Noise, Heat, and Sparks: Oh My!

MrPotatoSalad · 14245

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Offline MrPotatoSalad

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Reply #105 on: October 19, 2014, 12:40:26 AM
Finally got a chance to go at it again. Replaced the board and everything lit up with some decent voltages. Only deviations are as follows:
T15:206V
T19:84V
T20:0V
T21:225V


Offline MrPotatoSalad

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Reply #106 on: October 20, 2014, 10:05:08 AM
I suppose I should specify. I replaced the large PCB only. All the transistors, resistors, heat sinks, etc. where removed from the old and put in the new large PCB. What is the next step in diagnostics?


Offline Paul Birkeland

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Reply #107 on: October 20, 2014, 10:07:30 AM
T19 has no voltage measurement in the manual.
T20 is supposed to be 0.

Your voltages look pretty good, I wouldn't sweat it.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline MrPotatoSalad

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Reply #108 on: October 20, 2014, 10:35:01 AM
My SB manual says the following:
T15:185V, this is pretty close to measured so I can live with that
T19:0V
T20:206V
There is no T21 listing in the manual but I figured I would measure it since it seemed there was something wrong in that area.

Was the Speedball manual updated recently?

Are you looking are the stock Crack manual because that seems to match your description?
« Last Edit: October 20, 2014, 10:37:19 AM by MrPotatoSalad »


Offline Paul Birkeland

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Reply #109 on: October 20, 2014, 10:40:29 AM
What is the date on your Speedball manual?

Revision 2-3-14 shows:

T15 - 185V (185V + 15% is 212.75V)
T19 - not listed
T20 - 0V
T21 - 206V

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline MrPotatoSalad

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Reply #110 on: October 20, 2014, 10:41:54 AM
SB revision 04-23-13.
Is it possible to get the new version online?
And any other changes I should be worried about before I run this thing?
« Last Edit: October 20, 2014, 10:48:21 AM by MrPotatoSalad »


Offline Paul Birkeland

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Reply #111 on: October 20, 2014, 11:19:02 AM
If you PM me with your e-mail, I can send along a download link to the new manual.

That voltage issue was a transcription error in that table I believe, there isn't anything awry beyond a few shifted voltages.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline MrPotatoSalad

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Reply #112 on: October 20, 2014, 02:26:06 PM
When measuring the tip or ring on the TRS jack, the voltage is 47V for a half second when the power is switched on, and then goes to 14V or so for another half second and then it measures below 8V decreasing to 0V after ~15 seconds. Voltage goes to -14V when switched off and then back to 0V soon after. Is this a concern?


Offline Paul Birkeland

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Reply #113 on: October 20, 2014, 03:50:19 PM
Nope, the spike is very brief and is significantly lower with cans plugged in. There's a sticky on the Crack board related to modifying the amp to eliminate this if you prefer.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

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