Pioneer SX-1980 Stereo Receiver Fully Restored

For sale we have a fully restored Pioneer SX-1980 Flagship receiver. The unit was overhauled by Ben at Novalux Stereophonic in 2023. The complete report will be included with the purchase. Further, Ben used this unit to do a restoration video which you can find on his youtube channel. Search for "Pioneer SX-1980 Full Electronic Restoration at the Bench" on his Novalux Stereophonic channel, or go to the following link: https://www.youtube.com/watch?v=cFAW2fyFV2Q

The unit is in perfect working order, with all the necessary fixes and mods done to address known issues with the receiver. 

Physically the unit is in very good condition. There are some nicks, scratches on the faceplate and body, and while the unit shows some wear, it still presents itself very well. As mentioned, Ben did the work in 2023, and only now am I ready to sell it. I have enjoyed having it, as it was a piece that I had always coveted. Please see the many pictures of the unit in the listing for further details.  

Report of Restoration: (The printed report from Novalux Stereophonic will be included in the sale)

SX-1980 Restoration Report - S/N: XK3602551S
September 2023 Novalux Restoration
Parts Note: All parts have been sourced through established vendors. Parts used in this
restoration included capacitors from Nichicon (UPW, UES, UKL), Panasonic (FC, FM), WIMA, United Chemicon, and Kemet.

All trimmers are Bourns.

Both relays - Omron.

Resistors when replaced are replaced with the same type with equal or improved tolerance.

Initial Evaluation:
Unit arrived in unknown/untested condition.
● -80V regulated supply dead, showing +3V.
● Power supply shows signs of thermal stress
Restoration:
● Power Supply / Protection
● Main filter capacitors tested for value, ESR, and leakage
■ All four capacitors passed all testing and will remain in unit
● Relays removed and cleaned. Soft start relay is too pitted to remain in service.
■ Both relays have been replaced. Soft start converted from 48V to 24V and
supply voltage adjusted accordingly.
● All electrolytic capacitors replaced
● All transistors replaced
● Additional heat sinking added to 13.5V and 8/5V regulator transistors. Alternate
dropping resistor added to 13.5V supply to reduce thermal stress
● +/- 80V Pass transistors relocated to output heat sinks

● 2SK34 JFET CCS Removed and replaced with discrete 2mA CCS boards
● All Zener diodes replaced
● 35V Zener service bulletin applied (17V + 16V Series Zeners)
● All power supply voltages checked and verified for proper operation
● Driver Cards
● Replaced all electrolytic caps
● Replaced current detect transistor and .22uF tantalum cap
● Replaced bias and DC offset trimmers
● Replaced driver transistors (One board did not have original drivers installed)
● Replaced one resistor and two diodes so that both cards matched
● Tested differential input packages for HFE Match - PASS Original devices left in
place
● Polished pin connectors
● Misc Front End Boards
● Cleaned all push button controls
● Replaced misc. electrolytic and tantalum caps, and trouble maker transistors on
peripheral boards
● Flat Amp
● Removed balance and volume controls and cleaned
● Replaced all electrolytic and tantalum caps
● Replaced known trouble make transistors
● Cleaned switches
● Tone Amp
● Replaced all electrolytic and tantalum caps
● 2.2uF caps replaced with stacked film
● Replaced known trouble maker transistors
● Cleaned rotary carbon tone controls
● Cleaned switches
● Replaced damaged 20KHz treble control with equivalent unit from Pioneer
SX-1250
● Phono Stage
● Replaced all electrolytic and tantalum caps
● Back to back 22uF tantalums replaced with 10uF BP Nichicon Muse
● Known trouble maker transistors replaced
● Tuner
● Replaced all electrolytic and tantalum caps
● Aligned AM (Sencore SG80)
● Aligned FM (Sencore SG80)

● Aligned APC Circuit
● Misc.
● DC Offset set to 0mV +/- 1mV
● Bias set to 30mV on both driver cards
■ Checked for temperature stability on long term testing
● Calibrated meters
Bench Test Results: (Panasonic VP-7725B)
● THD+N @ 1W, and 135W Output into 8 ohms. Aux input
○ 1KHz 135W Aux Input, Volume Control Middle Range .0076% / .0062% THD+N
○ 20KHz 135W Aux Input, Volume Control Middle Range .0224% / .0133% THD+N
○ 20Hz 135W Aux Input, Volume Control Middle Range .0151% / .0089% THD+N
○ 1KHz 1W Aux Input, Volume Control Middle Range .0473% / .0459% THD+N
○ 20KHz 1W Aux Input, Volume Control Middle Range .0469% / .0429% THD+N
○ 20Hz 1W Aux Input, Volume Control Middle Range .0504% / .0493% THD+N
● Clipping Approx 288W into 8 Ohms, both channels driven
● Phono RIAA Tracking - PASS
Listening Tests:
● (3) 10 Hour + continuous listening tests on FM - PASS
● Phono 1 Tested w/ MM Cart
● Phono 2 Tested w/ MM Cart
● AUX and Tape Inputs Tested
● All front panel controls checked for residual noise & proper function
● Speaker A/B/C Tested
● Headphone Output Tested
● AM Tested
● Listening Test PASS
Misc. Cosmetic Notes:
● Faceplate and knobs cleaned and polished
● Dial face cleaned
● Heat sink paint touched up
● Rear panel connectors polished

Specifications:

Tuning range: FM, MW

Power output: 270 watts per channel into 8Ω (stereo)

Frequency response: 5Hz to 80kHz

Total harmonic distortion: 0.03%

Damping factor: 40

Input sensitivity: 7.5mV (mic), 2.5mV (MM), 150mV (line)

Signal to noise ratio: 87dB (MM), 100dB (line)

Output: 150mV (line), 2V (Pre out)

Semiconductors: 12 x FET, 11 x IC, 130 x transistors, 84 x diodes

Dimensions: 560 x 211 x 497mm

Weight: 35.4kg

Accessories: FM T-type antenna

Year: 1978