John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

Ok. So. I've got a 13" 20 EZ out of my Donkey Kong 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?