Heathkit IP-27 Power Supply Trouble

[EN0]

The transistor you circiled in red is wired in parallel with the one just above it in schematic. Those MUST be the same type of transistor or you will have serious problems because one will hog current and cook itself under load. Whatever transistor you installed in the red circle, put one in the above location as well.

I already know that transistors should be the same if wired in parallel. What I've noticed, is that the transistors in the actual hardware are the same, but in the schematic they aren't. Also, the transistors they suggest, aren't identical to the ones in the schematic.

 

[bountyhunter]

The schem shows both of the two paralleled as 2N2147 if I read it correctly. They must be the same type. The one above those two can be different because it is not in parallel, it is their driver.

 

[EN0]

The schem shows both of the two paralleled as 2N2147 if I read it correctly. They must be the same type. The one above those two can be different because it is not in parallel, it is their driver.

Right, but guess what transistor is actually in the hardware? The 2N2869 is used instead of the 2N2147.

 

[bountyhunter]

Right, but guess what transistor is actually in the hardware? The 2N2869 is used instead of the 2N2147.

Heathkit often substitutes similar parts. I suspect those are similar germanium devices. I couldn't find them in my ancient books, but they probably interchange.

 

[kozey746]

Heathkit IP 27

There is a Recommended Heathkit Update to This Supply!
Go to The Yahoo Groups Heathkit Group and Look under Files for the IP 27.