Electronics Receiver shuts right off

i am new here but i have a question

i have a yamaha receiver(RX-V795) and as soon as i power it up after about 2 seconds it shuts off with a click
i looked over it someone and i could see nothing majorly wrong with it, but im not expert
i have no speakers or anything plugged into it

any help is greatly appreciated thanks

 

it is bad for a amp to not have any speakers plugged in, try plugging some in, it might be a protection system.

 

alright i hooked up some speakers with no luck
while it is on (for the 2 seconds or so) i can change the settings on it(anything on the "screen" of it (phono for example))
hope that helps in fixing the problem

thanks again

 

does it show "protection" or "overload" or something in the display before it turns of?

look for small cords that are shorting the outputs. and disconnect all the inputs.

is it still under warranty?

 

nope nothing on the display that shows an actual warning

as for the cords i assume you mean bits of wire left in the jacks and i didnt see any
with all the inputs unplugged still stops working after 2 seconds

as for the warranty i got this from one of my parents rental cabins
so i am sure the warrany is gone on it

 

Sounds like one of the output sections is shorted. Maybe both channels have shorted. The reason you get power for a few seconds is that there is a speaker delay relay that operates after a few seconds to connect the speakers once the power supply has had a chance to settle. I would check with a meter to see if there is a short on either speaker output jack. Something is overloading the final output stage, between the relay and the speaker connections. At least with most Yamaha amps they use descrete power transistors, so if it is a shorted output transistor, you can usually get a replacement without too much hassle.

 

well i tired testing with a meter
there is a set of 8 of them that act strange from what i think 4 black 4 red
the 4 black work with the meter if i touch any 2 of them
but none of the red work
but shouldnt i be touching 1 red and 1 black with the meter?

thanks

 

_____ All testing is done with the power cord NOT PLUGGED IN !!!!! _______


OK, now you know that there are no shorts on the speaker jacks themselves ( small fragments of wire that fell inside, etc ), you can test internally. The black connectors are all common, so they should show continuity from one to another, the red-to-black test should show open as it did.

First have a look for any open fuses in the amp... lets get the easy stuff out of the way first ! If you have a burnt fuse, do the rest of the checks anyways, something killed the fuse, and there is no point blowing another fuse, so confirm the rest is OK before replacing a fuse. BTW don't put a bigger fuse in, or short it out, you will only make things worse.

Inside the amp you should be able to find a small circuit board where the wires from the speaker terminals connect to. This board will have a small relay on it. Often in Yamaha amps, this board is located near the headphone jack, or the A-B switches for the speakers. Check on this board for wires coming from the amplifier, not the ones going to the speaker jacks.

Check these wires for continuity from one to another. These wires are usually grouped together, and are marked. E is ground, L is Left, R is Right. Check from E ( ground ) to R, and from E to L. All should be open, no shorts.

If you dont find any shorts there, you will have to then check the output transistors. They are mounted on the big heatsink in the middle of the amp. Each transistor has 3 pins, check for shorts between any of the three pins on these large transistors. The transistors are in pairs, often a black one and a green one, easy to spot them, the 4 big ones attached to the heatsink.

Check each transistor individually, if you find a short between any of the 3 pins, the transistor is likely bad.

 

well im slowly taking it all apart and testing them
thanks for the tips
ill post more when i have something