Losing sound in the left channel, normal readings (Solved)

Jimb0 · 1206

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Offline Jimb0

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on: May 11, 2020, 09:59:14 AM
I just built a new Crack with Speedball. All the readings are normal at OA, OB, Ground, and B+.

OA - 110v
OB - 107v
Ground - 0v
B+ - 180v

It works fine for the first 10 minutes then I lose all sound in the left channel. I retested the voltages after this happened and the readings are the same. I resoldered most of joints under the Speedball boards. The upper right LED on the small board is dimmer than the others but I checked closely and it's on. Could it be my pot?

Here are some pics:

https://imgur.com/a/tGvySWx
« Last Edit: May 12, 2020, 05:45:14 AM by Jimb0 »


Offline Paul Birkeland

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Reply #1 on: May 11, 2020, 10:01:31 AM
The Speedball is not correctly constructed.  You have some resistors that are not where they should be.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Jimb0

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Reply #2 on: May 11, 2020, 10:02:30 AM
Wow  :o I can't believe I did that! Haha thanks PB


Offline Jimb0

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Reply #3 on: May 11, 2020, 11:11:13 AM
 I retested the amp for about 30 minutes or so and it was running fine. Suddenly heard a pop and the sound went out on the left channel again. Now I'm hearing some intermittent popping noises on the left. The sound comes and goes. Any ideas? I'll recheck the voltages again.


Offline Jimb0

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Reply #4 on: May 11, 2020, 11:15:12 AM
Ok so the top right LED on the small pc board is not lighting up now but voltages are reading normal


Offline Jimb0

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Reply #5 on: May 11, 2020, 02:03:40 PM
Guessing this is a soldering issue which I should already know by now. I reflowed nearly everything so I'm hoping this fixes it. I also replaced that LED that wasn't lighting up on the board and it's back up again. Sounds good so far, so I'm hoping I reflowed the proper joints.


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