Technics SA-R477 This has been a wonderful receiver. I've had it for about 20 yrs. and just recently I went to turn the unit on and the power and volume were working fine and a few minutes after being on, the volume stopped.

SOURCE: technics SA-DX950

when turn on receiver , after few seconds got message
F70. when wants to do any operation with receiver got message SWITCH POWER OFF

SOURCE: I have a Technics SA-AX610 receiver that says overload .

From the manual pg 27....... "The protection circuitry has functioned because the positive and negative speaker connection wires are "shorted," speaker systems with an impedance less than the indicated rated impedance of this unit are used or under severe use, such as loud volume, excessive power and in an excessively hot environment."

SOURCE: Technics SA-DX950 intermitently sounds blown out

There are poor solder connections at the output amp pacs and the voltage regulators. Once these are resoldered the problem should go away. If you can solder, resolder any connections that appear grainy or have rings. If you can not, this should be effectively a labor only repair for any shop that works on audio gear.

Dan

SOURCE: Technics sa 400 Receiver

Checked fuses then sprayed contact cleaner on the fuses and the fuse holders. The speakers began to work correctly.

SOURCE: Max. wattage for speakers w/ Technics Receiver SA-GX100?

I too have a Technics SA-GX100 and it's rated at 2 x 40W @ 8 Ohms. I have the Technics SB-2840 floor model speakers hooked to it, which are rated at 200W Music Input - 8 ohms. It sounds very nice just to be a 40W receiver.