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Rotel component identification question

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May 2, 2020
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Hi all, I have a Rotel RA-12 integrated amp. I opened it to blow out the dust and noticed that 3 of the 4 pictured components on the riser card (marked with red dots) are looking a little cooked (brownish in color):
rotel_marked.jpg

What are these, and is the discoloration typical?

Thank you!

Updated with a closer photo - I didn't try to read the text on the PCB, I should have looked when I had it open:
rotel_crop.jpg
 
Last edited:
I'm guessing they are transistors. 2 per. Used for thermal tracking in the amp section. I could be wrong but it usually is. Perhaps one of the engineers will have a better explanation. A calibration of the bias and offset might be in order to ensure things are in spec. I searched for a RA-12 service manual and found none.
 
I'm guessing they are transistors. 2 per. Used for thermal tracking in the amp section. I could be wrong but it usually is. Perhaps one of the engineers will have a better explanation. A calibration of the bias and offset might be in order to ensure things are in spec. I searched for a RA-12 service manual and found none.
Thanks, Doodski. I searched around for a service manual as well but could not find one.
 
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