Sjöström Audio DIY forum

Projects => Power supplies => Topic started by: Olivier M. on December 14, 2008, 09:48:55 PM

Title: QSXPS - weird output voltage
Post by: Olivier M. on December 14, 2008, 09:48:55 PM
I get 7.6V out of both output rails of the QSXPS. (with R43 - R49 and P1 are soldered on the picture but R49 has one pin lifted)
Looking back at a preview topic, I checked several voltages and they all look right.

V(IC3)=5V
V(IC1-pin5)=5V

Vout Unstab = 29V

I have attached a picture of the positive side of the board in case there is something obvious that I missed.

Any idea? What other voltages can I check?

Olivier

[attachment deleted by admin]
Title: Re: QSXPS - weird output voltage
Post by: peranders on December 14, 2008, 10:03:16 PM
R29, which value? Red-Red-Red is normally 2k2 instead of 2R2 ohms.

You should not have all resistors fit in the feedback, at least this was not my intention.

Which output voltage do you want?
Title: Re: QSXPS - weird output voltage
Post by: Olivier M. on December 14, 2008, 11:25:26 PM
You have a good eye. This is the faulty value!
I had checked all other values but left this one.
I swapped it with a 2.2 ohm resistor and I now get the desired 15 volts.
Thanks
Title: Re: QSXPS - weird output voltage
Post by: peranders on December 15, 2008, 06:34:44 AM
Good to hear  :-D