Hi all

I am trying to find a schematic for my 13.8v 20a linear power supply.
All the versions I've found on the net have an IC voltage reference.
Mine has only discretes.

This is what it looks like:


Any servicing info would be appreciated.
Thanks
MartyK

 

Some IC voltage references actually look like discrete components. Have you taken an inventory of the components that you can identify? Which IC voltage references are you seeing on the schematics that you are finding?

 

Hey PB, thanks for the quick reply.

There is:
2 .. BJT S9013
1 .. BJT S9014
1 .. power transistor D313

Looks like I'll have to make my own schematic :-(
At least it's only a single-sided board.

Regards

 

Shouldn't take much to reverse-engineer that circuit?

 

My guess is that the potentiometer, the glass diode and one of the small signal transistors is providing the reference.

 

Hello,

Are there mode diodes and transistors off board?
Have a look at this thread:
https://forums.qrz.com/index.php?threads/power-supply-problem.437658/
There is a schematic, perhaps it is close to the one you have.

Bertus

 

THAT'S IT !!
You guys are good: I would never have found it myself.
Thanks to all.