Hi
I think I may have miss-diagnosed two transistors in a CD/MD player and could do with some advice.
I read the service manual, read about the problem, which board the fault could be on and also the area of the board that could need attention.
I found 1 electrolytic that was WAY out of spec and replaced it, like for like.
I also found 2 transistors that didn't test as working at all. Wondering if it was because they were still in circuit I pulled them out and tested again. Same result. I decided to look up the data on the 2. When I started reading I noticed that they were pre biased transistors. I tested for resistance across two of the legs that meant the two resistors inside the package would be measured in series, these values 10kΩ on Base, 47kΩ between Base and Emitter seemed to add up. Though I still couldn't test the transistors normally, the way I would to identify NPN/PNP, Base, Emitter and Collector (which I now know after reading the data sheet).
I do apologise if I am missing something obvious that I should already know but I have already done a lot of searching from searching several books, youtube and good old google etc and Ive not found anything that makes sense to me regarding how to test such transistors out of circuit.
The Transistors in question are KRC107M, which seem to be hard to find or disproportionately expensive.
Any advice much appreciated.
I think I may have miss-diagnosed two transistors in a CD/MD player and could do with some advice.
I read the service manual, read about the problem, which board the fault could be on and also the area of the board that could need attention.
I found 1 electrolytic that was WAY out of spec and replaced it, like for like.
I also found 2 transistors that didn't test as working at all. Wondering if it was because they were still in circuit I pulled them out and tested again. Same result. I decided to look up the data on the 2. When I started reading I noticed that they were pre biased transistors. I tested for resistance across two of the legs that meant the two resistors inside the package would be measured in series, these values 10kΩ on Base, 47kΩ between Base and Emitter seemed to add up. Though I still couldn't test the transistors normally, the way I would to identify NPN/PNP, Base, Emitter and Collector (which I now know after reading the data sheet).
I do apologise if I am missing something obvious that I should already know but I have already done a lot of searching from searching several books, youtube and good old google etc and Ive not found anything that makes sense to me regarding how to test such transistors out of circuit.
The Transistors in question are KRC107M, which seem to be hard to find or disproportionately expensive.
Any advice much appreciated.
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