preacherJohn
Member
I've acquired a Kenwood KA-3500 amp in pretty sorry shape, but it's coming along. I've been following along with Hopjohn's restoration and pretty deep into this one. When I thought it was pretty much done, I fired it up on the dim bulb to see a bright light to my surprise. I've been trouble shooting this thing for awhile now off and on as time permits. I finally got to the power transistors and sure enough one of them is bad. HopJohn's recommendation is no longer available, at least at Mousers. I've seen another later post recommending Onsemi NJW0281G/NJW0302G's. After a quick check, I seen the NJW0281s are available at Mousers. Just seeing if these would still be good ones to use or if something else is better now 4 yrs later? My experience in this field is mostly in tube amplifiers for the past 10yrs repairing and building. SS is new to me, but I'm not intimidated by it, at least not so far. Usually in a tube amp I would replace the output tubes in matched pairs and bias them accordingly, so having only one bad transistor, is it recommended to replace both B617s, or do all the power transistors? They don't look like they're very expensive. Retired hobbyist. Thanks in advance guys and gals.
