The NEW Build Your Own Arcade Controls

Main => Monitor/Video Forum => Topic started by: the_77x42 on May 05, 2018, 12:48:56 pm

Title: 25K7191 Shutdown Pot Adjustment
Post by: the_77x42 on May 05, 2018, 12:48:56 pm

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!

Title: Re: 25K7191 Shutdown Pot Adjustment
Post by: buttersoft on May 07, 2018, 12:14:18 am

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

Title: Re: 25K7191 Shutdown Pot Adjustment
Post by: the_77x42 on May 07, 2018, 08:07:23 pm

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:

Quote

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.

Title: Re: 25K7191 Shutdown Pot Adjustment
Post by: buttersoft on May 07, 2018, 09:54:37 pm

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

Quote from: the_77x42 on May 07, 2018, 08:07:23 pm

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:

Quote

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.

Title: Re: 25K7191 Shutdown Pot Adjustment
Post by: the_77x42 on May 08, 2018, 05:20:47 am

Quote from: buttersoft on May 07, 2018, 09:54:37 pm

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.

Title: Re: 25K7191 Shutdown Pot Adjustment
Post by: buttersoft on May 08, 2018, 07:45:44 pm

Righto, i was merely curious. Thank you :)

Title: Re: 25K7191 Shutdown Pot Adjustment
Post by: security0001 on January 09, 2022, 06:27:26 pm

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/

Title: Re: 25K7191 Shutdown Pot Adjustment
Post by: buttersoft on January 10, 2022, 06:52:43 pm

Appreciate the info!