in there?

..1uF ceramic.

--
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
August 19, 2005 1:34:29 AM

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

Thanks to all that replied. After replacing the cracked cap, no real changes
were noted on this board. I think I have traced a problem down to somewhere
near the 74166 at C4. It looks to be pulsing with a logic probe, but it's
getting pretty hot, and all of the outputs are pulsed-lows. I tapped a
couple of the outputs high with a jumper and actually got something flashing
on the whole screen, instead of just the corner. It was still garbage, but
progress is progress.





"Mark C. Spaeth" <mspaeth@plancherel.mit.edu> wrote in message
news:4304fee4$0$568$b45e6eb0@senator-bedfellow.mit.edu...
> Tony Tumminaro <TonyTumminaro@comcast.net> wrote:
> : I've already convinced myself that at least one of these Space Invaders
> : Deluxe boards is being sent out, but I'm still trying to repair the
> other.
> :
> : Found a cracked component just to the left of IC B3. It's green,
> : cylindrical, and has the markings "104z 50v vaz on it". I'm assuming a
> : capacitor, but I'd like to be sure before replacing it. If it is a cap,
> is
> : an electrolytic ok to pop in there?
>
> .1uF ceramic.
>
> --
> 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
>
Related resources
Anonymous
August 19, 2005 3:11:14 AM

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

Tony Tumminaro <TonyTumminaro@comcast.net> wrote:
: Thanks to all that replied. After replacing the cracked cap, no real changes
: were noted on this board. I think I have traced a problem down to somewhere
: near the 74166 at C4. It looks to be pulsing with a logic probe, but it's
: getting pretty hot, and all of the outputs are pulsed-lows. I tapped a
: couple of the outputs high with a jumper and actually got something flashing
: on the whole screen, instead of just the corner. It was still garbage, but
: progress is progress.

It's getting hot because it's shifting bits at the full clock speed.

--
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
August 19, 2005 4:40:03 PM

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

> It's getting hot because it's shifting bits at the full clock speed.

And it would also play blind (I'm assuming it isn't) if that were the only problem.

Alex
----
ayeckley@elektronforge.com
www.elektronforge.com
Anonymous
August 19, 2005 4:40:04 PM

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

Yeah, there seems to be a few things going on. That last post lead me to the
7404 @A7, and pins 3-4 and 5-6 showing some weak/improper signals. After
replacing (poorly at that) the 7404, the signals are correct off of those
pins now, but on occasion it takes a short on that same IC between pins 6 +
gnd to get the clock circuit to start ticking. Looking at the tank circuit
components now.

On the other board, the 12v rail seems shorted somewhere, and I get roughly
less than a volt on that line and the 5v line when turned on. If the 12v
rail isn't connected the 5v rail powers up fine, as does the -5v. I think I
have the problem traced to the 4 ram IC's at G or H, 14 or 15.

I keep meaning to put one of these in a box to you, but I'm having a lot of
fun trying to peg this down. I just hope I don't do more damage than good


"Alex Yeckley" <ayeckley@elektronforge.com> wrote in message
news:D qkNe.2410$AT7.2337@newssvr22.news.prodigy.net...
>> It's getting hot because it's shifting bits at the full clock speed.
>
> And it would also play blind (I'm assuming it isn't) if that were the only
> problem.
>
> Alex
> ----
> ayeckley@elektronforge.com
> www.elektronforge.com
>
>
Anonymous
August 20, 2005 3:25:30 AM

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

> I keep meaning to put one of these in a box to you, but I'm having a lot of fun trying to peg this down. I just hope I don't do
> more damage than good

You probably should fix the power supply short first then. The RAMs can be
damaged if the three required voltages (-5, +5, +12) aren't all present and accounted
for.

Alex
----
ayeckley@elektronforge.com
www.elektronforge.com
Anonymous
August 20, 2005 3:25:31 AM

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

"Alex Yeckley" <ayeckley@elektronforge.com> wrote in message
news:KTtNe.3615$Z%6.2082@newssvr17.news.prodigy.com...
>> I keep meaning to put one of these in a box to you, but I'm having a lot
>> of fun trying to peg this down. I just hope I don't do more damage than
>> good
>
> You probably should fix the power supply short first then. The RAMs can
> be
> damaged if the three required voltages (-5, +5, +12) aren't all present
> and accounted
> for.
>



Both the power supply boards are fine now, fixed them a long time ago. I
have two separate SI deluxe Board sets. The first board is the one I have
been writing about in the earlier post, the one with the IC's geting a
little warm and the garbage in the screen. That boards voltages are all
great. The second board is the one with the voltage issue. I haven't done
much with that other than trace the short down to somewhere very early on in
the 12v power rail. Possible the first 4 ram modules, but I haven't spent
enough time with that board to be sure.


I wish I wasn't so inquisitiveon these, I could have probably had one of
these boards sent to you and repaired by now..... :) 
August 22, 2005 1:02:13 AM

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

> On the other board, the 12v rail seems shorted somewhere, and I get
roughly
> less than a volt on that line and the 5v line when turned on. If the 12v
> rail isn't connected the 5v rail powers up fine, as does the -5v. I think
I
> have the problem traced to the 4 ram IC's at G or H, 14 or 15.
>
Tantalum caps will do this when they go bad.
Anonymous
August 22, 2005 1:02:14 AM

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

Ruled them out already. Replaced them anyway, for some reason I have a
"tantalum=bad" mentality stuck in my head.

"VaxX" <geoff_gunn@hotmail.com> wrote in message
news:43085f36$0$22652$61c65585@uq-127creek-reader-03.brisbane.pipenetworks.com.au...
>
>> On the other board, the 12v rail seems shorted somewhere, and I get
> roughly
>> less than a volt on that line and the 5v line when turned on. If the 12v
>> rail isn't connected the 5v rail powers up fine, as does the -5v. I think
> I
>> have the problem traced to the 4 ram IC's at G or H, 14 or 15.
>>
> Tantalum caps will do this when they go bad.
>
>
!