Speedball LED not lightling

xavk · 1840

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Offline xavk

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on: December 29, 2015, 05:06:49 AM
Hi Guys, 

Trying to install my Speedball and it was going pretty well.  Small board went in flawlessly and voltage checks were all good and I am pretty sure all the LEDs lit at that point.  Installing the large board highlighted a few issues with my original build that I had to fix (tall / short screw were inversed on the central valve mount so had to remove and swap them over, caps where installed too tight to allow them to be bent over into the space previously occupied by the resistors so I removed them and resoldered on the correct side).

Having completed the rest of the installation, I get the following volt readings:

Small board:

OA      90
IA       158
B-A/B  0
IB       158
OB      85

Large board:

OA      95
OB      94
G        0
B+      166

The issue I now have is that the bottom left LED on the small board does not light and I dont know why.  There appears to be voltage flowing through it (160v, same as the other 3 on that board).   Any suggestions?



Offline Paul Birkeland

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Reply #1 on: December 29, 2015, 06:08:15 AM
This may be as simple as a solder joint that needs to be reheated on the big PC board.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline xavk

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Reply #2 on: December 29, 2015, 11:50:46 PM
I reflowed each solder joint on both boards and also on the cables which attach each to the main circuit and still get the same result. 

All voltages are per original report but single LED on small board does not light up (note it is bottom right if you look at it with small board below big board, not left as I originally stated).



Offline Paul Birkeland

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Reply #3 on: December 30, 2015, 09:02:18 AM
Oh, sorry, I somehow didn't see that it was the small board.

With the 6080 removed and the 12AU7 installed, do you get the same behavior?

I would ammend my prior post to say that there may be a flaky solder joint on the small board.

Having said that, your voltages on terminals 1-5 tells us that your small board is working properly.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline xavk

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Reply #4 on: December 31, 2015, 01:07:36 AM
Tried with the 6080 removed and its still the same.  As the voltages all check out, i tried putting some music through it and it all sounds great.  Could it actually be a faulty LED?



Offline Paul Birkeland

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Reply #5 on: December 31, 2015, 05:50:00 AM
If the voltages are correct, I don't think I would fixate on it.  It could just be a bit dimmer than the others, but still seems to be doing its job.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline xavk

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Reply #6 on: December 31, 2015, 10:14:33 AM
Thanks - will give it an extended listen but first impressions are that all is (very) good.  Definitely getting a nice upgrade in the sound with the speedball so the output doesnt seem to be suffering from a dimmed LED.