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Bad A Billy
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Easy monitor question...
#308266 - 05/04/13 05:18 AM


Any suggestions would be welcomed. Monitor diagnosis & repair is beyond my limited knowledge.

Story: Took chips out a game (small bartop cab) to dump. Stored in garage until this week when I put the chips back in. Fired it up and nothing. Re-seated chips still nothing. PCB leds on. Checked wiring and voltages - all OK. Open the back up and there is just a small whisp of smoke(REAL small)... Finally track it down to the seal between where the guns go into the back of the tube(?)

I imagine it's dead...Is it repairable??
Also, shouldn't the game still boot(w/sounds) even with a bad crt?

I also have an old Pole Position monitor that works(?) Turns on and off but to a white screen, it can be turned down to dark. Haven't got the board working yet so I haven't tried another board with it yet. Any ideas on this one?

Thanks for the help guys...



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italieAdministrator
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Re: Easy monitor question... new [Re: Bad A Billy]
#308270 - 05/04/13 08:51 AM


> Any suggestions would be welcomed. Monitor diagnosis & repair is beyond my limited
> knowledge.
>
> Story: Took chips out a game (small bartop cab) to dump. Stored in garage until this
> week when I put the chips back in. Fired it up and nothing. Re-seated chips still
> nothing. PCB leds on. Checked wiring and voltages - all OK. Open the back up and
> there is just a small whisp of smoke(REAL small)... Finally track it down to the seal
> between where the guns go into the back of the tube(?)

I'm not following with the term "seal". The neck isn't seamed. Are you saying the smoke came from the neck board, or is the tube cracked? Or are you referring to the plastic guide that keeps the neck pins?

If the smoke came from the glass of the neck your tube is shot/cracked (never personally seen smoke come from the tube). If the smoke came from the neck board, there is hope. Pull the neck board and start looking at resistors/transistors/caps for damage.

> I imagine it's dead...Is it repairable??
> Also, shouldn't the game still boot(w/sounds) even with a bad crt?

Yeah, dead monitor wouldn't affect PCB voltages.

> I also have an old Pole Position monitor that works(?) Turns on and off but to a
> white screen, it can be turned down to dark. Haven't got the board working yet so I
> haven't tried another board with it yet. Any ideas on this one?

Possibly the game board, possibly the monitor chassis. Too little info to tell.



Bad A Billy
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Re: Easy monitor question... new [Re: italie]
#308285 - 05/04/13 11:56 PM


Thanks Italie...
Here are pix of the 1 I know worked fine...

http://bit.ly/102RfFT

What I mean by "seal" is the white ring that clamps together(Closest to the front of the cab). It's also just a tiny amount of smoke. The only reason I finally saw it was because I left it on for about 10-15 mins and opened the back panel up. It had built up enough to be visible. The pcb on the rear looks to be OK,same as all the rest. Could it just have been dirt from sitting and/or being that old? Seems to be original and from ~88. No signs of ever being rebuilt. The screen still seems to come up when turned on and gives the white to the center when turned off.

I'm thinking game board. Your thoughts?



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italieAdministrator
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whhhhhOOPPP....whhhooooOOOOOP....... Danger Will Robinson.... new [Re: Bad A Billy]
#308287 - 05/05/13 12:29 AM


Resisters on the yoke, ohhh Christ. Get your electronic repair hat on.

The area you are looking at is the purity rings (small tabs sticking up), followed by the yoke (big coil thingy). That whole contraption is removable, and slides right over the neck. The yoke is what "bends" the electron beams coming off the guns (or into the guns, depending on your point of view). Impedance matching the yoke to the chassis is important to get a proper bend on the beam. The resistors in that image were most likely put there to allow that yoke to work with a non-factory chassis.

The purity rings are a "fine adjust" with the same basic purpose, only more of a permanent offset.

So that pic is the monitor in question that smoked? I'm a little confused as to which issue we are looking at. If yes, I'm guessing the smoke was either dust off the yoke, or one of the "rig-it" resistors baked. Troubleshooting is going to be a process at this point, you'll need a multi-meter at the very least. A known working game PCB would be of great assistance as well, but not entirely necessary. We will have to establish exactly what the monitor is doing now, images are a plus, as are any part numbers on the tube and chassis (monitor PCB). If it is coming up without a burning or ozone smell, that's a plus. I'd start by measuring the resistance across the yoke (MONITOR POWERED OFF), and making sure the chassis is a proper match.





> Thanks Italie...
> Here are pix of the 1 I know worked fine...
>
> http://bit.ly/102RfFT
>
> What I mean by "seal" is the white ring that clamps together(Closest to the front of
> the cab). It's also just a tiny amount of smoke. The only reason I finally saw it was
> because I left it on for about 10-15 mins and opened the back panel up. It had built
> up enough to be visible. The pcb on the rear looks to be OK,same as all the rest.
> Could it just have been dirt from sitting and/or being that old? Seems to be original
> and from ~88. No signs of ever being rebuilt. The screen still seems to come up when
> turned on and gives the white to the center when turned off.
>
> I'm thinking game board. Your thoughts?



Bad A Billy
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Re: whhhhhOOPPP....whhhooooOOOOOP....... Danger Will Robinson.... new [Re: italie]
#308304 - 05/05/13 04:47 AM


Thanks again...
That was the one that smoked
When I get some free time I'll go through what you mentioned and/or try a good pcb with it and let you know.

Thanks so far.



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