Sanyo ez b+ 122v

mgb

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Kind of a vague dumb question, but I'm hoping for something obvious that I missed. I recently worked on some machines for a guy. His Mario Bros monitor was squished up top.
First thing I figured was check B+ on the monitor. B+ would not adjust over 90v. So I figured lets give a cap kit. While doing the deluxe cap kit, I also replaced the b+ adjustment pot (5k, from Bob Roberts)

After doing the cap kit, I brought it to check it out on some one elses Donkey Kong because I don't have a 100 volt power source. I didn't hook up the video and all that (Though I should have) But I plugged it in and metered the b+. It was at around 107. I went to give it a small tweak to 108 but it just kept slowly rising to 122v or so and would not adjust down. I really wanted to get this setup before going back to the owners house because its a good length drive. I know I should have plugged it all into the donkey kong for check out, I don't know why I didn't.
Any ideas would be very helpful. I suppose it could be the power filter cap, it just seems weird that it wasn't high before th cap kit.
 
i would re-flow the solder on the IC601 and Q901 that make up the regulator. and i would also replace the filter cap.

also the B+ pot is a 10K pot not a 5K that may also have an impact on your problem.

Peace
Buffett
 
says in the sanyo manual 10K that's here i get my info.

i have used nothing but 10K pots for all my rebuilds and have zero problems

Peace
Buffett
 
I double checked the schematics and the b+ (vr601) is definitely specced as 5k.
 
Hummmm. I'd love to get a definitive answer on this.

I've never replaced the b+ pot on my Sanyo 20EZ, but I plan to based on the problems many people seem to have with them.

I have a Sanyo 20EZ Schematic that shows clearly a 5K pot.

I also have an Atari manual from 1987 for a "19" Standard Resolution Display"
In that manual there is a parts list for Sanyo 20-EZV and 20-Z2AW. The list shows a 10K pot.

To further add to the confusion, the schematics that are included in this manual shows a 5K pot!

Attached are the images from the 20-EZ schematics and the 20-EZV manual part list.

I plan on using whatever Bob sells me, but it would nice to know for sure. What would be difference between a 5K pot and a 10K pot? How might that make a difference in its effect on the monitor?
 

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I have used the 5k pot from Bob Roberts in the past and it has worked fine.
I'm a little surprised to hear of a 20 ez showing in an Atari manual. I have only seen them in Nintendos, although I guess they used them in others, that's why they have inverter boards.
 
Test a factory pot I had and got 5k on it to. I wonder if the 10k pot helps with this problem though. Cause I replaced just about everything with my chassis and it didn't solve this problem. Beats me though.
 
I doubt that would fix. If its supposed to be 5k, putting in a 10k is just gonna make it more touchy on adjustment. B+ being high is an indication of problems elsewhere, like in the horizontal circuit.
 
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