I purchased this Pioneer SX-535 from a local shop. With the exception of the broken face plate in the tuner window, the unit is in great shape inside and out. All original and in working order. So, I decided that this would be a great unit to rebuild.
Power Supply: I replaced the main filter caps with new Nichicon LKG Gold Audio Grade caps at 6800uF @ 63V. A bit higher than the original 4700uF caps but that’s all I could get and no harm done. I replaced the bleeder resistors with new 5 watt resistors. All electrolytic caps on the power supply board (AWR-065) were replaced with new long-life Nichicons or Panasonics, depending on what was available from Mouser. All diodes and resistors were checked and found in good working order. I did add a small heat sink to the 2SD234, mostly because I had one around and, why not?
Control Board: I replaced all electrolytic caps with new, long-life Nichicons or Panasonics. I also replaced all the old Sanyo caps, which are known to fail miserably, with new Cornell Dubilier, DME Film caps. All pots and switches were cleaned with DeoxIT.
Tuner: All 6 old Sanyo caps were replaced with new Cornell Dubilier, DME Film caps.
Phono Preamp: All electrolytic caps were replaced with long-life Nichicons or Panasonics. I also replaced all 4 original 2SC1312 transistors with better sounding Fairchild KSC1845FTA transistors. Resistors were checked and found to be fine.
Power Amp: All electrolytic caps were replaced with long-life Nichicons or Panasonics. The troublesome original 2SA726 transistors were replaced with new Fairchild KSA992FBU transistors. Resistors were checked and found to be fine. I also replaced the original bias pots with new Bournes 362-line pots and was able to set the bias at exactly 15mV for both channels.
Front Panel: I decided to replace all the original incandescent lights with new LED’s. I used a bridge rectifier and dropping resistor to power the whole display properly. I added 10 blue LEDs to the tuner dial, an orange LED for the tuning indicator, and white LEDs behind both tuner meters. I then replaced the stereo indicator with a red LED and appropriate dropping resistor to set the brightness level properly.
And finally, I gave the whole thing a good cleaning, inside and out. Everything works perfectly and sounds absolutely amazing! This unit should deliver great music for another 40 years.
If you have a receiver like this that you feel is worth keeping, you should consider having Seven HiFi perform a full rebuild on it. Not only will this greatly increase the reliability and lifespan of your unit, but it will also regain it’s original, wonderful sound! Contact us today!