Monitor help please

[Silvercity]

Good evening, could anyone give me some things to try to get the colours to combine? When I twiddle the little knobs on the neck board the colours change but are just one colour at a time. Any help much appreciated. Complete novice. Super happy to even have a picture on the screen 😊
Thanks
Update: screen just turned off after 30 minutes play. Will try turn on in the morning.

 

[thegreathopper]

I would start off by removing that JNX adaptor, you shouldn’t need that with a 1 slot on a jamma cab.

Its also really weird the game plugged in is Super sidekicks and the game playing looks to be KOF 1997.

 

[Silvercity]

Thank you. The cabinet used to have a multistot and i was under the impression the jnx stops you burning out something to do with mono and stereo sound? I will try without, as it can't hurt for a little while?

Yes, I was playing KOF 98 but then i tried super sidekicks just to see how it looks.

Any other advice Chassis related?

 

[big10p]

The pots on the neck board are to adjust individual RGB cut-off and gain. They'll need recalibrating. What was the picture like before you started twiddling the pots?

 

[thegreathopper]

Thank you. The cabinet used to have a multistot and i was under the impression the jnx stops you burning out something to do with mono and stereo sound? I will try without, as it can't hurt for a little while?

Yes, I was playing KOF 98 but then i tried super sidekicks just to see how it looks.

Any other advice Chassis related?

Oh yes if it had a 4 slot you will need that adapter or move 1 wire on the harness but that may be for the future.

I would press the test button on the Neo Geo and see what your RGB and white look like.

 

[Silvercity]

The pots on the neck board are to adjust individual RGB cut-off and gain. They'll need recalibrating. What was the picture like before you started twiddling the pots?

Thank you, the screen has appeared to be dead since I bought the cab, no neck glow. Then last night I wiggled the neck board and the screen came on in green. So I twisted the pots and from they I could change the colour one at a time. I then had it running for about half an hour and when I was playing the game (in blue) the screen appeared to quickly collapse with a horizontal white line that quickly disappeared and now no screen or neck glow again.

 

[big10p]

I would make sure the neck board is fully pushed onto the tube, and that the remote board is connected securely. Do this with the monitor off. If no luck with this, the chassis probably needs servicing.

 

[Silvercity]

I would make sure the neck board is fully pushed onto the tube, and that the remote board is connected securely. Do this with the monitor off. If no luck with this, the chassis probably needs servicing.

Yes will do. Any components that are more likely to be related. Was thinking of checking the parts on the neck board. Any chance of a crash course 😉 how to check the 3 legged thingies? Thanks again

 

[big10p]

Yes will do. Any components that are more likely to be related. Was thinking of checking the parts on the neck board. Any chance of a crash course 😉 how to check the 3 legged thingies? Thanks again

Not really as all colours look like they're working. There is another pot on the neck board that has the plastic adjuster missing in your pic.

 

[Lurch666]

Are you turning one pot up,getting colour then turning the same pot down and adjusting the next pot?

 

[gunblade]

do you have multimeter?

 

[gunblade]

check r12 on neck card, it should be 1R5
also might be worth checking r40 10R

 

[Silvercity]

check r12 on neck card, it should be 1R5
also might be worth checking r40 10R

Yes and thank you. will do

 

[Silvercity]

check r12 on neck card, it should be 1R5
also might be worth checking r40 10R

can’t see an r12?

 

[Silvercity]

can’t see an r12?

Just found it 🤔

 

[Silvercity]

Just found it 🤔

Tested and seem good 👍🏼

 

[gunblade]

ok so you see you have 200v video b+ and you have cut offs, whats missing is parts of the video signal - all very odd
only time i have seen that fault on polo is the 1r5 resistor
out of interest if you remove that jamma adapter does it make any difference, have you tried a different game board?

do contrast and brightness pots work on remote board?

otherwise could be an issue on the lm1203n ic on the neck card

 

[gunblade]

hang on, have you checked for any bad solder joints on the crt socket inclluding the socket ground pin

 

[Silvercity]

hang on, have you checked for any bad solder joints on the crt socket inclluding the socket ground pin

I will check this. Thanks for the advice.