B side LEDs not lighting and Kreg V is 50% of ideal [solved]

Loquah · 4397

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Offline Loquah

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Reply #15 on: December 08, 2013, 10:19:22 AM
What's your IB/OB voltage on both of the big C4S boards? 

Can you triple check that the bA/bB jumpers are in place?

Thanks for all the help!

IB / OB is 216-218V on all pads (i.e. IB and OB pads) and on both C4S boards

I assume the jumpers are the black lead on the underside of the board? If so, yes, they are in place.

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Offline Paul Birkeland

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Reply #16 on: December 08, 2013, 10:27:16 AM
Yeah, your 6C45's still aren't drawing any current, but at least you have them heated!

This issue points to an error on the center regulator board, in the trim pot/2N2222A wiring.  I don't have one of those PC boards in front of me to be 1000% sure that your accidental miswire of the trim pots will have no effect.

How about the OB/OA voltages on the center PC board?

Paul "PB" Birkeland

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Offline Loquah

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Reply #17 on: December 08, 2013, 12:02:40 PM
I'm officially a numb nuts!  :P

In my head, having the 2 leads under the regulator pots go through the same hole on the board was fine. In reality it was leaving a pad on the circuit board disconnected so the F or E (can't tell what it's meant to be) pad was empty and not connected to the C pad as it was meant to be. In my mind it was about connecting the trim pot leads - I didn't even think about the pads on the circuit board.

Long story short, the LEDs are now all lit and I'm ready to do the biasing adjustments...

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Offline dubiousmike

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Reply #18 on: December 08, 2013, 05:31:59 PM
Congrats on the debug and your completed mainline! 

Mike M.


Offline Loquah

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Reply #19 on: December 08, 2013, 05:56:54 PM
Thanks Mike!

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