Europower PMP1280S-Power Supply

[gp8005]

Hi All,

I am repairing the SPS 1000/02 power supply on the above mentioned Amp. I need to know what the values are for R11 and R12. The markings on the resistors are 310-3 10R 5% W. I have not been able to cross them with anything, and would appreciate anyone's help.

Gilbert

[Enzo]

10R means 10 ohms. In the same way 4k7 means 4.7k ohms or 0R33 means 0.33 ohms. I forget what size they are in wattage, 5,7,??

Those are your soft start resistors. If they are burnt, there is a good possibility the SMPS is further damaged, check the switching transistors and all secondary rectifiers for shorts.

The schematic calls for 22 ohms there, but different revision levels often make small changes like that. If it came with 10 ohm resistors originally, then stick with that.

And remember that SMPS are EXTREMELY dangerous to work on. It rectifies the mnains directly - 340vDC with all the current of the wall outlet. I highly recommkend using an isolation transformer. And note that on the primary side, the circuit "ground" is really the V- rail, or about -170v from earth. Don;t ground your scope probe there, is what I am saying.

The SPS1000 was also used in models like PMP3000, PMP5000, which may be easier to find online. Elektrotanya is a good place to look.

But if you use the search box for THIS forum, and enter PMP1280S, the schematics are posted in at least three places.

[gp8005]

Enzo, Thanks for the input; especially the safety precautions. It has been years since I worked at the component level. It's amazing how much a person forgets. I will follow up with your suggestions. Have a good one.
Gilbert