I have a technics su-v660 integrated amplifier.the voltage selector light comes on but the current drive light is intermittent .when the red drive light is on it works PERFECTLY but only for 5 minutes then it gives an unbearably high feedback type squeal and off goes the red light, but it still has power as the amber light keeps working,just no sound unti current drive light decides to work again which is usually next day. there is no smell or heat problem.the current drive light goes out even with no speakers connected.its a really old amp but i would love to save it.

Use the preamp out port.

You'd have to at least tell us which transistor you need info on in order for us to tell you the bias voltage. There are several, and all are different.

Greetings
Is there any indicator on or its all off?
anyway i will assume that there is none
1.check power fuse if blown.
2.check power transformer if there is any output voltage
3.check internal fuses
more information will give a better idea.
try these steps and hope this helps.

It sounds like the switch might be broken. It might need to be replaced.

Check the relay control transistors. Check the voltage at the collector and base of this transistor. Download the service manual to your device to get more details.

Check for dry solder joints especially on the main power output transistor.
A blown power transistor will stop the 'Current Drive' from engaging so if the problem you have is intermittent then it is most likely dry solder joints.

Hope this helps.

Your amplifier is turned on and all the indicator lights work and you made it sure that all the cables, and cords are attached to where they are supposed to be connected and yet you don't get any sound coming out when you play a music. Amplifiers have selector knobs for you to set where your source is coming from. Selector knobs can be set to TUNER, DVD, CD, and AUX. The scenario might be like this: your source is coming from a movie being played on your DVD player connected to your amplifier but your knob selector is set to AUX. Try playing a music selection from your CD player attached to your amplifier and set the selector knob to CD. If still there is no sound coming out you need to have it checked by a qualified technician.

Unplug the power, open the case and try to locate some electrolytic capasitors is series with the audio at the channel with the problem. One of them must be blown.

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Thanks and regards
Please kindly rate this solution
Stelios
direct FixYa link: http://www.fixya.com/users/technical114

Hi max

I have done a followup with Technics Parts agents in the US, they will get back to me and then me to you shortly :) A vote as FixYa would help improve my ratings. Thanks

Graeme

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