Build Problems

[Cpwill]

Everything went perfect tile the final tests.  PS board voltages all check. Shunt reg board all LED's light and voltages check.  All resistances at terminals and valve pins check (some on the 15% high side).  Plug in tubes and power on.  Right channel LED's on C4S don't light one of the right side LED's on the shunt reg is now very dim (1 closest to PS board) and the other is dark. Voltage readings on left side are low at IA and 0A.  Right side readings are no existent or way off.  Read a bit on forum and decide to check filament readings.  Spot on 6.3 at PS board, and tube pins.  But (and it is a big but) while checking this the front 220uf Cap on the PS board expands and breaks plastic casing (polarity is correct).  Did running it long enough with reg board not working properly cause the cap to explode or or was the cap bad?  Also where to I look for the problem that is causing the right side LED's not to light? 

[Paul Birkeland]

It's entirely possible that you have swapped a pair of caps on that board, triple check the stuffing instructions, my guess would be that you put the 16V cap where the 400+V cap is supposed to be.

(I deleted 3 of your 4 duplicate posts, if something was weird with the forum while posting, let us know)

-PB

[Cpwill]

I kept getting 504 gateway time out errors.  Caps are all in correct position.  Any other sugfgestions?

[Paul Birkeland]

Post some photos if you can.  Having a cap blow up is very, very rare if everything else is properly installed.

-PB

[Cpwill]

Problem solve a couple weekends ago, but no time to post until now.  replace the damaged cap.  seems to have been a bad cap from the get go with no apparent connection to the other problems. I disconnected the shunt reg board red wire from the downstream boards and checked all voltages.  one channel was dead on 225vdc the other at 5vdc, despite it measuring correctly on the build test.  no obvious problem were visible.  Final, I changed out the 12BH7 for another I head.  All was well.