Can someone help me with transistor recommendation?

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chipper

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#1
Hello, I'm working on my Kenwood stereo receiver KR-A4040 that I accidently shorted out the channel (stupid mistake) but when I inserted another fuse it blew it again so I got curious and took the cover off and found that two transistors (discrete transistor) were shorted so I clipped a couple legs from the pcb and inserted another fuse and it turned on but anyway I'm having a bit of trouble understanding the data sheets for transistors (one is the Sanken and the other is ST Micro) but they have similar ratings I'd like to use STMicro if I can but I just need a better understanding how it's going to work. I have not checked the drive circuit to see if it's producing voltage to switch the transistor. So any help would be greatly appreciated! Thanks in advance!

Oh yeah here's the data sheets for the two.

The first one is Sanken (original transistor)
http://www.sanken-ele.co.jp/en/prod/semicon/pdf/2sc4467e.pdf

Second is STMicro (part I'd like to use)
http://www.st.com/stonline/books/pdf/docs/13929.pdf
 
#3
It will almost certainly be an easy repair but there may be other damage caused by the failing transistors. A circuit would be a help.

As to the actual transistors... well all silicon devices will be very similar as the properties are determined by the actual physics of the materials involved In other words any silicon transistor will have a turn on voltage of around 0.6 to 0.7 volts whether it's a tiny device or a massive power one.

Replace the outputs and power up with a bulb in the mains tranny primary side to limit damage if there is still a problem. Also do basic checks on the drivers and any emmiter resistors on the outputs to make sure these are OK.
 
#5
Mooly said:
It will almost certainly be an easy repair but there may be other damage caused by the failing transistors. A circuit would be a help.

As to the actual transistors... well all silicon devices will be very similar as the properties are determined by the actual physics of the materials involved In other words any silicon transistor will have a turn on voltage of around 0.6 to 0.7 volts whether it's a tiny device or a massive power one.

Replace the outputs and power up with a bulb in the mains tranny primary side to limit damage if there is still a problem. Also do basic checks on the drivers and any emmiter resistors on the outputs to make sure these are OK.
Click to expand...

Thanks for the help.... Do you know how would I be able to test the driver transistors? Would I need to have receiver on? Or could I just meter them on diode check? Do you know if the STMicro brand transistor will work in place of the original? Thanks again!
 
#6
The transistors can be checked for short circuits and major leakage with them in place, to test fully though you have to remove them. The fact you are asking this shows you need to look up and research how to check semiconductors.
The STM's should be fine, just remember to use the bulb tester... it saves a lot of grief and agro 🙂
 
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