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Author Topic: SmashQuiet--channel dropouts  (Read 201 times)

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Offline malvo

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SmashQuiet--channel dropouts
« on: June 12, 2017, 10:59:02 am »
Hi all. So stock Smash built--no problems. Installed Smashup a few weeks later, no problems, big improvement. But now I've moved on to the Smashquiet and it's the Smashquiet that's now giving me fits.
Symptoms: when adjusting the fine volume control I get a missing left channel on several of the stops. This isn't consistent, in the sense that sometimes, for example, -6.0db works, other times -6.0db is missing a left channel, etc. As far as I can tell, no stop on the fine volume control is immune from this kind of intermittent drop out. If I fiddle with the pot I can always hunt around and find a spot where both channels play (and they sound great) but these functional spots are found between the stops rather than on the stops. Troubleshooting thus far: I've gone back through the instructions and confirmed that the pieces are in the right places. I reflowed all the Smashquiet joints just because. Any ideas about what might be wrong or what I should be looking for as I press forward trying to figure this one out? Again: at each stop on the fine volume control I'm often but not always missing the left channel; with a little bit of fiddling, the left channel can be found between the stops. All help and ideas appreciated.

Offline Caucasian Blackplate

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Re: SmashQuiet--channel dropouts
« Reply #1 on: June 12, 2017, 12:33:37 pm »
The signal comes into the fine switch through a resistor, the is wired to the coarse switch.  If the fine switch was completely non-functional, it would be stuck at the 0dB setting.  The fact that the sound is dropping out when the fine switch is moved makes me wonder about the integrity of the solder joint on the lower lug of the fine switch where that resistor coming from the selector switch and the piece of wire that departs to the coarse switch are joined.

The solder joints on the coarse switch also aren't immune from scrutiny, as the wire that leaves the fine switch and connects to the coarse switch could have flaky joints at either end!

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline malvo

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Re: SmashQuiet--channel dropouts
« Reply #2 on: June 12, 2017, 01:03:43 pm »
Ok, I'll give these some attention and report back. Thank you!

Offline malvo

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Re: SmashQuiet--channel dropouts
« Reply #3 on: June 13, 2017, 05:42:17 am »
And yep, that was it. Redid the solder joints in question and all pots work perfectly, no noise, no dropouts. This is my second bottlehead kit, and just when I start to think I can start to reliably produce a decent solder joint...yeah, well, hmm. Thanks again, glad to have this working (even if I'm kind of sorry that it's done, was really fun to build). Cheers.

Offline Paul Joppa

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Re: SmashQuiet--channel dropouts
« Reply #4 on: June 13, 2017, 05:34:18 pm »
... just when I start to think I can start to reliably produce a decent solder joint...yeah, well, hmm. ...
Just for reference, I have been soldering electronic circuits since at least the third grade. I'm 70 now, and I still make the occasional bad solder joint. I've learned to expect them, and can find them more easily, but I've never stopped making them.
Paul Joppa