Category: Uncategorized

Case # 342553. Mcintosh 754 amplifier. Missing left channel. 09/27/2022
After troubleshooting found protection relay not working properly.
Relay replacement solved the problem.

Repair case # 125432. Pioneer SA-9500II amplifier – no sound, keeps blowing main fuse.
4 Output transistors and main fuse replacement solved the issue.
Instead original transistors we installed MJE15032G / MJE15033G Transistors NPN/ PNP. Works even better then originals.( same terminal design, same configuration) . Main fuse- 4-6 Amp.
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Case #543645/ 09.12.2022 Luxman L-100 amplifier. Low sound from both channels.
Switch MODE/LEFT/RIGHT replacement solved the problem.

Case #456718. Technics SU-7600 amplifier repair. No sound.
06.11.2022. No sound on both channels.
Pilot light is ON.
Voltage -35 volt and +35 volt from power supply are present. All output transistors are ok.
Relay control transistor TR354 ( 2sc828a) replacement solved the problem.

Case #356465. Sansui C-77 preamplifier repair.

Different output signal level in left and right channel . Unbalanced output signal .
Repair.
Changing double front pot 100k ohm ” volume” solved the problem.
Cleaning did not helped.
One of them for some reason changed value to 60K ohm.

Case from 07/06/2022.
Changing power supply filter capacitor 3300 uf solved the problem.

06.11.2022. No sound on both channels.
Pilot light is ON.
Voltage -35 volt and +35 volt from power supply are present. All output transistors are ok.
Relay control transistor TR354 ( 2sc828a) replacement solved the problem.