WG 4900 Troubleshooting in process. Help needed

MC35

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I previously posted help request with this monitor when it was in my Ms Pac machine. I finally pulled it out of the cabinet and put it on my bench for the ease of troubleshooting. I am running it with a Golden Tee 3D machine. I believe I have isolated it to the vert out section. I have checked every Oscilliscope point listed in the Manual, and several dc measurements on various transistors. The attached picture is what the screen is doing, (disregard the Ms. Pac Bezel.) The biggest 2 problems I have found is the collector on Q302 (even though the schematic calls it Q203) is about 15 volts higher than the manual calls for. R313 is measuring 470 ohms. TP 82 (wire going into green deflection yoke) appears to be overdriven and inverted.
Any help putting me in the right direction would be awesome.
Thanks
 

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after verifying the video wires are pinned out correctly and connected, try adjusting your holds.( v hold, h hold, do h first)
 
Definitely looks like a sync issue. I had my 4900 looking like that the other day when I hooked up coors light bowling and ikari warriors
 
This has had a cap kit installed. The pots don't bing the sync in at all. I suspect more the Vert out, section but am open to any suggestions. There were a few things added to the board from the previous owner that I can't figure out why, (i.e. R222 was bypassed by a jumper). The biggest problem in my opinion is the collector reading 15 volts high on one of the vertical transistors.
I'm willing to o-scope or measure any suggestions.
Thanks
 
The pots don't bing the sync in at all. I suspect more the Vert out

That looks like a textbook sync issue. Check your sync connections and polarity. IIRC, MsPacMan is negative composite sync. Try connecting it to H-sync only.
 
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Yoke Plug

OK... I want you to try this. Discharge the 4900 chassis. Flip it over and look at the solder joints for the main coil plug. I've seen this soo many times. The 4900's are notorious for broken solder traces at the scan coil plug on the bottom of the pcb. Use a meter to make sure that the traces aren't broken. That fixed mine. I get a horizontal collapse with this issue. If this isn't it, I'd suspect the horizontal pot went bad.
 
That looks like a textbook sync issue. Check your sync connections and polarity. IIRC, MsPacMan is negative composite sync. Try connecting it to H-sync only.

I have tried different varations of sync connections and polarity with the same results. The attached picture is actually the monitor mounted in my Ms Pac cabinet, but connected to Golden T 3d. I have since removed the monitor and put it on my bench for ease of troubleshooting. It is, however giving the same results as in the picture.

OK... I want you to try this. Discharge the 4900 chassis. Flip it over and look at the solder joints for the main coil plug. I've seen this soo many times. The 4900's are notorious for broken solder traces at the scan coil plug on the bottom of the pcb. Use a meter to make sure that the traces aren't broken. That fixed mine. I get a horizontal collapse with this issue. If this isn't it, I'd suspect the horizontal pot went bad.

Not sure where the scan coil plug is but the chasis is out of the cabinet and wired on my workbench. I have briefly looked at the solder joints on the bottom prior to this. The horizontal pot is definately something I can remove and check the value on.
Thank you, now I'm anxious to check it out.
 
The yolk plug

I meant the yolk plug plugs into male header pins on the chassis. Flip over the chassis and check continuity from the header pins to make sure that there are no broken traces. These are notorious from breaking away from the traces.
 
o.k. Solder joints look good. One of the vertical output Transistor has an inverted signal on the emitter and the collector output is reading 95 volts vs. 80 according to the manual. Any thoughts on why the emitter is inverted and the output is too high.
 
o.k. Solder joints look good. One of the vertical output Transistor has an inverted signal on the emitter and the collector output is reading 95 volts vs. 80 according to the manual. Any thoughts on why the emitter is inverted and the output is too high.

I don't know for sure, but I would check transistor Q303 and the diodes at D302, D303 and ZD301. Also check the other resistors in that area. Did TP-81 look okay on the scope?
 
I previously posted help request with this monitor when it was in my Ms Pac machine. I finally pulled it out of the cabinet and put it on my bench for the ease of troubleshooting. I am running it with a Golden Tee 3D machine. I believe I have isolated it to the vert out section. I have checked every Oscilliscope point listed in the Manual, and several dc measurements on various transistors. The attached picture is what the screen is doing, (disregard the Ms. Pac Bezel.) The biggest 2 problems I have found is the collector on Q302 (even though the schematic calls it Q203) is about 15 volts higher than the manual calls for. R313 is measuring 470 ohms. TP 82 (wire going into green deflection yoke) appears to be overdriven and inverted.
Any help putting me in the right direction would be awesome.
Thanks

Isn't Golden Tee 3D a medium res game? If so, you will never get the picture right on a standard res 4900.
 
Isn't Golden Tee 3D a medium res game? If so, you will never get the picture right on a standard res 4900.

I believe 3D is standard res like GT98 GT99 and GT2k. They went with switchable res in 2002-2006 Fore's. When they went to GT Live, it was VGA, but they had an interface board to use different monitor res's...
 
BTW - your problem is on the horizontal sync line, although a lack of video ground can cause this, too...
 
I don't know for sure, but I would check transistor Q303 and the diodes at D302, D303 and ZD301. Also check the other resistors in that area. Did TP-81 look okay on the scope?
I have checked all the resistors in this area. one did lose value. Diodes 302 and 303 are fine. TP 81 is where the inverted signal is, which is also the emmitter of the same transistor that has a high collector.

BTW - your problem is on the horizontal sync line, although a lack of video ground can cause this, too...

I admit I am a newbie and I can honestly say I don't know much about res but the monitor that is currently in Ms. Pac came out of my Pole position. I tested that on Golden tee and it worked great, so I suspect that this monitor will work with Golden Tee. With the problems I am having in the Vert Section I have a hard time focusing on the Horizontal section. But I am learning and will take any advice given. Where should I be looking on the Sync line.
 
I admit I am a newbie and I can honestly say I don't know much about res but the monitor that is currently in Ms. Pac came out of my Pole position. I tested that on Golden tee and it worked great, so I suspect that this monitor will work with Golden Tee. With the problems I am having in the Vert Section I have a hard time focusing on the Horizontal section. But I am learning and will take any advice given. Where should I be looking on the Sync line.

Adjust the horizontal hold pot...
 
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