So I have a 20m2u I picked up recently.
It was stuck in protection mode with the red fault/tally light on and no high voltage to the tube.
Power board was outputting correct voltages.
A hand full of capacitors were reading high or borderline high esr readings so went ahead and recapped the entire deflection side of the board with 105c temp rated nichicon capacitors.
The pvm came back to life but the front panel board was dead and the tube was discharging a loud arc on startup.
Replaced the front panel board and soldered in a custom ground lead directly to the tube grounding fingers that contact the aquadag. No more arcing and the front panel worked so could now access the menu and select input sources.
I fired up 240p test suite to callibrate the geometry and image.... Had it looking great!
Started playing a game and after about 30 minutes the lower portion of the image started to stretch horizontaly and then after a few minutes the image started to bounce vertically , then after another minute or so the vertical bouncing turned into a full vertical rolling like I lost vertical sync. Vertical hold adjustment would not get rid of the rolling.
https://youtube.com/shorts/qzyXlMsnjnw?feature=shareI double and triple checked all the caps I replaced, ended up replacing the sync seperator IC chip..... Same vertical rolling.
Swapped in a different power board.... Same issue.
Happens with composite, component, and rgb inputs.
The menu itself jumps around and is unstable now.
Couldnt remember if I tried swapping the rear signal input board so tonight I tried that and noticed the vertical rolling had slowed down. I then tried V hold adjustment and was actually able to stop the rolling this time but the raster still jumps and shakes vertically.
It seems like a bad cap but I recapped the whole deflection side of the board.
Im not very experienced in troubleshooting live electronics and still need to get a scope but ive recapped a dozen or so crt's and consoles without lifting a pad so pretty possitive its not my cap work thats the issue.
I guess its possible I got a bad capacitor from the factory.
I noticed one of the V output transistors was way hotter than the others. The others were reading 25-30c on a cheap temp gun and that one V out transistor was reading around 55c. Ive never had a horizontal or vertical transistor go bad in a crt before so not sure if they will always just fail or if they can go bad causing issues like im having?
Im now planning to replace the vertical out transistors and check caps esr while the board is out.
I know this shotgunning approach is not the best way to go but Im still learning about doing live testing and yet to get a scope. Trying to save for a 50mHz rigol.
Just wondered if anyone had any similar issues or if anyone had guidance, opinions or suggestions?
Any thoughts are appreciated!
Heres videos of the saga if anyone cared to watch lol
https://youtu.be/cUFdCbEcRZQhttps://youtu.be/0EEp3wBwiochttps://youtube.com/shorts/E0V1uV9gBVE?feature=share