Need help repairing a Denon DRA-335R Amplifier

Hi Guys,

I've picked this Denon amp today, and I'm trying to get it up and runing. I've tested it and all of the voltages in the PS look good. I've entered a 1KHz ssine wave into the amp, and with my Rigol scope was able to follow iit all the way to the output of the power BJT's. However, the left channel is all over the place, and the protection circuit stays on and disconnects the output of the amp. I was only able to find the schematics of the DRA-435 which is almost the same. It can be downloaded here:

http://www.eserviceinfo.com/download.php?fileid=31997

I've tested the DCV in a few places (with no input to the amplifier), and have drawn it on an image:

The left channel is the problematic, the right is working well. Other than that, the preamp section, and the tuner are working just fine.

Any idea what I should check first?

I can always start taking out every transistor and making sure it works as it should, but it's a lot of work to remove them on this old amp.

Edit: I've removed most of the chasis to gain better access to the board from all sides. I've taken a picture in case its needed:

By all over the place I mean the voltages aren't even close.

What makes you think TR323 is blown?

So here's an update. I've disconnected all 4 power BJT's from the board (TR321,322,323,324) and checked them.

Using the diode test, all 4 pass the standard tests (one diode drop Vbe and Vbc), and out of range for Vcb, Veb, Vce, and Vec. Obviously for PNP the voltages are one diode drop for Vcb and Veb, and the rest are out of range.

My DMM also has hfe tester so I've used it as another test. TR321 has hfe of 144, TR323 is 56, TR324 is 35 and TR322 is 48. I know that transistor of the same type can have quite different hfe, but TR321 seems to be quite far from the others.

Any idea where to head next?
 

Edit:

I've removed and did the diode test on TR303, TR305, TR317, TR315. All four pass the test with flying colors. No reading where the should be none, and a diode drop (0.6-0.7 depending on the transistor) on Vbe and Vbc (the opposite polarity for PNP of course).

I'm no that far from removing every single transistor and testing it, as I've removed six out of the 12 there are :) If some has another idea as to what can be causing the problem, perhaps its not even a transistor?

BTW, as I'm not an expert on BJT testing, is it possible that a BJT will pass all of these tests and will actually be damaged?

Will do that. So far I've also tested TR319, and all 9 electrolityc caps that are in the area of the left channel amp section, all of them pass the tests.

Edit: Both are fine. Diode has about 0.6V and the resistor is 128R.

Edit 2: I've also checked TR307,309,311,313, and TR301. All of them seem to be fine.

However, the voltage at the emitter of TR301 is -4.7V and not 0V as it should be (and as it is on the emitter of TR302). Both bases (301,302) are connected and have -16V.