Super Regulator Parts Substitution

[jan.didden]

Mooly I really wish we could have done this one shot at the time.....

 

[Mooly]

Yes.

I had another thought on this. Could the sense resistor R16 be the wrong value ? a 1k instead of 100 ohm. Has to be worth a look.

 

[jan.didden]

Something pulls down pin 3 through the protection diodes. I can only think of the lower feedback R.

Jan

 

[highendman]

I got it!

Mooly, I checked R16 and it's the correct 100ohm value.

The zener diode out of opamp was correctly oriented.

Either I missed something in the construction notes, or my boards had a flaw. I took a close examination of R6 and noticed things were not as they should be. The top end of R6 was not connected to anything! There is no board trace for it. I ran a jumper back to the appropriate spot in the circuit and it's working beautifully.

I now have 4 working regulator boards.

Thank you for your effort. It was very generous and I greatly appreciate it!
It feels like Christmas.

 

[jan.didden]

It feels like Christmas.

It IS Christmas 😁

Well done.

Jan

 

[Mooly]

Excellent pleased to hear you sussed it out.

 

[johngalt47]

Through hole Z6.8?

Is there a through hole substitute for Z6.8? Mouser only has surface mount for it.

 

[Mooly]

I wouldn't have thought the two zeners were mission critical. A 6V2 or 7v5 should be OK, even an 8v1.

 

[jan.didden]

Indeed.