My beautiful SX-1980

Wednesday, July 27, 2011

Pioneer SX-727 pot repair

Got a SX-727 to repair, works perfectly, but the volume pot has a broken shaft and the balance pot was damaged by someone yanking on it. Here are some photos of the damage:

It's now repaired and working great! One of the cleanest receivers I have ever seen, the way you see it in the photos is the way I got it.







Thursday, July 7, 2011

Pioneer SX-1010 repair and restoration

This is a 1010 I got off of eBay, I'm going to be restoring it back to it's former glory. Problems with it are a cut power cord and when a temporary cord was put on, it powered up, but no sound was output. So far, I have found at least three things wrong, plus somebody was in here before me and did a awful job, so I'm going to have to reverse that along with the problems, no doubt caused by the incompetent tech.

The unpacking process, it is nicely packed, I am very pleased with the job.




Here she is! Quite dirty, though it's hard to tell from the photo. Also the glass is cracked, I hope I can find a replacement.


Some shots of the inside.



Power cord repair, it turned out very nicely.



The monkeyed protection board, cheap Chinese caps and a transistor that does not belong were put in.


Broken trace repair on the power supply. Man!


Found a crack running the entire width of the power supply, the white line indicates where it how it runs where the camera couldn't see.




I have repaired the last broken trace and upon power up, the relay clicked! Yay! Right channel is good, DC-offset and idle current are perfect, however the left channel, not so good, all of the outputs were replaced, two of them with counterfeit Sankens along with a poorly done STV diode mod. The STV was moved from the driver heatsink where it's supposed to be to the output's heatsink, and the STV was screwed down so tight that the the top right half came apart the moment I loosened the screw. Ugh.

Edit: The STV diode mod was actually done by the factory, I just found out that they changed it mid-production because being on the driver heatsink was allowing too much variance in the bias and causing the outputs to become very hot. That is the reason for the different board numbers mentioned below, The "D" board is the later board when they switched to diode to the main heatsink instead of the driver heatsink. That STV-3 on the board was also factory.


Back of the board, arrows indicate where the black jumper wires you see on the front connect.


Made another discovery, the power amp boards are totally different, the left channel is a AWH-032-D, the right is AWH-032-0. The left channel has several diodes that have been replaced, one with a STV-3. Huh?

Edit: Never mind, that STV-3 is suppose to be there, see above.


And now, presenting the recapped and cleaned up, SX-1010! I still have not been able to find replacement glass or even better, a faceplate, but I will. The current faceplate is pretty dinged up, it's definitely seen better days. Almost every transistor was replaced on the power amp boards, all 8 outputs were changed to ON-Semi MJ21193G and MJ21194G outputs. All new transistors in the preamp as well, plus a full recap and the main filter caps were bypassed with Panasonic ECQ 2.2uF film caps.






More photos will follow, once I get done listening to it and drooling over how it sounds. :-D

More photos! Additional photos to follow, I have the case off it right now as I'm restoring it.