Placid Stability

[steveww]

I have a Placid BP that works fine on the +rail be the - rail starts at 15V then looses 0.1V every couple of seconds finally bottoming out at around 9V.

From then on tweaking the adjustment pot makes no difference.

Any idea why?

 

[steveww]

Something had definitely died as the voltage across VR3 varies with its ohm value. AFAIK this should match Vref at around 4V.

May be a transistor or one channel of the opamp has died.

Any ideas how to test for which?

 

[Russ White]

Usually this is a transposed component. Look for transistors that may be swapped.

Also are the LED lighting correctly?

Continue this on the support forum with pictures if possible. Thanks.

 

[Bassivus]

I have a Placid BP that works fine on the +rail be the - rail starts at 15V then looses 0.1V every couple of seconds finally bottoming out at around 9V.

From then on tweaking the adjustment pot makes no difference.

Any idea why?

I have had very similar thing with mine...

I just tapped on the trimpot few times with my index finger and ever since all is fine 😀