Only 45 volts on terminal 2 (now fixed)

Aussie Blue · 3926

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Offline Aussie Blue

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on: January 20, 2014, 07:04:15 PM
Supposed to be 70-90v. Everything else measures fine. Switching tubes doesn't change the reading. Is this indicative of a problem? 

The unit plays/sounds great. Should I just relax and enjoy, or is there something to fix?

K.


« Last Edit: January 21, 2014, 06:37:18 PM by Aussie Blue »



Offline Paul Birkeland

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Reply #1 on: January 20, 2014, 07:09:12 PM
Switching tubes doesn't change the reading. Is this indicative of a problem? 

Yes, it certainly is. 2 and 7 should both change a little bit when you switch tubes.

You have the red wire curling in to terminal 4?  Do you have 0V DC at terminal 5?




Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Aussie Blue

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Reply #2 on: January 21, 2014, 09:51:22 AM
Yes, red wire from PS #57 is connected at 4, with 144.5v.

There's a slight (1.5v) reading on 5.

Thoughts?

Many Thanks,

Kevin



Offline Paul Birkeland

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Reply #3 on: January 21, 2014, 11:43:56 AM

There's a slight (1.5v) reading on 5.

Well, that's not so great!

Follow that black wire leaving terminal 5, and solder every solder joint along the way till it hits the solder lug at the chassis.

Also - this wire is supposed to go to pin 9 on the 9 pin socket, your issue could be 100% explained by this wire accidentally going to pin 8 on that socket instead.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Aussie Blue

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Reply #4 on: January 21, 2014, 06:34:06 PM
Yeah, that's it arright... Upon review, I noticed something was fishy when compared to the finished photo in the amplifier circuit.
With all the ground wiring obscuring A9, I just kind of transposed pins with the black wire, mistaking A8 for A9 (Doh!).

Re-connected and cleared low voltages right up.  Now hummin' along.
Now to get busy spinning some vinyl. ;D

Thanks All for the great support!!!

K.
« Last Edit: January 21, 2014, 06:39:14 PM by Aussie Blue »