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Author Topic: Sanyo 20 EZ 13" Unadjustable B+ No Raster  (Read 1466 times)
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mrdude
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« on: January 11, 2015, 10:04:31 pm »

Ok. So. I've got a 13" 20 EZ out of my cocktail. I've gone through with the help of some other forum members on here the troubleshooting guide and flow chart for this monitor. I just want to narrow down with a new thread what has been done. Yes, this is the one I have been working on for a while.


Items replaced:
  • cap kit
  • flyback
  • HOT
  • B+ Pot
  • B+ filter cap
  • IC601 voltage regulator (x2 -new one and one off another board has been tried.)
  • Q901 transistor (x2 -new one and one off another board has been tried.)
  • IC401

The area of the board that has most of this stuff has been reflowed. Diodes D601-604 check out, but I could still replace them all from the ones off of another board. H-Hold pot has been checked and tests ok.

Symptoms:
  • No picture
  • You can hear the flyback come on
  • you can feel static near the tube
  • There is a "pop" when the tube is discharged
  • TP91 reads 130+ volts
  • AC at the transformer reads 108v
  • adjusting B+ pot does nothing
  • adjust H-Hold does nothing to the B+ value
  • Pin 9 of IC401 reads 0.6v

Based on the troubleshooting guide it says to check the power reg., hold-down, and high voltage circuits.

Questions:

Have I addressed all of the things in the trouble shooting guide? What are the hold down and high voltage circuits?

What else should I check?
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