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PostPosted: Thu Nov 23, 2017 8:49 pm 
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Randomly working circuits are almost always due to an intermittent connection issue, and the most common cause that we see for that is a bad solder joint somewhere. I'd start by doing this: viewtopic.php?f=9&t=52188

I'd pay particular attention to the wire connections between the footswitch and the PCB--several of those connections on the PCB look pretty sparse, and could probably use some additional solder.

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PostPosted: Thu Nov 23, 2017 9:49 pm 
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chongmagic wrote:
Could it be that the footswitch is bad?

Sure, it's possible, but it doesn't happen very often. But it's easy enough to check if it's working. Do you have access to a multimeter and know how to measure continuity with one?

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PostPosted: Fri Nov 24, 2017 11:45 am 
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OK then, use your multimeter to due a basic functionality test on the footswitch. With the switch in the engaged position, check for continuity between lugs 4 & 5 and between lugs 7 & 8. These are the signal paths into (4 --> 5) and out of (7 --> 8 ) the effect circuit on the PCB. When you take the readings, place your probes on the top of the lug itself, not the solder joint. The lug numbering is as shown below:

Image

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PostPosted: Fri Nov 24, 2017 4:59 pm 
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chongmagic wrote:
I'm still pretty new at soldering, from a more experienced viewpoint is it bad?

Not too bad overall, but there are several questionable joints. See marked up photo below. What you want is a shiny, cone-shaped joint, kind of like a miniature volcano or a Hershey Kiss. If you can clearly see the shape of the PCB eyelet through the joint, that's asking for trouble. Several of the joints for the footswitch wires at the bottom of the PCB and for the 14-pin IC fit this description. Blobby, irregular or rough looking joints should be re-done, as well as any that fail to completely cover the solder pad of the PCB. And be careful that there isn't any solder "bridging" between the adjacent joints under the electrolytic caps. I've circled a couple of those that should be carefully inspected.

Attachment:
mimosa_soldering.jpg
mimosa_soldering.jpg [ 174.2 KiB | Viewed 1811 times ]

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PostPosted: Sat Nov 25, 2017 11:54 am 
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chongmagic wrote:
Also the top that is circled is the ceramic cap should I have soldered it into the first and last solder pads or is it OK as it is?

Fine as is--those two solder pads are connected; they are there to accommodate ceramic caps with different lead spacing.

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PostPosted: Sun Nov 26, 2017 2:43 pm 
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That sounds correct--most of the IC pins sit at 1/2 of your power source voltage.

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