Sanyo 20EZ Cannot Adjust B+

Michael Roma

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My turn for a 20EZ thread...

I had a similar problem as some other people here not being able to adjust the B+. It is stuck at 88v and adjusting the pot does nothing.

After reading the recent posts I replaced the filter cap (C606), IC601, the current limiting transistor (Q901) and the B+ pot (VR601) to no avail.

What is there left that could be causing this?

- Mike
 
Check the traces from point to point for continuity in the 600 section. Also look for solder bridges and solder splash.
 
Finally had a chance to work on this...

I tested continuity between everything in the 6xx section and all checks out. I checked for shorts, solder spash, etc and didn't see anything. I also reflowed the solder on everthing in the 6xx section just for SnG but still end up with a B+ that cannot be adjusted.

Here are some high-res pics... Is there something that sticks out to anyone that could be the culprit?

sanyochassis_wave01.jpg


sanyochassis_wave02.jpg


- Mike
 
I'm curious, does it work at 88v at all ? When you adjusted it did you crank the brightness pot to full and was the brightness on the fly cranked up ?

I just went trough a similar issue with one and my problem ended up being a cold solder on the flyback, I couldn't get more than 58v on and I thought it was the B+ pot or something related to that area but once I fixed the flyback and plugged it in I instantly had 128v and was able to adjust it down.

You'll notice when you adjust one that works that the voltage will go up and down with the brightness pots.

You might know this stuff already but I didn't and found it out when messing with mine, I wondered why the procedure said turn the brightness up to full.
 
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I've had the same problem for almost two years. the screen is wavy like the flag. I put up with it for all this time but now I am digging into it. I have the exact same b+ reading and can't get it to change. Hmm...
 
The B+ does change (albeit minimally) when I adjust the brightness. The monitor does work and displays a nice picture it is just wavy, wavy, wavy!

As for the c606... I pulled it from a donor chassis.

- Mike
 
Sorry, but some things just can not be trusted coming off of a donor chassis.

I just replaced a 7000 fly with one from a known working donor chassis, and although the monitor came up it just wouldn't focus good enough for me. Put a brand new fly in, and it works awesome.
 
I'm having the same problem here. I've got a new flyback from Arcade Cup. Only thing I haven't done that Roma done is replace IC601. Did you ever resolve this problem?
 
I never fixed it... This thing sat on my work bench for quite a while. I got so frustrated and lost patience and desire.

Sanyo 20ez. 1
Mike Roma. 0
:mad:

- Mike
 
Hmm seems alot of people have this problem and no fix. Could it be a resistor in the 600 area? Or would that be a waste of time testing em all?
 
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