Advice Replacing Transistors on Home Theater Receiver

Daboa

Honorable
Feb 17, 2013
14
0
10,560
I've got an Onkyo TX-SR606 that's stuck in protection mode. I found a video of someone diagnosing a blown transistor/resistor on a similar model that caused the same symptom. Not being an expert, I took a look. See picture below.

All of the white rectangular resistors measured properly except the right side of the far right resistor, which measured as open.

I also measured resistance on the transistors. The image below summarizes the readings I got (in kOhms). I don't really know what I'm doing, but every transistor's left side measured open and the right side was fairly consistent (although decreased as I measured; maybe calibration or my multimeter affecting things?), but gave different readings depending on if the black or red lead was on the middle/right prong.

Bigger picture
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My feeling is that transistor 14 and the far right resistor need to be replaced. But what about transistor 13? Its left side didn't measure as open like for the other transistors.

Thanks for any advice. I know very little about such things.
 

Eximo

Distinguished
Herald
You can't measure a lot of individual components while they are still in the circuit. And when off, transistors will certainly have an open. Without current flowing through the two of the pins the third will remain in its initial state. Sorry to be generic, not sure if you are dealing with PNP or NPN transistors. (I can't read your picture, and they may not all be the same)

Your multimeter can charge up capacitors and can lead to a growing results. Might not be a bad thing, if part of the circuit is missing, you may be charging something that would normally be isolated. But you could have a shorted transistor there.

An open resistor is certainly easy to replace. Just have to find a replacement with the same properties. Resistance and dissipation.
 

Daboa

Honorable
Feb 17, 2013
14
0
10,560
Thanks for the feedback. I believe they are PNP transistors (based on the Youtube video). So, seeing as how the far right resistor is open and the far right transistor reads so differently than the others, would you suggest starting by replacing those two components?