Hi rynoshark - my experiences with Linn power supplies always seems to trace any problems back to the electrolytic capacitors. On many occasions the caps have measured ok but replacing them brings the PS back to life?
Intermittent faults such as yours are the most problematic to resolve as it may be as simple as a dry solder connection?
The AV5125 is a fantastic amp and I owned one several years ago although I had it upgraded to a Dynamik PS.
Hi Donald, I recently bought an AV5125 which operated fine for about an hour then popped! The blue light doesn't illuminate, so I'm guessing the SMPS is bust. Did you ever find a replacement power supply for your AV5125?
Hi Nyatt. Are they a direct replacement? If they are I'd definitely be interested. How much do you want for one? I'm in the UK....
The ones I have have a +/-46V output, and I think that is compatible for the 5125, but I am not positive. You should probably check first.
If it's of help to anyone, I have just opened up my AV5125 to measure the SMPS output voltage. It's a pre-Dynamik PCAS254/L4R, just like the one in the original post. It is +-30 V on pins 1, 2 and 11, 12 out of the psu. The demand voltage on pin 4 i 3,3V and of course used for the signal sensing standby feature. I verified the voltage to be the same going into the inductor 029.
The reason I checked is I because recently got hold of a Select Dynamik psu cartridge that was switched out for the new Utopic psu. I was hoping to be able to hotrod it somehow into my amp, but it has a much higher voltage at +-45 V. It also has a +25 V and a +12 V rail as it is used for both pre- and power-amp functions in the modular Selekt platform. I have to do some more research to see if i can use it for something else or regulate it down. I doubt that the AV5125 circuit could handle that much overvoltage, even though the output chips definitely can.
The reason I checked is I because recently got hold of a Select Dynamik psu cartridge that was switched out for the new Utopic psu. I was hoping to be able to hotrod it somehow into my amp, but it has a much higher voltage at +-45 V. It also has a +25 V and a +12 V rail as it is used for both pre- and power-amp functions in the modular Selekt platform. I have to do some more research to see if i can use it for something else or regulate it down. I doubt that the AV5125 circuit could handle that much overvoltage, even though the output chips definitely can.
I was thinking... if i were to replace the whole SMPS with a 30/50V power supply, would it even turn on, if I dont commenti the DEMAND pin to anything? Trying to get a less time consuming alternative to replacing a blown resistor and trace the damage origin...
I didn't trace where the demand voltage was generated, but I will do next time. There is no remote for the 5125 so I guess the VCC and VDD are always on. But there is a signal sensing circuit so the output transistors are not always on. I suspect the demand voltage somehow interact with this. I'll report back next time I've had a look at this unit.
This is very old thread and I don't know if the OP still look for power supply. I have old unused LINN DYNAMIK power supply brand new in a box. I just measured the output voltage +/- 30 (more precisely, 29.6 V with my DMM). I'm about to build an amplifier with this power supply, but it doesn't necessarily require LINN brand. So this can go to whom really demand replacement of LINN PS. I then anyway need a good SMPS with 28-30 V thus requires some budget covering shipping, though.
