Asteroids 801 monitor - brightness/retrace issue

joeycuda

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My Asteroids project, I
-had the board repaired and burned in
-AR1 rebuild
-Big blue cap
-Recapped monitor chassis, including the 2 big filter caps
-Reflowed or replaced header pins on monitor stuff, reflowed stuff
-Frame mounted transistors, etc.

I did NOT replace the HV diode

Initially, monitor looked really good, but picture was shrunk a bit. After reconnecting wires for the test switch, I adjusted it out some, but not too large, with the box about 1/2" in/visible all around.

After it was on for about an hour, I noticed the screen getting brighter to the point of retrace lines and bright dot in center. Quickly dialed the brightness down. Seemed to brighten again some, turned it down. Keeping it dim enough that I wasn't seeing dots and retrace, it seemed down too low to look decent, and the text for the score and copyright at bottom seemed to flicker/flash.

Also, I noticed when objects pass across the screen, there seems to be a vertical "band" in the center where objects get slightly larger, then smaller as they pass through.

Where should I start - HV diode? Resistors? Thanks for any advice. I'd love to finish this (until something else breaks on it) and push it to the wall.
 
It sounds like you might have multiple issues. The brightness issues sound like something up with the HV cage. 801 cages don't have a single HV diode like 802 and v2000 cages. They have a voltage doubler (the big black square thing), plus a couple of VG2X high voltage diodes soldered to the board, so there's a little more going on in there.

The vertical banding is a little more concerning, as that's usually a PCB issue, and is typically due to a bad DAC, or other issue with the analog section. If that's the board I worked on, we probably should get that back in, and I can take care of it for you. I can take care of the 801 cage if you want, too. PM me and we can work something out.
 
It sounds like you might have multiple issues. The brightness issues sound like something up with the HV cage. 801 cages don't have a single HV diode like 802 and v2000 cages. They have a voltage doubler (the big black square thing), plus a couple of VG2X high voltage diodes soldered to the board, so there's a little more going on in there.

The vertical banding is a little more concerning, as that's usually a PCB issue, and is typically due to a bad DAC, or other issue with the analog section. If that's the board I worked on, we probably should get that back in, and I can take care of it for you. I can take care of the 801 cage if you want, too. PM me and we can work something out.

I forgot about the lack of HV diode. I'd rebuilt the monitor stuff so many months ago I forgot.

Will PM you. Thanks

Joey
 
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