toei monitor

I think I might need one as well.....

On my CM-F20U it fires right up, then the picture shrinks and goes to a white line before fading away...

Hooked up the HV probe and the voltage is around 20kV then drops off to nothing.... if I turn it right back on I get almost no HV, if I wait about an hour goes to about 20kV then drops off to ziltch.....
 
I asked Peter in August if he ever thought he may commission reproduction flybacks for this chassis and his reply was, "No that one isn't even on the radar due to the lower volume of production numbers of that chassis as we have to justify many thousands of flybacks to even cover costs of reproduction."

So, alas, I believe all of us with 20" Toei's are screwed as if your flyback isn't dead yet, it probably will be soon.
 
I made a quick video of my situation:


You can see, once power is applied (isolated 100vac) I get 20kV at the anode. Then it appears that the picture starts to squish and the HV drops off to about 1kV. If I shut it off and reapply power, I only get about 1kV and no picture.

If I wait for it to "cool down" - about 30 to 45 minutes, the cycle will then repeat.

Is the HV drop causing the "squish" or is the "squish" causing the drop-off????
 
I think I might need one as well.....

On my CM-F20U it fires right up, then the picture shrinks and goes to a white line before fading away...

Hooked up the HV probe and the voltage is around 20kV then drops off to nothing.... if I turn it right back on I get almost no HV, if I wait about an hour goes to about 20kV then drops off to ziltch.....
That sounds like your monitor is going into shutdown. May not be a flyback problem.
Something is heating up and failing. Carefully inspect the board for suspect solder joints or cracks.
If none found, get a can of freeze spray/circuit cooler and use (just a little) of it on the suspected components to see if helps.
Based on your description of vertical collapse preceding shutdown, it may be a problem in the vertical circuit or in the components that supply power to the vertical circuit.
 
Excellent - I was hoping to hear something along those lines!

I'll get on this tonight and see what I find....

Thank you

Jeff
 
I have been going over this...... I always thought that only over-voltage would cause the chassis to shut down?

From the limited information I have on this model, it appears that the HV should be 27kV?

This chassis is only producing 20kV and then drops off to 1 - 2 kV.

I am still going to take a look but wanted to clarify the causes of shut-down.
 
OK.... just finished capping the entire chassis.....

Checked for broken traces and cold solder joints.......

Same results although it did seem to stay on a bit longer but that could just be my mind playing games with me.

I used freeze spray on all 5 IC's and on any and all transistors with no help and no change in the results.
 
Actually I just checked out my video in post #6 and there is no difference on how long the monitor produces a picture or HV.....

The capping of the chassis did not help in the slightest.......
 
Placed the order for a replacement UPC1358H - hopefully this will restore this chassis to working condition......
 
I think I am finally done with this,,,,,,,,,

Tried capping the entire chassis - no help

Found and repaired one or two cracked traces - no help

Re-flowed all pots - no help

Tried freeze spray on all of the IC's on the chassis - no help

Replaced the UPC1358H (vertical) - no help

Found loose fuse holders - replaced all three - no help

Every time I find something and repair thinking "this is gotta be it" I come up with the exact same issue......

As I do not have the schems for this model (TOEI CM-F20U (100vac)) I am at a loss of what to look for next - me thinks it's time to call it quits......
 
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