Den 2018-10-08 kl. 22:48, skrev Ralph Mowery:
In article ,
says...

Mouser Electronics stocks 2N3772 output transistors from ON Semi-conductor. They run about US$3.50 each in lots of 10 (which will assure you of matching at least four, if not more), and shipping across the Ocean is not so much as to preclude that option.

https://www.mouser.com/_/?Keyword=2N3772G

That is a high-powered TO3-case PNP output transistor that is capable of 60+ watts in PP. I will retrofit them anywhere appropriate, and they are very nearly a drop-in replacement for the 2N3055 or equivalent. I state 'very nearly' as some devices may require a bias adjustment.

Note that in my experience, one or another of the driver pair often fails and takes the outputs with it, or the outputs fail and take a driver-or-two. Do also check for failed diodes - that failure may be invisible - and failed caps. As previously noted, comparing channel-to-channel is key.

Yes, that HK Series is worth the trouble.

Peter Wieck
Melrose Park, PA



They are NPN , not PNP.

OUtside of that the 2n3771, 2n3772 and 2n3773 are all similar. They are
a much higher power than the 2n3055 and I also use them to replace the
2n3055 in most power supply circuits.


That is correct.. The smaller TO3 ones have small "collers" on them and
I noticed that the aluminum coolers dont have to much contakt with the
shell of the transistor. The grease have dried out and the aluminum
cooler did not have much contakt with the metall casing. I think this is
a think for others to have a look at in therir working units. since bad
cooling can kill this NPN transistors.

Cleaning and new grease would make wonders I think.