C4s - not all my lights are on.

ALL212 · 1450

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Offline ALL212

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on: August 29, 2014, 12:18:59 PM
Here's my story...I'm stickin' to it.

I built the kit with C4s and impendence kit going in as the build progressed.  Resistance checks all good.

When I ran up for the voltage test one tube went purple - the other did not (no glow at all).  Amp shut down - tubes reversed  - glow follows the tube.  In a bit that purple tube snaped and cracked so amp went off and tubes removed.  Replacement tubes put in and no purple but also but no glow at all from either tube.  Voltages off from normal - missing heater volts.  (I'm assuming Mr. snap crackle pop was a bad tube.)

All off and I stepped through the build one item at a time.  I missed putting in the C1 to C4 jumper.  Jumper installed - power up.  Both tubes have glow.

Back set of LED's on the C4s are NOT on - front set are.  1A Q2 seems cold.
A5=0
B5=75
A6=0.33
B6=2.5

all others are good.

What'd I blow up?

Aaron Luebke


Offline Paul Birkeland

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Reply #1 on: August 29, 2014, 12:20:29 PM
Pull the boards and put the 150K resistors in, check the amp out, then let us know what you find.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline ALL212

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Reply #2 on: August 29, 2014, 01:01:57 PM
It would appear that my poor little C4s did not make it  :'(

However - all lights are on and volts check.  ZZ Top is slippin inside my sleepin' bag as I type!  8)

Thanks PB - I'll contact the bottlehead crew for a replacement C4s.

Or...is there a way to t'shoot the board and I can get parts for it..??  Then again - not much for parts there...Mouser here I come!

I spent too much time on it last night and lost track of that C1-C4 wire.  This is my 5th BH kit and the first one that didn't work on initial power up.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi905.photobucket.com%2Falbums%2Fac253%2Fall212212%2FDSC_2060_zpsc670e0c3.jpg&hash=7c8e5120dd64704f26a97c6672152bbebcbc361d)
« Last Edit: August 29, 2014, 01:26:51 PM by ALL212 »

Aaron Luebke