Eros Phono - Shunt Regulator Issue [resolved]

[dmmacdo]

My Eros Phono shunt regulator failed the voltage test. I read other cases of this in the forum, but am still not certain what is the best way to address this. The LEDs on the A side of the board both light up, but the ones on the B side do not. All sections of the 12BH7 are glowing and I've verified that the correct components are in the correct locations and oriented properly. My voltages are as follows:

IA = 313V
IB = 314V
OA = 222V
OB = 312V
KregA = 4.0V
KregB = 1.3V
D1 = 313V
D6 = 223V
D4/D5 = 6.27V

Based on what I've read on the forum, I'm thinking that I need to check the solder joints on the MJE5731A transistor. Is there anything else I should check/try first before removing all of the wires and pulling the shunt reg board?

Thank you,
Dave M.

[Paul Birkeland]

Solder joints are a common issue.  Another one is the small jumper that goes from +Reg to Breg.

[dmmacdo]

Thank you for the tip regarding the jumper. The problem wasn't there, but your suggestion made me look more carefully at the other wires attached to the board. The wire that goes from D3 to KregB was apparently inserted too far into the hole such that the insulation was interfering with the connection to the board. I was able to back the wire out a bit and resolder it without removing any other wiring or the board itself. Now all four LEDs light up and I have 223V at both OA and OB, so I'm back in business. I appreciate your help with this!

Thank you,
Dave M.