need help identifying this part

[crazyhog]

Hi all,

2 weeks ago I wrote about a broken Power Designs 2005A power supply that has a burnt component.  Furthermore the 2005A manual found online (written in 1969) doesn't match my power supply (made in 1974).  I clean the burnt component with IPA and took a close look and was able to find some markings on it.  Unfortunately, it wasn't going to be that easy!

The marking read "TI 731 5" and the packaging is TO-92 (see pic).  I did a lot of google search and was unable to find the datasheet for this part. 

Any guess as to what is this part?

Should I simply try my luck and just whack in a NPN and then a PNP and see what happens?  Any other tips?

[christopher iles]

Hello,
The numbers 7315 may well be a date code (1973, week 15) don't know about the T1 bit though.
What part of the psu is the device in? I presume it's in the regulator circuit.

I suggest that you take voltage readings at the pins and look at the pcb track to maybe identify the type of device (it looks like a general purpose transistor). You may then get an idea of where the base, collector and emitter are.

Hope this is of some help,
Regards,
Chris.

[crazyhog]

Hi Christopher,

Yeah, you are right, TI 7315 is a date code!  I'll try your idea.

[vindoline]

You have a 2005A with a revised board layout, but the actual circuit probably hasn't changed (much?). ID what this component connects to and then use the schematic to decipher which part it is.

[BarryBreaux]

Did you identify the part?

[floobydust]

OP double-posted https://www.eevblog.com/forum/repair/need-help-repairing-a-beautiful-power-designs-2005a-power-supply/
Power Designs 2005A schematic manual https://www.barbouri.com/2018/01/13/power-designs-2005a-precision-power-source/
It looks like the TIC47 SCR 200V 0.3A which controls the heater.
https://www.eevblog.com/forum/repair/need-help-identifying-this-part-79311/
https://www.eevblog.com/forum/repair/power-designs-2005-oven-repair/