g07 sync issue. - space invaders mod

cleverlyj

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I gave up on the v1000 and put a g07 in my space invaders. did the color mod and got everything working. problem is, i can't get the monitor to sync.

with the sync hooked up to the pos sync in the j1 connector, i get a pic that is great but i can't get it to stop rolling. the closest i can get is an extremely slow roll. after searching on here, i saw a thing and link to bob robert's page, and tried hooking up the sync to the negative sync.

that got the rolling to stop, however any time during attract mode when the invaders and playfield are on the screen, or during gameplay, the screen looks all crinkled, like instead of everything being straight lines, its more like /\/\/\/\, if you get what i mean.

so here's the details -

the sync wire off the board is connected to a separate molex connector with two pins on it. should there be one for both h and v sync, or just one or the other?

haven't checked the b+ yet.
i don't have a video ground plugged into the j1 connector. - that i wasn't sure about. should i do that and connect it to the chassis ground or what?

haven't done those last few parts, as getting the monitor and chassis adapted into the cabinet due to the different size took forever. anyway, if anyone has a suggestion, let me know. flipping the sync to the negative is the closest i've gotten at this point.
 
Does the pic look like this?

Photo-0011.jpg
 
Does the pic look like this?

Photo-0011.jpg

yeah, just like that but severe, like times 100.

and to add -

set the b+ at 120.
added the video ground.

still getting the same. i get a steady but distorted pic with neg. sync, whether h or h+v, and i get a rolling pic on pos sync. the adjustment is so slight i try to get it even, and it'll start creeping along rolling after a few seconds. unless there's some trick to get the pic fixed with the negative sync, i'm thinking replace the pot on the chassis.

also, i have read about 'jumpering' the negative sync together. will that do anything?
 
For a G07, you'll need to jumper the sync between negative vertical and negative horizontal if the sync is negative.

As for the squiggles, if they persist after the sync jumpering, remove the anode cup (after discharge), clean the inside of the cup and around the hole (after discharging again), then reinstall the cup - rotating it so that the anode wire is as far away from the yoke as possible...
 
so by jumpering it you're just meaning tying it together with one wire, right? as in a jumper wire? and just leave the sync wire hooked to pos?

cause the wire i presently have has the sync going into a 'y' 2 pin molex connector, which is how i have the sync connected with the negative sync, one sync wire connected to the h and v, and that's what was giving me the squiggles.

i'll try cleaning the anode in a minute and get back to you, mod.
 
allright. cleaned the anode/hole and also turned it to get the anode wire away from the yoke. still no change there. i'd post a pic but my camera battery is dead and charging, so i'll do that tomorrow.
 
allright, so here's a pic of what it looks like. the first is a pic of the playfield. it looks really distorted. the second is the insert coin screen. it is still distorted a bit but not as bad as the playfield screen looks. and this is with it hooked to negative sync. i get a good but rolling that doesn't stop picture with pos sync.

and also, just to verify, when bob roberts talks about jumpering the negative sync on a g07, does he mean connecting the one sync wire to both h and v neg sync or using positive sync with a jumper just connecting the two negative sync pins together?

DSC03014.jpg

DSC03015.jpg
 
allright, so here's a pic of what it looks like. the first is a pic of the playfield. it looks really distorted. the second is the insert coin screen. it is still distorted a bit but not as bad as the playfield screen looks. and this is with it hooked to negative sync. i get a good but rolling that doesn't stop picture with pos sync.

and also, just to verify, when bob roberts talks about jumpering the negative sync on a g07, does he mean connecting the one sync wire to both h and v neg sync or using positive sync with a jumper just connecting the two negative sync pins together?

DSC03014.jpg

DSC03015.jpg

Damm now the aliens even look like sperm.
 
As far as your sync goes - if you have only one sync wire coming from the board, then it should either go to BOTH positive sync pincs or BOTH negative sync pins - but it shouldn't go to both positive and negative at the same time....
 
As far as your sync goes - if you have only one sync wire coming from the board, then it should either go to BOTH positive sync pincs or BOTH negative sync pins - but it shouldn't go to both positive and negative at the same time....

ok, so i have that correct then. as far as the distortion on negative sync, is there anything you think i can do about that? or should i use the positive sync and try replacing the pots to see if that fixes the rolling?

the only thing that's weird is that the sync adjustment perfectly stops the rolling on the negative sync. meaning that when i adjusted it initially, i got the knob turned to a spot where the picture just rolled into place and stopped.

however, on the positive sync side, i have to keep bumping the pot each way to 'nudge' the screen into place and then it will start creeping into a slow roll after 20-30 seconds.
 
ok. so, i checked r314 and r317 per an old post by ken layton to make sure they were right - they metered 388 ohms. so ok there. put the sync back to positive and pushed against the v hold pot while adjusting, made it worse.

so, down to the local electronics shop to get a 10k pot (per the scat) to replace it with tomorrow and we'll see where that goes...
 

yeah. but it just says sync - never really says what sync to hook it to. brent hasn't been on here for like a month, so i didn't bother to pm him. but, if anyone that has also done the color mod wants to chime in on what they used sync wise, i'll try it. in the meantime, i'm gonna replace that trim pot tomorrow and see what that does.
 
BTW - have you connected this G07 to a regular game lately to make sure it syncs that way? It could be something related to the chassis, and not to the wiring...
 
no, i have not. and btw, will a k4900 chassis work on a tube from a g07, without any modifications? i have a spare recapped one lying around i was thinking of trying.
 
allright. replaced the pot today. still the same thing. are there possibly any screen adjustments that can be made to fix the distortion on negative sync issue?

also, with the rolling on positive sync, is there possibly a different value pot i can go with to give me a finer adjustment so i can stop the roll? the pot that it calls for is a 10k.
 
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