Voltaic Vintage Repair & Restore

Voltaic Vintage Repair & Restore Vintage Audio and Electronic device repair services Electronic repair service and restoration specializing in Vintage Audio Gear from the 60s, 70s, and 80s.

Under $100.00 is repaired automatically. If it's over $100.00 or whatever amount higher than what you set, I would contact you for approval. If at that point you decide not to repair, then it's $40.00 to diagnose.

Finished a rebuild of a Yamaha B-2 amplifier.
08/10/2026

Finished a rebuild of a Yamaha B-2 amplifier.

Update on the Kenwood KR-9050. Long term testing showed the DC offset on the left channel drifts 100mV. Q1 and Q2 are ...
08/10/2026

Update on the Kenwood KR-9050.

Long term testing showed the DC offset on the left channel drifts 100mV. Q1 and Q2 are JFET dual package 2SK150A BL rank transistors. Which is the source of the DC drift.

I found a dual package replacement with a LSK389 B rank. Using perf board I matched the footprint of the 2SK150.

DC offset is now stable and the unit is ready to go back to the owner.

Long-term testing a Kenwood KR-9050 after full restoration. It looks and sounds great. 200watt per channel power house!
07/30/2026

Long-term testing a Kenwood KR-9050 after full restoration. It looks and sounds great. 200watt per channel power house!

Another fun project in the books. A very nice Pioneer SX-1250 receiver full restoration.
07/17/2026

Another fun project in the books. A very nice Pioneer SX-1250 receiver full restoration.

Finished restoring a really nice Realistic STA-90. Well built unit. Machined aluminum k***s, glass dial face, nice woo...
06/23/2026

Finished restoring a really nice Realistic STA-90. Well built unit. Machined aluminum k***s, glass dial face, nice wood case. Only weakness, the speaker connections. Got that taken care of with new 5-way terminals.

Yamaha CR-2020 ready for cleaning and restoration!
04/16/2026

Yamaha CR-2020 ready for cleaning and restoration!

Becker Europa TR car radio from a 1967 Mercedes back up and running again. Had many open and high ESR capacitors. Repla...
04/02/2026

Becker Europa TR car radio from a 1967 Mercedes back up and running again. Had many open and high ESR capacitors. Replaced all the electrolytics. Cleaned up the dial face and k***s. Added some paint to the dial indicator.

These Heathkit W4-AM amplifiers went to their owner with Dave Gilespie designed EL34 mods. Removed all old circuits, c...
04/01/2026

These Heathkit W4-AM amplifiers went to their owner with Dave Gilespie designed EL34 mods. Removed all old circuits, cleaned and polished the chassis, sanded and painted the OPT and choke, machined new switch and lamp holders. Built a bucking transformer. All new components.

Looking and sounding great!

Had a short between two inner ground planes on a circuit board. 8 Amps did not fuse it open, but it did reveal a warm s...
02/27/2026

Had a short between two inner ground planes on a circuit board. 8 Amps did not fuse it open, but it did reveal a warm spot. Milled down 0.004" to reveal the ground planes and the short!

Pioneer SX-850 Restoration:Findings: Power cord has been spliced. AM bar antenna missing. One bottom cover screw is mis...
02/03/2026

Pioneer SX-850 Restoration:

Findings: Power cord has been spliced. AM bar antenna missing. One bottom cover screw is
missing. Left and right DC offset is unstable
and tripping protection circuit (relay clicking
on/off). Q1-Q4 are bad on output amplifiers. All lamps are working (dial, indicator and stereo). Power supply Q3 & Q5 previously replaced with 2SC484 & RCA SK3020. –19V supply is not working (Q6 and C23 are bad). Q1-Q6 and C7 and C8 of equalizer amplifier are bad. Left auxiliary input is not working. Function switches are intermittant and need to be dis-assembled for cleaning and servicing. All transistor heatsinks need new thermal compound (dried). Relay contacts are intermittant (needs replacing). Main filter caps measure half of rated value. AM and FM need alignment.

REPAIRS: Replaced power cord. Replaced AM bar antenna. Replaced Q1-Q4 on output amplifiers with gain matched KSA992
transistors. Calibrated DC offset and current bias. DC offset is now stable and relay does not click on/off. Replaced Q6 and
C23. –19V supply is now working. Equalizer amp: replaced Q1 & Q2 with gain matched KSA992s, replaced Q3-Q6 with KAC1845,
replaced C7 & C8. Equalizer amp is now working. Removed function switch pcb, dis-assembled each switch, cleaned and
polished and applied G100. Function switches are now working good.

RESTORATION: Washed and dried entire unit. Replaced all electrolytic capacitors with MKS2,FR,FC,UKL. Re-stuffed main filter caps with 15000uf/50V. Power supply replaced Q3,Q7 with KSC2383,Q5 with KSC2690. Protection unit replaced Q7 with KSC2690, added 1N4004 to pins 9 & 10. Replaced all “black leg” transistors (2SC869,2SC1312,2SC1313,2SA725,2SA726) with KSC1845 and KSA992 transistors. Replaced protection relay. Replaced bias and offset pots with Bourns 25 turn. Replaced dial lamps with warm white LED and all function, stereo and speaker with 8V/50mA/4mm lamps. Replaced all heatsinks’ thermal compound. Applied D5/G5 to all switches, D100/G100 to all inputs and outputs, D5/F5 to all control pots. Calibrated bias and offset.
Aligned AM and FM bands. Cleaned and polished front face and k***s. Applied Howards-Restore-A-Finish to wood. Verified all inputs and outputs. Outputs produce 72W into 8ohms at 1Khz (rated at 65W). Ran unit for 8 hours with no problems observed.

Address

Eau Claire, WI

Telephone

+16123619949

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