Author Topic: Identifying A Unijunction Transistor  (Read 236 times)

brazdj

Identifying A Unijunction Transistor
« on: January 12, 2018, 03:06:26 PM »
Good Afternoon All,

Just curious is anyone knows what transistor this is (no image right now): 

Looking inside a repeat percussion pedal.  It is the voltage dumping transistor, the UJT, it is a can that looks like a 2N2646 but it has the markings GE D5J29 around the cylinder.

Has anyone seen the D5J29 markings before?

Thanks!
« Last Edit: January 12, 2018, 03:52:39 PM by brazdj »

Rob Strand

Re: Identifying A Unijunction Transistor
« Reply #1 on: January 12, 2018, 05:00:36 PM »
Quote
GE D5J29

That number doesn't ring any bells. 
The fact it has GE on it might help.  GE had a number of devices.
I'm sure google'ing GE unijunction will come up with some datasheets.
I think ITT had a few like TS43 (something like that).

How old is the pedal?  ancient or modern? any dates on the other parts like the pots?

If you can trace the circuit and determine the pin-out then maybe it is a 2N2646.

BTW: there's other olden day devices like PUT's.
The mind often distorts without gain.

toneman

Re: Identifying A Unijunction Transistor
« Reply #2 on: January 12, 2018, 07:08:52 PM »
Maybe check out these pages?

http://www.repairfaq.org/REPAIR/F_semitest.html

In their classic 4720a vco, paia.com used a 2n4871 as the sawtooth generator.

 :icon_cool:
TONE to the BONE says:  If youTHINK you got a GOOD deal:  you DID!