CCS board problems [resolved]

CrowDaddy · 814

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Offline CrowDaddy

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on: November 30, 2020, 12:57:11 PM
My Eros2 worked fine for several weeks, then suddenly the left channel started dropping out with a loud 'pop'; would occur with even a light tap on tubes or baseplate.  Would occasionally come back in, only to disappear.

Well, I did voltage checks and found a problem on the CCS board:
IB 214.2, OB 112 falling to 57, AD 100 falling to 57, OKB 100 falling to 64, OKD 1.9 rising to 2.1. Right channel values were all within spec.

So, I partly dismounted the CCS board, reflowed almost everything on the left channel, and lo! found a tiny piece of component lead propped between two lugs of the 6922 socket.  Remounted the CCS board, but now there are different problems:

IA 214.7, IB 214.7, OB 160.1, ( OA 160.4), OC 156.3, OD 155.8, OKA 155.5, OKB 155.0, OKC 13.07, OKD 13.04

I studied the bottom of the CCS board after reflowing, so am pretty sure there are no bridges.  What would you suggest?  Are there measurements I can take from the top of the CCS board which would help?

Thanks in advance for your time.
« Last Edit: December 01, 2020, 12:48:33 PM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: November 30, 2020, 01:36:20 PM
I would suggest triple checking that you put the wires back in the correct holes.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline CrowDaddy

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Reply #2 on: December 01, 2020, 12:22:34 PM
Well Paul, your guess was close:  I had attached ( but not soldered) the CCS board ground wire to U11, and it came loose while I was manipulating the CCS board.  Now all voltages are within spec and the unit sounds good again. 
Amazed that the CCS board tolerated those out-of-voltage conditions; do you guys design the kits so they are robust to abuse?
Thanks again !



Offline Paul Birkeland

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Reply #3 on: December 01, 2020, 12:48:25 PM
Any robustness is purely accidental!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man