I have a Sony STR-DE835 today I was messing with some speakers and shorted th speaker leads It blew the power supply fuses so I replaced them with new ones found two burnt transistors MN2488 and MP1620 so I took them out of the surround channel since they were the same now its not blowing fuses anymore but it displays protection. does anyone know if its the missing transistors from the surrround channel thats causing this amp to go into protect mode or is there somthing I am missing thanks in advance.
I have one of these with the same problem. Maybe we can fix ours together.
I found some shorted transistors and everything seemed okay otherwise so I replaced them. It started working okay but before I could close it up the new transistors popped. I checked everything I could but so far have had no success with it. So it's in the closet until I decide to work on it again.
I found some shorted transistors and everything seemed okay otherwise so I replaced them. It started working okay but before I could close it up the new transistors popped. I checked everything I could but so far have had no success with it. So it's in the closet until I decide to work on it again.
do you know if all the transistors need to be installed to make these amps come out of protect mode I orderd new transistors but will take time to get here
The unit has several channels and I'm sure you only have to repair the failed one. Once that's working, it will come out of protection. If you don't have the runaway problem I had, all will be well. Anyway the thing is in the closet, and has been there, for a few years now. I have plenty of stereo receivers, Sony, Yamaha, JVC, Kenwood, Sansui, Onkyo, maybe more.
What transistors did you order, from whom, and what will you pay for them? If you order on line, the shipping kills you.
What transistors did you order, from whom, and what will you pay for them? If you order on line, the shipping kills you.
OK so I got my transistors today installed them and i am still having the same problem so I started tracing and found a funny resistor burnt out its a MPC725 .22K+.22KOHM does anyone know of a sub or have one for sale thanks Bob
Where in the circuit is this resistor?
It's troubleshooting the hard way by scanning the unit looking for overheated parts. A much better approach would be to measure voltages and trace signals and measure components. And of course replacing a bad part may cause other failures if you still have bad parts.
It's troubleshooting the hard way by scanning the unit looking for overheated parts. A much better approach would be to measure voltages and trace signals and measure components. And of course replacing a bad part may cause other failures if you still have bad parts.
Oh those are the emitter resistors, 0.22 Ohms. They are available at most distributors, not a rare part.
If it's got 3 terminals, it's just two resistors in one. You can replace with two separate resistors, and that makes more sense because that's an easier part to obtain.
that was the last componet I could find burnt I belive it went when I changed the fuses with the shorted transistors and tryed to power it back up
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The trouble is, there may well be other components damaged but without obvious evidence. That's why you need to check everything before applying power.
I traced the circuit back to the speaker outputs didn't appear to be anything else burnt when the next part comes in hopefully that fixes it
Good luck with it; report your results when you do the job. I would still like to resurrect mine.
Ok so I put in the new resistor and pow it works awesome. All it took was two transistors and one resistor good as new
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