G07 cbo oddball sync mod?

tron guy

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I am working on a "working" g07 chassis, though apparently it has been finicky.

I plug it into my wacko prior to doing any work and I get an odd side-scrolling lack of horizontal sync.

The width coil is about toast and the horz freq pot does nothing.

On the bottom I find this (pic below), poorly soldered with an jumper connecting pins J2-j3 and R301.

Not having an arkanoid, I'm not sure if I should leave this jumper or not?
 

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Ok rebuilt the whole thing. Cap kit, flyback, width coil, fr401, R908, pot kit. Reflowed solder everywhere.

Same thing.

Clearly that jumper ruins the sync with wacko. I guess I have to assume that instead of modifying the wiring(in arkanoid), they modified the chassis?
 
That jumper is clearly NOT original. I'm wondering if the jumper was there due to a broken foil trace? If so, I would meter out the traces in that area to be sure of good continuity. That jumper might be somebody's hare-brained idea to beef up the negative sync circuit.

It looks like that chassis has never had the negative sync mod either.

Double check resistors R314 and R317. They should be 390 ohms. The factory sent out alot of chassis with the wrong resistors installed. If you find 4.7k resistors installed in those locations, then they must be replaced with the correct 390 ohm ones.
 
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That jumper is clearly NOT original. I'm wondering if the jumper was there due to a broken foil trace? If so, I would meter out the traces in that area to be sure of good continuity. That jumper might be somebody's hare-brained idea to beef up the negative sync circuit.

It looks like that chassis has never had the negative sync mod either.

Double check resistors R314 and R317. They should be 390 ohms. The factory sent out alot of chassis with the wrong resistors installed. If you find 4.7k resistors installed in those locations, then they must be replaced with the correct 390 ohm ones.

I have that value resistor and can replace them if necessary. The mod is a hack job.
I did the curl mod suggested with a 22uf cap. I think I've seen the neg sync mod in 1/2 of the g07's I work on.

So in your opinion, Ken, should I remove that hack mod of the sync pins, get it to work perfectly in my wacko, and take it from there when testing in the arkanoid it came out of?
 
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yes remove that HACK.

you can do that with the 2 sync pins if you need to make it composite sync, but not for any other reason.

Peace
Buffett
 
yes remove that HACK.

you can do that with the 2 sync pins if you need to make it composite sync, but not for any other reason.

Peace
Buffett

this, I've run G07s on multiple JAMMA games and never did these Bob Roberts sync mods. you just bridge sync to vertical and horizontal, done.
 
Done, thanks guys. Once the rain slows down I'll test it. My "test bench" is my wacko, and it's facing the outside of my garage.


Yeah I went and tested it. Perfect, as I thought it would be.
 
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