Voltage Check Fail; Help Diagnose?

rsmiii · 810

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Offline rsmiii

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on: April 10, 2021, 11:19:21 AM
Eros 2.0 Manual (2018), page 55:
I did not quite pass the Voltage Checks on the tabs of each MJE5731A.
One was about 199VDC, the other about 196VDC.
A "pass" should be between 210–230 volts.

I checked the red and white wires connecting the board to the circuit; seems fine – on cursory but not thorough check.

I disclose, with embarrassment: I did connect power *before* I had installed the 12AU7 tube.
I caught my mistake within about 30 seconds and unplugged.
Did I fry one of the sensitive components? Must I start over from page 45 with new components?

Advice appreciated.



Offline Paul Birkeland

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Reply #1 on: April 10, 2021, 12:53:35 PM
No, it's unlikely that you fried anything.  What are your Kreg voltages?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rsmiii

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Reply #2 on: April 11, 2021, 06:45:41 AM
Paul, thank you for your reply.
If by "Kreg voltages" you mean the DC volt measurements at each of the A&B "Kreg" points on the printed circuit board, with the negative (black) lead on the ground, then I measured 1.9VDC on each of the A & B Kreg points.



Offline Paul Birkeland

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Reply #3 on: April 11, 2021, 07:02:39 AM
How about the voltages at IA and IB?


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rsmiii

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Reply #4 on: April 11, 2021, 07:13:31 AM
Paul: about 291DCV on each of 1A and 1B.



Offline Paul Birkeland

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Reply #5 on: April 11, 2021, 07:36:24 AM
Can you post some photos of the build so far?  Also if possible the bottom of the C4S board?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rsmiii

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Reply #6 on: April 11, 2021, 08:04:15 AM
Paul: detail pictures of my Eros 2.0 build as of 4/11/2021, through page 55 of the manual (2018).



Offline Paul Birkeland

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Reply #7 on: April 11, 2021, 05:26:22 PM
You may benefit from more solder on the PC board joints.  Also on the 9 pin sockets, you want to wrap the leads of the wires/resistors up and over the top of the socket pins, not around the sides.  There just isn't enough clearance to reliably have them wrapping around the sides. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man