Hi all,

I am looking to refurb a mitsubishi DA-P20 and DA-A15DC preamp/amp combo to original condition. The attenuator knob is noisy and being the unit is 30+ years old and lived in a smoking environment, I'm sure it has lost a little of it's golry.

Anyway, I am looking for recommendations for a shop in the Calgary area that is reputable for a refurb and proper test to ensure that the unit is at factory spec output. The unit has great sentimental value to me, so I want to get it looked after right.

Thanks!

HC, I don't have any info about shops in the Calgary area, but on the noisy control, note that rotating it rapidly from min to max a couple dozen times(sound off, of course)may clean it enough.

I've had good experiences with Bestech

Hi,

I've had excellent results using Caig Laboratories Pro-Gold or Deoxit cleaner/deoxidizer spray to clean up noisy attenuators, switches and controls on old gear. The effects seem to last for at least a couple of years before you have to clean them again. Use very little of the spray, just a quick spritz into the control or switch.

Regards,
Alan

Thanks, maybe I'll try to take the case of first and clean up any obvious deposits and see if that helps. I grew up with this behemoth and it was handed down to me from my pa. My first stereo.... not bad. It's a couple years older than me.

and what a powerhouse!! 2 discrete monoblocks at 150wpc. Weighs over 50lbs.

I still have the original hand written receipts and manuals from when he picked them up in 1978. Funny thing is, years later I unknowingly visited the same store (different name) and bought a home theater package. Like father like son, eh!

All sound advice, report back on your results, and good luck.

Here is where I am at so far. I'm going the DIY clean route first to see if that gets any improvements with the noise floor and crackly attenuator. I am focusing on the pre-amp, as I've routed my modern AVR to the power amp inputs and the output is still pretty clean sounding. Maybe i'll change out the caps at a later date.

Once complete I'll let you know how it worked.

I will of course be blowing the unit out with canned compressed air and spraying the pots and switches with Pro Gold if I can get some.

I Found a really informative vid on youtube about how to do this, so enjoy.

http://www.youtube.com/watch?v=njwi-GwJBzc&NR=1&feature=endscreen

Anyway, here is the unit assembled:



Here is the unit divorced:



Here is the preamp undressed:



Closeups of pots and push button switches:



Closeups of input Selector switch and volume attenuator:

I wish I could unsee some of that.

The DIY refurb complete for now and the results are great. The scratchyness on all dials and master volume are gone.

Noise floor is gone. Sound is clean and open with good separation. It used to sound like blare soup in comparrison.

Great project that is relatively inexpensive if you have old gear. Made a big difference for me. Fun too.

I used Deoxit D5 first then Deoxit Gold after. Each with 24hr inbetween applications to let dry out before powering on. I used a lot I guess. Some boards were soaked by the time I was done.... but that probably did good things anyway. Looks like new inside and out. Highly recommended.

Nice work. Glad to hear it sounds like new again.
I've been putting off cleaning up an old Technics receiver I've been meaning to clean up mostly for just radio. Maybe this will inspire me.