717 with sudden issues help

Got a nice 717 and it's played well until recent. Suddenly after powering on the protection circuit seems to function as it should but the left channel is gone. If I put lets say DSOTM on and get the volume up to 11 or so I get a pop crackle pop then the channel abruptly comes on?? It works for a day or so then it starts all over again Are these amps known for this?

Thoughts:scratch2::thmbsp::thmbsp:

Great find

Hi there, u cld try to deoxit those switches/knobs around.

Mainly there a separate switch for the preamp/poweramp at the back of yr console. Those r probably the cause of yr dropout channel.

Wk all out wif deoxit n revert

The AU-717 is known for one big problem - corrosive glue on the power supply board and amp boards. Component corrosion on one of the boards can (maybe will) cause one or both channels to drop out. As wtppony pointed out, dirty switches can cause that problem, too. The separated/connected switch on the back is prone to get dirty.

As wtppony suggested, clean the switches, especially that separated/connected switch, volume control (a booger to clean), balance, base, and treble switches. My AU-717 took two or three cleanings to get everything to work. Cleaning switches may cure the problem, may not.

While you have the amp open to clean switches, take a look at the power supply and amp boards. If you see resistors or diodes with green leads, you have corrosion and the amp will fail sooner or later (probably sooner).

The AU-717 is a great amp, but if the corrosive glue hasn't been cleaned up and corroded components replaced, it may not last very long. Mine didn't. Search through AudioKarma. There is a wealth of information about cleaning up these amps and which components are weak links and need to be replaced.

Bro qpagoda, yes quite extensive feedback u quoted :yes:

The volume control consist of 4 wafer level, for this u gt to dismantle the faceplate,knobs n the preamp board to access to it.

There r a few ways to clean it. Generally the step atteunator volume is being held by 2 silver long screws tat secure the unit assembly. Unscrew those n u find yr wafer housing tends to wobble. At the back of the wafer housing do hav a sticker to it. Carefully pull it out, n u see a kind of C-clips holding onto the groove of the volume shaft. Release the C-clips(often spoilt by then) n remove the housing n cabon wafer in order, clean those wipers, carbon boards wif cotton bud soak wif D5, dry it n then apply faberlube(thinly) to those carbon based board n fix back the assembly.

wtppony said:

Hi there, u cld try to deoxit those switches/knobs around.

Mainly there a separate switch for the preamp/poweramp at the back of yr console. Those r probably the cause of yr dropout channel.

Wk all out wif deoxit n revert

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I had already cleaned all the switches or so I thought. Took your advice and cleaned thoroughly the separate switch. Happy to report thr au 717 is working without any issues. Still going to have it gone over and have all the mentioned issues these have

Axcel said:

I had already cleaned all the switches or so I thought. Took your advice and cleaned thoroughly the separate switch. Happy to report thr au 717 is working without any issues. Still going to have it gone over and have all the mentioned issues these have

Click to expand...

I presume u took out the switch to clean its rail? Tat a vry gd step u made n remember to lube it wif progold b4 the assembly.

The fuse resistor in the driver(1/4w,150ohm), pre n phono board(1/4w,82ohm)shd be address to.

Nasty glue tat holds those big caps like 470uf shd be cleaned as well, aft tat u cld go though a full recap wif a schmetic diagram cos caps tends to dry out over this long periods of usage thus loses their charge eventually.

Relay contacts tend to hav a darkened surface(pit) so u can either change or service them.

Remember to take lots of pictures, jotting notes, drawing diagrams or marking various pt wif colour marker to assist u in the assembly stages.

it sounds like the issue is with the speaker relay .try tapping it gently with a screwdriver handle