tm202g pulsating

InstantArcade

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I've replaced the crappy monitor in my original Universal Mr Do! with a TM202G that I've had hanging around.

The problem I have is that the monitor is pulsating in brightness, the pulsation speeds up then starts over, also it loses focus a bit as it's getting brighter.

Is this a known problem with the 202G? Does a Universal cab have an isolation transformer? Is that the problem?

Help?
 
Your Universal cab SHOULD have an iso. Why don't you check.

And you should have said you replaced a crappy monitor with another crappy monitor. :D

Was this Matsushita you put in recapped before doing so? if not, you should do that before wondered what's up with your monitor, and inspect it for cold solder while doing so. It might fix it, but even if it doesn't, you'll at least KNOW that isn't the problem.

And what was the "crappy" monitor you took out? Why not fix that one?
 
I took out a WG4600. It worked, but I couldn't ever get the video signal to show very well. It was always washed out and barely noticeable over the raster. I could get the raster nice and bright, but if I turn it down the game goes down with it. I remember the 202 looking pretty good when I pulled it a couple of years ago, but it's been sitting around since then, and I didn't check it on anything before I put it in the Do!

There's a big multi-core transformer in the cabinet, but I wasn't sure if it was an ISO too (although I've since confirmed this by looking at the schematics).

I *did* notice on the schematics that the monitor power supply is 100v rather than 120v, and I was wondering if that could have something to do with it.

Perhaps it's a completely unrelated problem. I will try and take a video of what is happening.
 
I'd do a voltage check of the monitor power connector to confirm if it's 100v or 120v. It might have something to do with it, as it might mean your B+ is running low...
 
The voltage was 98v. I noticed there's a voltage switching harness in the cabinet, it *was* on 120v so I plugged in the 110v harness instead, and now the monitor outlet reads 110v :)

The monitor was much better, but after it warmed up a it, I got the pulsating again. Perhaps I need to cap it (I've been avoiding it since the monitor is so filthy).

I think I'll go back to the 4600 and see if I can fix the video board in that instead. That monitor is already capped but super weak video. I know the tube is good since I tried it with a different 4600 video board some time ago and it looked great.
 
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