Agilent 6633B Repair.

[vaualbus]

So I was luck and buy on ebay for 35$ (originnaly 50) a not working Agilent 6633b power supply.
When it arrive I found that a resistor(R300) was missing and there was sign of burning. After changing the resistor I was not having high hopes of having a working psu.
Anyway I power it on and apparently it works!.
But there is a thing that could be wrong.
The supply have 3 output pins. + - and gnd.
So I suppose that if I set 20v i would get 20 between +/- and if I take the ground as reference I should get +10v  and -10v.
So I try it and it not working as I excpeted. I can get -10 between gnd and the - terminal but I get nothing between gnd and + terminal.
It is normal and the ground is just the chassy ground or the supply have some problem I have to fix?
Thanks, Alberto Vaudagna

[Andy Watson]

The supply have 3 output pins. + - and gnd.

There is only one output - which should measure 20V between + and -. The ground is there for convenience and the power supply output will be floating with respect to the ground.

[vaualbus]

a ok than it is working. Thanks.
But anyways that resistor is getting very hot. it is a W resistor but it get very hot. (don't have a term camera but it burn if I touch it).
I don't undestand what can cuase the resistor to be hot..

[Kleinstein]

R300 is just for discharging the filter caps. So it's normal it dissipates quite some power - the supply would even work without it. It's more a safety thing, so it the caps will discharge for a possible repair / service. If it's too hot, one might consider a larger form factor or a slightly higher value.

[vaualbus]

A ok  thanks for the clarification