Pioneer SX-939 Stereo Receiver. FULL REBUILD JAN 2026
Only 1 left in stock
Pioneer SX-939 Stereo AM/FM Receiver.
Fully restored in January 2026. I use ONLY hiqh quality audio grade parts, ordered at Mouser/DigiKey. No corner cutting to save a few bucks.
What was done:
Both filter capacitors have been replaced/upgraded from 10000uF 50V to KEMET 15000uF 63V with the same diameter to keep the original design.
All eight power output transistors were replaced with 100% matching hFE Onsemi MJ21195G/MJ21196G pairs.
Usually restorers skip both steps above to cut costs. I believe this must be done for a full restoration. Filter capacitors and output transistors must be replaced.
New Omron relay was installed to improve reliability.
LED upgrade for dial scale and VA meters.
ALL electrolytic capacitors have been replaced with audio grade Nichicon (UPW, UKL), WIMA and Kemet film caps.
All electrolytic capacitors on the power supply board were replaced with higher-voltage parts to improve reliability.
All known problematic, noisy, or potentially failing parts – transistors, resistors, and diodes – have been replaced with ON Semiconductor and Fairchild components.
Bias and DC offset adjusted to factory specs. New 25-turn Bourns trimpots make the adjustments easy.
A carefully selected audio-path transistor replacement with 100% matching hFE brought us the following perfectly matching results after restoration (see the last photo).
Exterior conditions:
Faceplate. The front side is in very nice condition, but the top of the faceplate has imperfections, not visible from the front view. They are pictured. Knobs are nice looking, but smallest ones have minor misperfections. They are pictured.
Cabinet. The top wood cabinet/cover is almost perfect. Wooden parts were reconditioned with a walnut finish.
I did my best to picture ALL imperfections.
Every restored unit has a full burning day at medium volume in FM mode.
Will be double boxed and fully insured for shipment. Shipping may be expensive – see the last photo to see how your unit will be packed, so local pickup is always welcome!
Cross-listed on ebay.
