Yamaha M-35: No Sound

[dav305z]

Picked up a Yamaha M-35 4/2 channel amp at a thrift store for $15. It powers up fine, but sends no sound to the speakers. Any idea why this is? I have no manual for it, so I don't know if something is set wrong (not there are many buttons).

[caesar148]

Since both channels are not working, I can think of several possibilities:

1. Protection circuit problem
2. Blown fuse
3. Burnt out transformer

If you do not have basic electronic skills, it would be best to refer the troubleshooting and repair to a qualified service technician. Fixing such equipment require the right tools like an oscilloscope, audio signal generator and multimeter. If you would like to pursue this further, you can download the service manual from this site. It will cost you though.

http://www.servicemanuals.net/ServiceManual/YAMAHA/M-35/pos1/results.aspx

[bfalls]

These have a level adjustment on the back for each channel. They may be adjusted all the way down.

[trollgirl]

I have one of these, so pay attention.

Power it up - does the light above the switch come on?

Push the button to engage the speakers (wait few seconds after power on).

For that matter, did you pay attention to the speaker hook-up on the back panel? This amp is two OR four channel, and the speaker hook up for each is different. Examine the back panel, it is not too hard to figure out.

The inputs are for two OR four channel also, so make sure your source is connected to the correct inputs.

Note that there is a pot for the left channel(s) and a pot for the right channel(s). Did you crank them? Do have these at zero at power off and power on.

Laz

[dav305z]

I've tried hooking it up and turning the dials every which way, no dice.

The one thing that makes me think somethings really wrong here is that there's no "click" when I power it up. Every other reciever/amp I've ever owned has "clicked" when I turn it on. Is this a sign of a blown transformer?

[Gerard]

Assuming that you have carried out trollgirl's helpful tips, and you are sure that the light above the switch is illuminated, well, I think the reason you did not hear the "click" could be due to output devices not turned on or failed, and the protection circuit did not turn the relay "on" as there is an unsafe operating condition present.

I don't own one of these, so I don't really know what's inside. Since Yamaha is Japanese, your amp could be powered by a "switching mode" type of power supply. In which case you won't see the normal transformer. What you will see is a metal box sort of module, quite similar to the desk top p.c. and you don't want to fool around with these!

Caesar148 gave good advice, if you are not familiar with electronics, have a qualified technician take care of it.