G07 vertical roll-roll-roll HELP !!!

[galaxian]

Guys,
         I have a G07 which I am putting in a Jamma cab. I am unable to get the vetical sync locked in.
I have connected J2 and J3 together and connected to my sync signal - is this the correct way to do this ?

I have tried 2 different working boards (they work on my Hantarex 900 anyway) - a NeoGeo 1 slot and Beastorizer.

Searching the forum I tried a number of things before I posted this. I replaced the X302 and X306 and IC501 as suggested on the G07 flowchart - no difference.

I then came across the incorrect resistor at R314 and R317 - R317 was correct, but R314 had the 4.7k mounted, BUT someone had the correct 390 ohm soldered under the board in parallel ! Removed the 4.7K and put the 390 in the correct place - no difference.

The  V-Hold pot does make a difference, there seems to be about 4 images rolling, and I can lock the images so any displayed text can be seen 4 times on the screen.

Any pointers where I can go from here ?

Apart form this, the display is nice and bright, sharp and all colours seem to be fine.

PS I have recapped virtually all the electrolytics too.

Thanks,

Colin.

[grantspain]

you have def got one of two probs,either the sinc connection is wrong on the signal input or your frequency is set incorrectly.i am afraid i dont know much about your particular chassis but if you post the signal input pinout we should be able to attain the correct connections,also is the g07 auto frequency or set by a plug/jumper.

[galaxian]

OK, problem resolved, I think I may be looking at two issues here.
After lots of messing around I connected a faulty board (it displays garbage-don't care if I destroy it) and the picture was stable !!!!!!

I tried my Beastorizer and Neo Geo, and both boards would not sync, mmmmmm.

I had originally tried a vertical game in the cab Fixeight, and it would not sync, lets try again - bingo !

There was definitely a problem as this board would not sync before, so either the replacement transistors or the HA video chip must have been duff. As a bonus, this board showed the 'curling' problem on my Hantarex, and at the operators arcade where I bought it, but on this monitor it is perfect.

Just means some boards may not work.

I may just put it back in the old centipede cab where it came from and restore it. (as long as the boad sync's up !)

Regards,
Colin.

[Ken Layton]

Remember that resistors R314 and 317 may have had the incorrect resistors installed from the factory. Quite a few got out of the factory before the problem was discovered. These two resistors are supposed to be 390 ohms quarter watt, but the factory mistakenly put in 4.7 k ohm ones instead.

Are you mixing gameboards of different sync types?

Centipede used seperate POSITIVE sync going to the six pin connector on pins E5 (vertical) and E6 (horizontal).

Most modern games use composite NEGATIVE sync going to both J2 and J3 on the 3 pin connector.

[galaxian]

Ken, I have both pins (J2+J3) jumpered and connected to the composite on these boards.
The monitor was not working when I got the cab, so I made a temporary loom to test it with my jamma stuff.

R314 had the 4.7k mounted, BUT someone had the correct 390 ohm soldered under the board in parallel ! Removed the 4.7K and put the 390 in the correct place. R317 had the correct component installed..

Regards

Colin