Build Your Own Arcade Controls Forum

Main => Monitor/Video Forum => Topic started by: axl1826 on February 27, 2012, 03:09:07 am

Title: WGM-2775 No Color
Post by: axl1826 on February 27, 2012, 03:09:07 am

I have a WGM-2775 out of a San Francisco Rush the Rock that is not displaying any color what so ever I have tried several things so far.
-Replaced the tube
-Re-soldered the connections on the flyback
-Replaced the traces on the flyback

But all of this has not fixed the problem  :banghead: do I need new transistors? I am at a loss, any input would be appreciated. I am new to this hobby, I successfully built my own MAME Cab and now my buddy wants me to fix this Rush the Rock, used this forum a lot to build my MAME so I thought I would come here for help.

Title: Re: WGM-2775 No Color
Post by: grantspain on February 27, 2012, 04:14:45 pm

on the neck card is there a lm1203n ic?
also i did have the same issue on a u5000 chassis a few weeks back and it took me ages to find the problem,cause was R811 open circuit(100k 0.5 watt resistor)
I can't find the schems for the u2000 chassis but i am guessing its the same chassis without the 24khz support circuit

Title: Re: WGM-2775 No Color
Post by: Q*Bert_OP on February 27, 2012, 11:49:48 pm

R811 (75K ohm, 1/2 watt resistor) is likely the cause of no color. This usually goes open. The IC on the neckboard rarely fails.

Just to clarify, you're getting a picture in black and white, right?

Title: Re: WGM-2775 No Color
Post by: axl1826 on February 28, 2012, 12:37:53 am

@ grantspain yes the is an IC LM1203N

@ Q*Bert_OP yes I am talking about a black and white picture, I just tested R811 and it is showing 1.45M Ohms of resistance so I will swap it out and let you know what I find from there.

Thanks for your help guys!

Title: Re: WGM-2775 No Color
Post by: axl1826 on February 29, 2012, 07:24:27 pm

I replaced the suspect resistor and not a whole lot changed unfortunately now the picture looks washed out with a yellow border.

Title: Re: WGM-2775 No Color
Post by: grantspain on March 01, 2012, 06:05:27 pm

do any colour pots or the contrast pot have any affect on the picture at all

Title: Re: WGM-2775 No Color
Post by: axl1826 on March 01, 2012, 08:22:13 pm

All changing the pots seems to do is make the picture washout even more it just gets brighter doesn't matter which color i adjust all the same.

Title: Re: WGM-2775 No Color
Post by: grantspain on March 02, 2012, 02:15:06 am

check resistors on remote card

Title: Re: WGM-2775 No Color
Post by: axl1826 on March 02, 2012, 03:57:41 am

All the resistors on the remote board are within spec

Title: Re: WGM-2775 No Color
Post by: grantspain on March 02, 2012, 02:36:53 pm

apart from a pcb track broken on the neck card or all your colour drive transistors are faulty I can't really think of anything else-highly unlikely all the drive transistors would be shot though

Title: Re: WGM-2775 No Color
Post by: axl1826 on March 02, 2012, 08:25:22 pm

I'll check all the tracks again and see what if i find anything, thanks for your help!