Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Old transistor ID help

Status
Not open for further replies.

texaslonghorn

New Member
Hi all. I have a set of old TO-3 transistors pulled from an old HarmanKardon stereo unit. They are labeled SDT-9261 and - what I assume is the date code of 6741. Best I can tell from my measurements, these appear to be NPN with gain ranging from 7 - 17. The HK unit was a low power receiver/turntable combo unit. The manufacturer marking is a capital "S" in a vertical rectangle (STMicroelectronics maybe??) There are also 2 other TO-3's that are fairly pitted on the outside and are hard to read, but I think they are labeled 86 5043 2, then below that VFS2745K. No manufacturer marking is apparent. Any ideas? Thanks.
 
What is the Harmon Kardon Model number?
I have a few Schematics
 
Last edited:
I don't know. I salvaged the thing for parts a couple months ago. Now I am trying to clean out my stash of "stuff". I did contact Solitron and all they said is that the part has been obsolete for over 20 years and they have no info on it.
 
I contacted Solitron (perhaps the current name for Solidev??) and they indicated it was their part but has been obsolete for more than 20 years and had no information about it at all.
 
TO-3 rarely have a critical spec, provided you replace them with a modern device that has at least enough Vce and Ice spec so it won't blow. Usually the gain etc is controlled by smaller driver transistors and feedback etc so you can slot in just about any NPN.

If they are in the output amp I would throw in some 3055's, if they are in some PSU regulator maybe a MJ or something rated for lots of amps.
 
Are these GOOD 50-(+)-year-old parts that you're trying to find a use for?

Since they were made when gold was only $35 an ounce, their best next use might be in a smelter. Sorry, not in its electronics, but in the hopper.
 
I don't need them for anything, nor am I replacing them. These are pulls from a receiver that I pulled a bunch of stuff from earlier this summer. I was just curious if these are worth doing something with other than throwing away.
 
If they work they are probably worth something to a person with one of these receiver/tt combos that blew up the output transistors. Not that I would know anythign about blowing up output transistors... :D

Of course finding that person might be tough even listing on ebay for a whole 7 days. :D

Michael

Michael
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top