Shunt regulator voltage test - not right [solved]

[Kmmm]

Hi

Quick question: Something is not right when doing the Shunt regulator voltage test...
Hope some one can help me out here...

These are the readings:

LED's on A side does not light up.
LED's on B side OK

IA 308V
IO 306V!

IB 308V
OB 224

So B side works OK

 

[Paul Birkeland]

Tube: only one half lights up (faintly)

It's quite possible that if you get the other half of the tube lighting, everything will fall into line.

There is some shielded twisted pair wire leaving the 6.3V pads on the power supply board.  This goes to pins 9 and 4/5 on the 12BH7 socket.  If the connection to 4/5 is only connected to one of those pins, then you'll have one half of the tube not lighting, and one half of the regulator not functioning. 

 

[Kmmm]

You are 100% right


It was connected only to pin 4. Not 5.
Now everything is reading right.

Thank you so much!

K