WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

[proaudiosoft]

Hello all. I just Bought a Sega Sports Jam Arcade Machine with the intent on fixing it, and maybe later converting to a mame machine. I have done many in the past The sound is heard, but the CRT monitor does not turn on @ boot. When i took the back monitor cover off the machine I found a white ceramic resistor that was just laying in the metal monitor cover. After inspecting a minute I noticed r242 was missing from the neck board, and a black spot was left behind. My question is: should I just order a replacement resistor, or should I further investigate to find out what caused the resistor to fail (and/or fall off). I am just wondering if someone could point me in the right direction of what to check for? The monitor is a WGM2792-U0TS29K, the neck board is a p858. Resistor is 10w 1.5k . I will attach pic of neck board...

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

One more thing, someone suggested it fell off because of a cold solder joint. I tested the resistor (pic attached), its reading 1.333K Ohms. Is it within tolerance to reuse?

[stj]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

dont mame it, it's waste of a real machine.

the board has no heat marks, so it probably just fell out from cracked soldering.
put it back and check the rest of the joints - specially on large parts.

can you foto the factory sticker with the monitor details on it?

as it's NAOMI based, you would be better getting a NET-DIMM board and loading games from a raspbery pi or a pc as a multi-game cab
then you can put all this on it.

http://www.system16.com/hardware.php?id=723
http://www.system16.com/hardware.php?id=723

[stj]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

One more thing, someone suggested it fell off because of a cold solder joint. I tested the resistor (pic attached), its reading 1.333K Ohms. Is it within tolerance to reuse?

yes, it's probably fine.
strange though, naomi systems usually use a japanese monitor.

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

dont mame it, it's waste of a real machine.

the board has no heat marks, so it probably just fell out from cracked soldering.
put it back and check the rest of the joints - specially on large parts.

can you foto the factory sticker with the monitor details on it?

as it's NAOMI based, you would be better getting a NET-DIMM board and loading games from a raspbery pi or a pc as a multi-game cab
then you can put all this on it.

http://www.system16.com/hardware.php?id=723
http://www.system16.com/hardware.php?id=723

That is exactly what I plan on doing in the near future. (rpi3) I build bartop arcades for a living. I am attaching a pic of the monitor Sticker, if this is the one you want to see.

[stj]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

never seen that model number before.
you know it may be medium-res right?

i didnt mean use a pi to mame it, i meant use a pi to load games into the naomi unit.

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

never seen that model number before.
you know it may be medium-res right?

i didnt mean use a pi to mame it, i meant use a pi to load games into the naomi unit.

Yes, I know it is med res. I have Cloned sd cards with about 30 systems jam packed. No, I did not know you could run games from rpi to naomi unit. Thats awesome, how does that work exactly?

[budm]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

BTW, you should remove ALL those Brown/Yellow glues off the boards.

[stj]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

Yes, I know it is med res. I have Cloned sd cards with about 30 systems jam packed. No, I did not know you could run games from rpi to naomi unit. Thats awesome, how does that work exactly?

http://www.e-venturi.com/jamma/?page_id=1073

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

http://www.e-venturi.com/jamma/?page_id=1073

Thanks, I will check out when I get this fixed. I re-Installed the resistor, still no monitor glow. I am getting a little bit of smoke, like steaming off. It looks to me like its coming from the heatsink I circled in red (attached pic). Any suggestions?

[R_J]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

That is one of the drive transistors for the crt, (my guess is green) I suspect it is shorted and the extra current through the resistor melted the solder and it fell off.

[stj]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

check between the transistor leg for shorts, although i suspect you have other problems - the heater is not related to gun-drive.

[stj]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

what screen size is it, 27inch? 29inch?
controls - digital or pots?

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

Ok, thanks guys, gonna pull it and check it out now. It is a 27".... Digital, but I don't think I have the remote...

[stj]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

this may be it.

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

this may be it.

Yes, I think it may be one in the same. They both have the p858 neck board too apparently

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

check between the transistor leg for shorts, although i suspect you have other problems - the heater is not related to gun-drive.

The Transitor is a c3502e. it appears that it is a npn type from the data sheet i found online. E C B.

I get .682 base to emmiter, and .679 base to collector.

emmiter to base and collector to base shows open. from what I can tell its good.

what should I do from here?

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

Could IC201(video amp) cause the tube to not even glow if it failed?

[R_J]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

Do you have the any of the voltages on P203? +8 volts is for the heaters, if you don't have it, check back to the power supply on D811 and R858

[proaudiosoft]

Re: WGM2792 Arcade Monitor Resistor Burn Off On Neck Board *Need Help*

Do you have the any of the voltages on P203? +8 volts is for the heaters, if you don't have it, check back to the power supply on D811 and R858

Yes, I have +8.63v dc at 203, also 12.3v, and 69v but still no glow?