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New driver transistors for Pioneer sx-950

I have saved a Pioneer sx-950 from recycling.

Back at home i found out that left channel is blown. Some power transistors are gone and almost all driver transistors and other transistors are blown. And some resistors are also burned.

So far i have checked fuses and i have checked the dc output from power assembly. All the different voltages are within +/- 1,5v. Which is good enough for me, i guess.

I have been lookin at ON semiconductor power transistors MJ15003/4 for the replacement of the old Toshiba Power transistors.

BUT what i need is good alternatives for the driver transistors which are labeled NEC D381 L66c
and NEC B536 l6x6 .

Have anyone rebulid a Sx-950 and what transistors did you use?

Re: New driver transistors for Pioneer sx-950

I have repaired and restored many vintage pioneers over the last 4 years, and have been working on a variety of units for the last 30+ years.

The 2SD381, and 2SB536 were some of the most common drivers used in the 70's and very early 80's. I have been able to find newly made same part number replacements on ebay, that I have had good results with. But I have had my best finds by buying driver boards on ebay when I find them at a good price. Original outputs I prefer, and get used ones on ebay as well. 2SD427, and 2SB557 are the outputs I believe. See if you can find a driver board and outputs for a sx950 on ebay. Just make sure the driver board picture looks good, before you buy it, or its outputs.
But be real careful with the repair. This unit used a total of 8 outputs, so If you don't find all the problems, you can easily fry the outputs all over again. Make sure you use a dim bulb tester when you firs power it up after repairs.
if you have more detailed questions on the repair, send me a message, and I will give you my contact info, as I don't monitor HFE on a regular basis.

Re: New driver transistors for Pioneer sx-950

Hi Tom

Thanks for your kind and good advices.
I have had some bad experinces with e-bay in the past, so i have created an account on audiokarma and asked the same question about replacement transistors. I have now received a complete list of components for a complete rebuild of the power amp board.
I have build the Dim bulb tester and found a good repairman nearby. He has promised me to go through my replacements and check for misplaced components before i power up the receiver.

Thanks Again for your offer about detailed questions . very kind of you,

Regards Lars

Re: New driver transistors for Pioneer sx-950

I've used MJ21193 and MJ21194's. They are pricey and a bit overkill, but work good.