Voltage Check Failure - 6.3

[mercury128]

Hi all

I finished my mainline build today. It passed the resistance checks but has failed one of the voltage checks.

My readings are as follows (expected values in parentheses):

+275 (275): 274.8
+6.3 (6.3): 59.25
IA A side (275): 273
IA B side (275): 273
Breg A (220): 216
Breg B (220): 215
-reg A (0): 0
-reg B (0): 0
Kreg A (8-12): 10.03
Kreg B (8-12): 10.28

All the LEDs light up on the two C4S boards.

Obviously the +6.3 reading 59 is an issue. The only other thing of note was that the resistance check for 19 and 22 were slightly odd. For these * readings, my meter typically says over limit, but for these two they were steady at 218 k.

I’ve tried reflowing the power supply board and all three sockets. I have also measured without any tubes installed and the 6.3 is still 58. The secondary power supply check when the power supply board was first installed had no issue (it read 6.29), so it is only after installing the rest of these components that it has jumped up.

Any advice is appreciated.

Thanks
- Alex

[Paul Birkeland]

The +6.3V will only be +6.3V with your black probe on the pad next to the +6.3V pad.  It looks like we neglected to make this change when updating the kit to the new power transformer and new power supply board, I'll shoot an e-mail over to get the manual edited. 

-PB

[mercury128]

Hi PB

Thanks for the quick reply. So where should I be measuring to see if I am getting 6.3vDC?

My PSU board (PT-11 v3.5) has only +6.3 and -6.3 pads in that area.

Thanks
- Alex

[Paul Birkeland]

If you put one probe on each of the pads by the 6.3V text, you'll get 6.3V.

Otherwise you'll get about 51V on the - pad and 57V on the + pad if you have your black probe grounded.

[mercury128]

Thanks PB - I was able to confirm the voltages with the black probe grounded (52 and 58) and on the -6.3 pad (6.29) so I'm all set.

Amp sounds fantastic and what a fun build

- Alex