Help me save this g07!

kstillin said:
Well, the H oscillator must be running or you wouldn't get any scanlines-

Do you have a scope?
Are you sure the sync signals are getting to the IC501?

Scope out pin 16 there.

Does the HFreq pot do ANYTHING?

Your comment about the starfield is pretty confusing. Do you see a starfield in that picture you posted? I can't see a starfield.

Does anything happen if you hook the sync pins up to the other inputs? (positive vs negative).
Click to expand...

No scope :(

If the HFreq pot is the one I'm thinking of, it doesn't change the screen much if at all but if I turn it, it causes a horrible high pitched whine the more I turn it.

It's hard to see in the pic, but I'm testing with a Galaga board. The indidvidual stars show up ok, but the ships and words and crap are the colored garbage.
 
Ghostnuke said:
No scope :(

If the HFreq pot is the one I'm thinking of, it doesn't change the screen much if at all but if I turn it, it causes a horrible high pitched whine the more I turn it.

It's hard to see in the pic, but I'm testing with a Galaga board. The indidvidual stars show up ok, but the ships and words and crap are the colored garbage.
Click to expand...

Um - if the stars look fine but the words and ships are screwed up, the board may be the problem...
 
modessitt said:
Um - if the stars look fine but the words and ships are screwed up, the board may be the problem...
Click to expand...

Hrmm. Could there be something between the board and JUST THIS chassis that would cause that?

I can put a known working chassis on this tube and plug it into this same board and it works fine. I did it about 2 minutes before I took the above picture.
 
I'd like to see a pic of the starfield looking good but the words messed up...
 
Ok.

Tried it with another board and it did the same thing. I couldn't get a decent picture of the starfield thing, you'll just have to trust me on that.
 
I haven't seen anything in this thread about checking to make sure R314 and R317 are 390-ohm and not the 4.7k-ohm that was mistakenly installed on some models...
 
modessitt said:
I haven't seen anything in this thread about checking to make sure R314 and R317 are 390-ohm and not the 4.7k-ohm that was mistakenly installed on some models...
Click to expand...

They're orange white brown gold, that's 390 yeah? I'm just about stumped here.

I did a deluxe kit on another chassis from the same batch I got from a customer and it's doing the same damn thing. The hfreq pot works better though, it ALMOST dials in but is just short of syncing properly.

Fuck me.
 
I wrestled with a similar situation and it was the damn sync on the board connector.. that got me pretty hot after 4 hours of tshooting the monitor. Check your harness?
 
It's possible the starfield looks ok because it's only individual pixels, and even if they are all scrambled across the screen they still look ok.

I just repaired a G07 last night and for a long time was trying to adjust things using a RGB modded Sega Genesis as a signal generator, only to find out the Sega Syncs on green and I was never getting any sync. It looked EXACTLY like your screenshot.

What I would do is get things setup so you can run the monitor with the game hooked up and then pull the sync wire only and see what happens. That's how I figured out the Sega wasn't giving a sync signal, because my jumbled garbage was identical with the sync line plugged in and unplugged.

Are you in desperate need of a test board? If you want to drive up to Santa Cruz I have a space Neo Geo MVS board you can borrow.
 
Anyone have any other ideas? I'm going to have to admit defeat otherwise. :(

I even reversed the sync mod to make sure, and it was the same.
 
I say we make it the object of some sort of contest. Each person who wants to work on it should pay to have it shipped, get a month with it, and if they can't fix it, give it up to the next person.

Everybody who fails should have to include a little prize in the package to go to the eventual winner. And then when it is fixed, Ghostnuke can pay to have it shipped back to him. Beats punting it over the garage.
 
kilgers said:
I say we make it the object of some sort of contest. Each person who wants to work on it should pay to have it shipped, get a month with it, and if they can't fix it, give it up to the next person.

Everybody who fails should have to include a little prize in the package to go to the eventual winner. And then when it is fixed, Ghostnuke can pay to have it shipped back to him. Beats punting it over the garage.
Click to expand...

I have no problems with this.

In the meantime...

I don't have a scope, and I'm not the best at interpreting schematics. What other components are part of the horizontal sync circuit? I'm down to spray and pray.
 
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