Philips PM-2811 PSU

PHilips/Fluke PM2811

This nice powersupply is capable of delivering 30V and 10A (not at the same time, max 60W) it is programmable over IEEE, and the keyboard. It has memories to save Voltage and current settings. It has CC and CV mode, Over Voltage Protection, over current protection, temperature protection and stepmode. You can program 99 steps and a steptime and the power supply can make sweeps like this.  This PSU can do almost everything you can think of.

To bad it was not working and even more bad the service manual has not all the schematics. The digital part is well documented but the analog part is only “factory repairable”  Everything digital worked but no output. The oscillator was running at 50Hz and 300Vtt. Not good. While probing my probe slipped and caused a short. After that no oscillation. I removed al transistors and fets to test them but all were OK. After putting them back in place the oscillator ran again and this time at 20KHz and that could be good.

I traced the fault to the piggyback board om the powersupply primary. There was a smd transistor that had a unsoldered tab. After resoldering all worked well.

It is very stable and you can even calibrate it. I have done a quick callibration and you see the DMM reading in the yellow box under the meter.

Problems to solve, powerswitch to the front, backlit from LCD works not always, the fan is making to much noise. Sounds like barings. I will place a more silent one instead of this  screamer.

I made some pictures of the undocumented boards.

Power controller board, no schematic in the manual

Mains supply also not in the manual

output smps, no output after the transformer


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