Power Designs 2020B

[v1t0r]

Recently I got a Power Designs 2020B, converted to 230v by changing the connections on the transformer, but when I try to calibrate it to zero volts it does not falls below 110mV. Any idea on what could be wrong.
Thanks
Vitor

[saturation]

A common problem is dirty and less likely, faulty, fine adjustment potentiometer, this is the 10 turn pot underneath the main dials.   Cleaning it can't hurt and see what happens.  Use a very high quality metrology grade contact cleaner, in the USA we use Dexoit.

P.S.  To help the diagnosis turn the pot clock and counterclockwise, the output voltage should rise and fall in step.  If it jumps around or doesn't rise or fall in step, its more likely the cause.