25K7191 Shutdown Pot Adjustment

[the_77x42]

I have a K7000 P538. The factory lacquer on the VR8 HV Shutdown pot was all over the place, covering up the entire bottom of two of capacitors I'm replacing as part of a cap kit.  While I was scraping off the lacquer, I moved the HV pot around. I'm replacing the pot as well.

What is the proper way to adjust the HV Shutdown pot on this board?

Thanks!

[buttersoft]

I've never heard of an HV shutdown pot. How does it work, exactly?

[the_77x42]

As the high voltage increase, the shutdown pot limits it from damaging the board if it gets too high. It does this by placing the board into shutdown. I emailed Buffett and this is his response:

set the pot to the center.

difficult method.
turn it up till the monitor shuts off, turn it back a little till the monitor does not cut off for 36 hours continuous.

easy method.
set the pot to it's center and see if the monitor runs for 24 hours continuous.
if it stays on, call it a day.

[buttersoft]

So, it's the B+ adjust...? Or is it keyed directly to the B+ itself?

As the high voltage increase, the shutdown pot limits it from damaging the board if it gets too high. It does this by placing the board into shutdown. I emailed Buffett and this is his response:

set the pot to the center.

difficult method.
turn it up till the monitor shuts off, turn it back a little till the monitor does not cut off for 36 hours continuous.

easy method.
set the pot to it's center and see if the monitor runs for 24 hours continuous.
if it stays on, call it a day.

[the_77x42]

So, it's the B+ adjust...? Or is it keyed directly to the B+ itself?

It's keyed directly to the B+ I assume? It's technically not a B+ adjustment from what I've read.

[buttersoft]

Righto, i was merely curious. Thank you

[security0001]

this information on the shutdown pot is a little archaic so i will make some clarity of how its supposed to be adjusted when replaced.  you measure voltage on the cathode of D12 and adjust the pot to 9.8v is what the factory method is.  this is also listed on our site in the B+ settings tab.

 https://www.arcadepartsandrepair.com/tech-help/monitor-b-settings/

[buttersoft]

Appreciate the info!