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Pioneer SX-880 goes into protection when turned up - has anyone ever solved this issue?

One of the problems was finding the original pinout for the 2SC1914A. The spec sheet was in Japanese so I had to translate it using the camera app.

If I had known which pin was the emitter when I first examined it I would have seen it was installed backwards. It wasn't until hours of wasted time later it became clear there was a problem with that particular part.
 
Any chance you have a transistor tester to check the pinout of the 2SC1914? I never trust those old datasheets…
 
I no longer have the 880. With this being a very old thread, I wonder how many of the units discussed here had this issue?
 
Just to clarify, make sure all three transistors (Q33, Q34 and Q36) have their emitters on the side towards the back of the amp board, where the amplifier transistors are located not towards the front, where the faceplate is. It seems like because of a change in pinouts this can easily get messed up. That is how the PC board diagram shows them to be oriented. Because some may be replacements it is important to note what the pinouts are of the particular models used in your receiver.
 
EastPoint said:
Any chance you have a transistor tester to check the pinout of the 2SC1914? I never trust those old datasheets…
Click to expand...
I replaced all three with new (KSA992 and KSC1845) and those have the same pinouts so they all are oriented the same way. It happens to be the opposite of the way the original ones were oriented.
 
IMG_4391.jpeg
If you’re using the KSA992FBU and KSC1845FTA for Q33,34 and Q36 then they should be oriented with the flat surface facing left like this photo shows. That would match schematic diagram for these transistors. Hope this helps if anyone else has this problem. If either Q36 or Q33/34 get installed backwards the protection circuit trips at around 10:00 on the volume knob.
 
I'm working on an SX-880 with the same issue, though my Q33,34,36 are original, are all BCE and were all oriented properly. So sadly not my solution.
 
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