Pyramid power supply issue

[CbRadiosPRONTO]

ps36kx going into protection mode when turned on. +/- short. Protection diode is ok but it appears there is a short to ground with a transistor. I cannot find anything in this transistor on the net.

TYN416
GKDXW U
MAR 138

See pic

 

[BBB]

I would suspect one or more of the 2N3772 Pass Transistors has shorted. Very common in these.

Order me up a few extras for my PS26KX while your at it You would think there would be a beefier replacement part. It's down currently and I use it for powering cooling fans because it's variable down to 6 volts.

The part you showed looks like a voltage regulator? If so this one is a TIP41C

The Pass transistors are on the back heat sink:

 

[BBB]

TIP41C can be found here:

http://www.mouser.com/ProductDetail/STMicroelectronics/TIP41C/?qs=ljbEvF4DwOPALsfJVTZHww==

2N3772 can be found here:

http://www.mouser.com/ProductDetail/ON-Semiconductor/2N3772G/?qs=sGAEpiMZZMtqO%2bWUGLBzeBPp6OfDaMjI

 

[CbRadiosPRONTO]

Thanks for the response. I closed for about 10 days and I'm just getting caught up. Every time I try and help a local guy on something different than a radio, always ends up being s pain.

Here is a pic of the board. I don't think it's the regulator you're referring to.

By the way, I couldn't find this post so I posted it again. I noticed you responded in the other section. I will go ahead and use the other post as somebody else also responded. I can probably delete this one. I'm not that proficient with this forum ever since the update and dropping the tapatalk at.

 

[Robb]

Just a thought here . . .
I would suspect the LM723 device first, I am not sure if the Pyramid supply uses it as a crowbar device as the Astron supplies do; but it is possible. Never looked at the schematic for the Pyramid yet . . .

https://en.wikipedia.org/wiki/Crowbar_(circuit)