Sanyo 20EZ B+ getting no reading...

bongoben

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Finally got around to testing the monitors in my PC-10 dual monitor cab tonight. Was a first for me. The bottom monitor has always looked good (after I did the cap kit when I got it) and the B+ voltage was right where it should be. The top monitor though has always been a bit dim, no matter how I adjust things it is always a bit dark/dull. The picture is all there it's just not bright enough. And if I brighten it way up on the flyback it gets really washed out. I haven't minded it too much since the top monitor only holds game info but I figure it's time to fix this one too. It has also had a cap kit.

The problem with the B+ on the top (crappy) monitor is that I got no reading whatsoever when I powered it up. Nothing moving. Disconnected Dokert's wire from the B+ pin and reinserted everything... checked the meter on a wall outlet to make sure I hadn't accidentally fried it, works fine. Checked that I had it on the correct setting... that was fine. Fired up the cab again and still nothing. Could there be a broken trace leading to the pin or something? Why would I be getting absolutely nothing on the meter? I've seen a ton of threads about what to do if you can't change the voltage via the B+ pot but nothing about getting no reading at all. The monitor still works every time I fire it up even if it dim... just couldn't get a B+ reading on it.

By the way, Dokert... thanks again for the B+ testing wire. I don't know how anyone would have done that without it.
 
When you say "wall outlet", does this mean you're plugging this straight into your wall? That's a big no-no.

If you have an image....B+ is doing something. If you had no B+, you monitor would be dead. You're not getting a good connection on the test point...or at the ground.

Edward
 
When you say "wall outlet", does this mean you're plugging this straight into your wall? That's a big no-no.

If you have an image....B+ is doing something. If you had no B+, you monitor would be dead. You're not getting a good connection on the test point...or at the ground.

Edward

No, by "Wall Outlet" I was referring to the fact that I tested my multimeter in the wall outlet to be sure it was working. It was. The monitor was always plugged into the power setup in the PC-10 cab. I also re-tested the B+ on the bottom monitor afterwards and that worked fine. I'm not sure why I'm not getting a good connection on the top monitor. I plugged Dokert's testing wire in as I am supposed to (and as I did on the bottom monitor) and ran the other line (black) to ground on the frame. And got no reading at all on the B+. May have to give it another run tonight and double check that everything is connected as it should be. If that doesn't work I may need to pull the chassis off of the frame to check the solder, etc.
 
Could be as simple as a cracked trace or solder connection at the test point. The B+ test point is nothing more than a metal pin soldered onto a track on the board. If it's cracked loose or the trace it's on has cracked, that could explain it.

-Ian
 
Could be as simple as a cracked trace or solder connection at the test point. The B+ test point is nothing more than a metal pin soldered onto a track on the board. If it's cracked loose or the trace it's on has cracked, that could explain it.

-Ian

That's what I was thinking. I'll take some time this weekend to pull out the board and check it out.

Thanks
 
You can also test the B+ at that big resistor beside the test point. If you're nervous about getting in there with a probe....just clip an alligator clip to it and run it out of the way.

Edward
 
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