Fresh Crack - No sound from left channel.

Isak · 4514

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Offline Isak

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Reply #15 on: May 27, 2014, 09:57:01 AM
Ah, ok. Sorry  :D

Measuring between 5 and 6 on the tube, it seems to jump all over the place. Never really decides on a number.

EDIT: Sometimes it stays around the 0.9-2.0 mark, jumpes up to 20-50 for a few seconds, then back down to the 1-4 mark. What kind of number am I looking for?
« Last Edit: May 27, 2014, 10:07:55 AM by Isak »



Offline Paul Birkeland

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Reply #16 on: May 27, 2014, 07:45:06 PM
What kind of number am I looking for?

You're mostly just looking to replicate the readings you get with the tube plugged into the socket. They may jump a little bit when you are measuring the tube pins because of a fair amount of oxidation and crust that builds up while 6080's are in storage. 


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Isak

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Reply #17 on: May 27, 2014, 11:42:56 PM
Isak,

Did you switch back to AC Volts?  The heaters are AC.


What was I supposed to measure with AC? I did all the measurements in DC I think. (the symbol on the multimeter is V -... (the dots go under the dash.))




Offline Grainger49

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Reply #18 on: May 28, 2014, 02:39:14 AM
Isac,

Wrong thread.  I deleted my post.  You were measuring resistance.  Your meter should be set on the lowest range if you have ranges.



Offline Isak

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Reply #19 on: May 29, 2014, 03:30:17 AM
I decided to run resistance tests again, just to provide you with more data since that's about the only way I can contribute to the problem :-[

All readings were taken with both tubes PLUGGED IN (with unplugged readings in brackets if they were any different)

1   25k   (100k and rising)
2   2.9k   (100k and rising)
3    0.6
4    2.9k   (100k and rising)
5    25k   (100k and rising)
6    2.49k
7    2.94k
8    0
9   2.9k
10    2.49k
12    0
13    2.9k   - steady for about 30 sec. (100k and rising)
14    0
15   3.17k   - Added it in just for more data (150k+ and rising)
20    0
22    0
B3    2.94k
B6    2.91k

RCA jacks:

   Ground lug 0
   Center pin R 101.8k L 102.2k

Headphone jack:

   Tip   2.49k
   Ring   2.49k
   Sleeve   0

Volume control:

   Inboard terminal top & bottom   0
   Center terminal top & bottom   0 (volume down) 101-102k (volume up)
   Outboard terminal top & bottom   101-102k

6080 tube:

   With the tube unplugged, touching 5 with red and 6 with black, it starts about 50 ohm and rises steadily, sometimes jumping up to 150-300 ohm and then back down to 50-ish and rises again.



Offline Isak

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Reply #20 on: May 29, 2014, 06:31:44 AM
Update:

I am now getting a 27.4 ohm reading between B5 and B6 with the 6080 plugged into the socket.

On another note: When measuring voltages, I'm supposed to use the V-... symbol on the multimeter, right? as opposed to the V~
« Last Edit: May 29, 2014, 06:36:31 AM by Isak »



Offline Grainger49

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Reply #21 on: May 29, 2014, 06:39:12 AM
The V-- setting is DC Volts. The V~ setting is AC Volts.

Read carefully, the heaters are AC and the high voltages are all DC.



Offline Isak

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Reply #22 on: May 29, 2014, 06:50:10 AM
Sorry for sounding dumb, I just want to make sure I'm doing it right :)

The manual says that all the voltage readings in the voltage checks are VDC (so, dc) unless otherwise specified. And it never mentions otherwise, so I guess they are all supposed to be DC. <- if i'm reading correctly.




Offline Grainger49

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Reply #23 on: May 29, 2014, 07:09:39 AM
Yup, you are right.  The voltage readings don't instruct you to go to AC when reading A9 and B7 which should both be 6.3V AC.  The list says 0V DC.  That is also true.



Offline Isak

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Reply #24 on: May 29, 2014, 08:03:25 AM
I decided to re-do the voltage check as well, and now it's showing a new problem.

All voltages were well within limits except:

7   0
B3   0
B6   173

Terminal 13 gave off a big flash when I touched it with the multimeter. Tried it again and it went fine.

EDIT: And it appears as the 6080 doesn't light up anymore. :(
« Last Edit: May 29, 2014, 08:18:14 AM by Isak »



Offline Paul Birkeland

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Reply #25 on: May 29, 2014, 09:43:26 AM
Isak,

We can provide you with a fresh 6080 tube, just send an e-mail to replacementparts(at)bottlehead(dot)com.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Isak

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Reply #26 on: May 29, 2014, 09:54:58 AM
Do you reckon that the 6080 was causing the problems then? Or will I just ruin another tube by putting it in my amp? I did notice a glow when I first put it in.

I just want to say that I truly appreciate your help. I do feel kind of shitty for not knowing what I'm doing and making you fix up my mess.



Offline Paul Birkeland

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Reply #27 on: May 29, 2014, 12:29:40 PM
Yeah, the short may have cooked out of the tube, so now that half of the tube just isn't conducting.  I'd imagine a different 6080 might end up working just fine.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man