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TECH: Strange Galaga Images

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Anonymous
a b C Monitor
September 15, 2005 1:03:39 PM

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

Hi all,

I am an avid pinball collector, but recently picked up a Galaga
Upright. I have very little monitor troubleshooting experience, but I
want to learn.

I am having trouble tracking down a strange monitor issue:

Please view screenshots of the images here:
http://www.xsworks.com/Galaga

My Galaga hangs at the "RAM OK" stage of the self-test, but thats ok
for now, I'm more concerned in getting the monitor working first.
Anyway, I could see the "RAM OK" error, but the image was smashed top
to bottom with several inches of black border on top and bottom.

Installed cap kit in my K4600 monitor, resoldered all solder points on
the daughter boards, resoldered connector points on main PCB. Now the
image is worse.

Would someone with monitor troubleshooting experience take a look at
the images I posted to my website above and see if this looks like
sometime familiar to them? It appears to be several narrow strips, then
changes to a solid blue screen with a few white dots... Is this a
H-Hold or V-Hold issue?

Thanks!
Tony
Anonymous
a b C Monitor
September 15, 2005 10:37:27 PM

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

Thanks Matt for the response!

Since this monitor (K4600) is mounted vertically, is it really a
horizontal adjustment, or is it vertical? I think the 4600 in Galaga
cabinets is a horizontal unit, mounted vertically? Just wanted to
double check before I go digging in the monitor...

Thansk!
Tony





Matt J. McCullar wrote:
> That appears to be a horizontal hold issue. Try tweaking the H-HOLD or
> H-FREQ adjustment (whichever your monitor has) and see if that helps.
Anonymous
a b C Monitor
September 16, 2005 4:48:51 AM

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

That appears to be a horizontal hold issue. Try tweaking the H-HOLD or
H-FREQ adjustment (whichever your monitor has) and see if that helps.
Related resources
Anonymous
a b C Monitor
September 16, 2005 10:53:44 PM

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

Well, it's all BLUE so no amount of sync adjustment is going to fix that. It
is possible that the blue gun has a short putting it full on, and adjusting
the hold will help you read text if any is there. I'd check Vcc first. 5.1V
would be where I'd start if it's hanging on the boot, and of course you've
cleaned the legs on all the custom chips?

<trossi@hotmail.com> wrote in message
news:1126800219.525562.92260@o13g2000cwo.googlegroups.com...
> Hi all,
>
> I am an avid pinball collector, but recently picked up a Galaga
> Upright. I have very little monitor troubleshooting experience, but I
> want to learn.
>
> I am having trouble tracking down a strange monitor issue:
>
> Please view screenshots of the images here:
> http://www.xsworks.com/Galaga
>
> My Galaga hangs at the "RAM OK" stage of the self-test, but thats ok
> for now, I'm more concerned in getting the monitor working first.
> Anyway, I could see the "RAM OK" error, but the image was smashed top
> to bottom with several inches of black border on top and bottom.
>
> Installed cap kit in my K4600 monitor, resoldered all solder points on
> the daughter boards, resoldered connector points on main PCB. Now the
> image is worse.
>
> Would someone with monitor troubleshooting experience take a look at
> the images I posted to my website above and see if this looks like
> sometime familiar to them? It appears to be several narrow strips, then
> changes to a solid blue screen with a few white dots... Is this a
> H-Hold or V-Hold issue?
>
> Thanks!
> Tony
>
Anonymous
a b C Monitor
September 17, 2005 5:12:30 AM

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

<trossi@hotmail.com> wrote in message
news:1126834647.305043.73250@o13g2000cwo.googlegroups.com...
> Thanks Matt for the response!
>
> Since this monitor (K4600) is mounted vertically, is it really a
> horizontal adjustment, or is it vertical? I think the 4600 in Galaga
> cabinets is a horizontal unit, mounted vertically? Just wanted to
> double check before I go digging in the monitor...

I still think it's a horizontal sync issue. If you look at a generic video
monitor (even a television set) and purposely throw the horizontal sync
control out of whack, the picture will "tear" from left to right. If
instead you lose vertical sync, you'll see a constantly rolling picture up
or down, and if the vertical sync is REALLY way off, you may see multiple
copies of the video image stacked on top of each other.

You may want to double-check to see if the right signals are getting to the
right monitor inputs. The background raster looks a little too blue, and
there's a chance that the sync signal input pin on the monitor is actually
getting the blue video signal from the computer, and the blue video input is
getting the sync signal (or some such).
September 19, 2005 10:32:10 AM

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

Thanks everyone for the responses, I appreciate it!

Yes, I've cleaned all of the chip legs and verified continuity from all
of the chip legs to the solder points on the back of the board. I set
my switcher to put 5.1v at the Cap on the pcb. I figure I have a bad
z80 or bad rom somewhere...

As far as the monitor goes, I will try adjusting the horz sync this
evening and see whats up. The blue also has me concerned. If I get
the horz issue fixed, where should I start with the blue issue?

Thanks!
Tony
September 20, 2005 11:59:36 AM

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

Good News!!!

Adjusted L351 and now have a good image (well, better..)! Plus,
replaced the Z80 socket at 4E and now Galaga runs just fine...

See images here for a new monitor issue:
http://www.xsworks.com/galaga

Image is too blue and blue ghosting is appearing below graphics. Image
is pretty bright and shifted up a little too high. Any suggestions
would be great! Thanks!

Tony
Anonymous
a b C Monitor
September 20, 2005 1:05:44 PM

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

I might have missed it reading through the post, but have you adjusted
the blue drive pot on the neckboard? IIRC there are two additional
pots for setting the cut-offs.

If adjustment doesn't cure it, check for cold solder as some of the
drive circuits are designed where zero = full on. Beyond that it could
be a shorted transistor related to the blue drive circuit which you can
run down quickly using the diode test setting on your meter and
comparing it to the other two color circuit transistors on the
neckboard with the power off.

Watch out for that HV! (general warning to pin collectors dabbling in
vids, which I'm guilty of too :-)

Mike Doyle
September 22, 2005 4:28:15 PM

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

Galaga is Running!!!

Thanks to everyone who provided help in adjusting the monitor in my
Galaga. I adjusted the Blue level and then had to go back and turn the
nrightness way down. The new cap kit really made a difference.
Adjusted v/h pos and now its near perfect...

Thanks again everyone!
Tony
June 20, 2009 9:20:46 PM

I just recently bought a Galaga Cabinet is great shape (all original serial #13781). It didn't get past the "RAM OK" when I first powered it on, but I cleaned all the chips and it was working perfectly!

a few days ago I adjusted the convergence and purity rings on the tube as the picture was really bad in the corners and it was looking great see pic:

http://picasaweb.google.com/lh/photo...eat=directlink

I just powered in on today and it make a burning electronice smell and now it looks like this: :-(

http://picasaweb.google.com/lh/photo...eat=directlink

Does anyone know what this might be? A bad cap? I normally have no problem working with electronics, but monitors scare me -- I don't want to get zapped. It took quite a bit of bravery to adjust the rings. I really want to get the original monitor working -- seems like everyone is selling LCD replacements which bothers me.
!