Onkyo SR705 NEWB Needs Help

[litezoner]

This unit powers on for a moment and then shuts itself down after about 5-10 seconds, where would I look first?

Thank you

[ostripper]

Sounds like a blown output device making dc.

protection circuit
kicks in, saving you from smoke and fire.

With a multimeter look for white ceramic block with 3 pins
sticking out top near heatsink , measure middle pin
of each. Any one that does not read 0 volt before amp
shuts off is the channel blown.

[litezoner]

Thank you, so check the middle pin when I power it up, should be 0 volts with power on? and this would be DC Volts? so ground the black end of the dmm to the chassis? Thank you again

Carl

[steven344]

Check all the transistors on the heatsink for shorts between collector and emmitter,middle pin and right pin also the white resistors can open up.You can also have the driver and bias transistor go bad when the output shorts and take out other transistors and resistors .If all other parts are not check it will blow again .I trick is to put a 100 watt 120volt lamp in series with the amp your working on to prevent damage when you replaced parts.

[steven344]

Check all the transistors on the heatsink for shorts between collector and emmitter,middle pin and right pin also the white resistors can open up.You can also have the driver and bias transistor go bad when the output shorts and take out other transistors and resistors .If all other parts are not check it will blow again .I trick is to put a 100 watt 120volt lamp in series with the amp your working on to prevent damage when you replaced parts.

[steven344]

The txsr605 manual you sent me should help you with the txsr705 your working on ,most brands dont change much between years as long as the are about the same age..Look at the schematic of the ouput section and check outputs ,drivers bias transistor and resistors.

[litezoner]

Well Folks, This seems way beyond my knowledge and expertise area, anybody live near Temecula California that would like to service this unit for me, I will ship if nessasary. What do you suppose would be a ballpark worst case sanario as far as cost to repair? Let me know if anybody local? or is interested?

Carl u4shop@aol.com

[steven344]

Hello,Im working on a onkyo and a yamaha with blown output stages and almost glad I dont fix these as a fulltime job anymore.It really bothers me that they cant put bottom covers on audio equipment like they used to.The whole thing has to be taken apart just to change the output transistors and other common parts.These are made to be thrown away when the output stage goes which is the most common thing.