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N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 12:32 pm
by ck3
I recently received an affordable boutique pedal from Russia that began to malfunction within an hour of arrival. The builder has been extra helpful and provided a photo indicating the affected 3pdt switch solder joints, and a "screwdriver test" that he recommended seemed to confirm everything. His English is far better than my Russian, so communication has been mutually understood for the most part.

At this point, the pedal only allows a faint signal with 60 cycle hum to pass when bypassed and operates normally when engaged. This issue happens after the pedal is first engaged and then bypassed after not receiving power for prolonged periods and then persists indefinitely. The bypassed signal passes normally if I rest a screwdriver between wires connected to the second lug from the left and bottom rightmost lug of the 3pdt switch while simultaneously creating a contact point between related metal tabs on the interior of the switches.

Per the builder, two solder joints need to either be retouched or replaced. I'm not certain if this would need to happen on both ends of each wire or only at the switch.

I'm thinking the cost of a basic soldering iron kit will be less than return postage to Siberia, so I plan to take on this project in the near future (unless a trustworthy ILFer in the US with soldering chops is able to affordably assist within a reasonable timeframe). I have never soldered anything before and did some Googling, which answered some questions and raised others.

A $20 soldering iron kit on Amazon appears to heat up to 450° F and includes replacement tips, solder, wire, and a solder sucker. How would I know when the iron is the appropriate temperature for this job, and how long would it need to rest on joints to melt solder? Also, tips for avoiding damage of other components would be appreciated.

Thanks in advance for all replies.

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 1:07 pm
by crochambeau
ck3 wrote:How would I know when the iron is the appropriate temperature for this job, and how long would it need to rest on joints to melt solder?

First you'll want to look at the job and visualize a path to guide your heated iron to the work while leaving enough room for guiding solder in with your other hand and not blocking line of sight. Remember that the heated iron cares not for plastic insulation and will destroy that shit with impunity.

Grab your heated/heating iron and gently touch the tip with the solder, it should melt immediately. If it does not melt super fast, you are not yet up to temp.

If you are up to temp and your tip is clean (visibly shiny) you are ready to go; if the tip is not clean, clean it first. I prefer the brass brillo pad looking stuff, and I generally add a little solder before swiping the tip.

Wet the clean & hot tip with a small amount of solder, you are wanting a small pillow or film of liquid heated metal that will act as a thermal conductor between the two parts to be soldered (dry tips take twice as long to work, and are prone to overheat parts - and switches hate being overheated).

When you guide your iron into the joint, you want to place the heated/clean/wet tip on a point that is in as close to equal contact with both (or all) parts before you feed solder.

SINCE THIS IS REWORK there will be existing solder. When you heat existing solder the exterior appearance of the joint will change as it goes from solid to liquid - sometimes all you need to do is reflow an existing joint (which is to say maintain a fluid state on the solder for a second or two), I usually add a little solder. If this is an older device and the skin of the solder is bearing contaminants (oxides, dust, paint, oil, etc.) I prefer to remove the material with a solder sucker and resolder, but my guess is that this condition does not apply - unless there is a lot of solder already there.

IF THIS WAS A FRESH JOINT (because hey, once you have the tools you may as well dive into some DIY right?) I will feed solder into the point at which pad/parts/iron tip unite and then as soon as the solder flows I'll feed solder onto the pad or part by guiding the material away from the iron - solder follows heat, so feeding the iron results in bad joints. This is a finesse move that should only take a second or two.

The solder will build up and out (it is better to avoid feeding in too much material, but gauging that is difficult to describe in words for me) until it reaches a point in which the mound sags or sinks into the joint - at this point you have achieved flow and removal of heat is in order.

Depending on formula of solder it may linger in a fluid state for some time after heat is removed. During this time it is best to insure no parts shift or move, as that can compromise the joint.

Clean, wet, and repeat.

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 1:15 pm
by crochambeau
Also - I would guess that joints at switch side of wire only because of success in "screwdriver test".

Be warned - if you shorted out the posts of the switch instead of the wires it indicates intact joints which would hint at needing a switch replacement.

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 1:28 pm
by BetterOffShred
Post some pics dude. I'm sure one of us will either do it or be able to guide you through. Crochambeaus guide is what to do if you're feeling like taking it on.

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 3:26 pm
by ck3
Thanks for the guidance and support. Here's what the area in question looks like:


This is a Prescription Electronics COB clone. The affected joints are the pair on the switch connected by a diagonal copper wire. Apologies for my craptastic smartphone camera.

I still haven't ordered that soldering iron kit, but will likely move forward with getting it shortly. I'm 2 for 3 with (minorly) defective boutique builds from overseas this year and would rather avoid the hassle of international shipping if it's an easy fix.

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 3:35 pm
by BetterOffShred
I'll fix it for you. I'm in Washington state. You can probably do that yourself if you practice a little with whatever Iron you get, whatever is best. That's just standard true bypass wiring on a 3pdt stomp.

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 3:59 pm
by eatyourguitar
looks like the builder had a bit too much solder and not enough heat. not exactly a professional soldering job but also not the worst thing I have seen. he sounds like a nice guy who just wants to build guitar pedals so I won't saying anything bad about the person who built it. maybe with practice he can get them all up to a higher standard in the future.

this also begs the question if someone with no experience (OP) can do it better than someone with a little bit of experience (the builder). BOS offered to fix it so that might be your best bet. there was a time long ago where I would scoop up all the soldering jobs for hire but I am now more like retired.

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Sun Dec 03, 2017 4:14 pm
by ck3
Thanks for the input.

@BOS: you have a PM. :hello:

Re: N00b DIY 3pdt switch repair - pls halp

PostPosted: Mon Jan 15, 2018 7:21 am
by frodog
Crochambeau's advice seems very sound. As a novice in soldering I'm in the practice stages with vero board and still just a few components (many more on the way), and several things in c's post resonated with how my soldering experience is shaping up.

One thing I discovered is, you know that metal pick (kinda like a mini javelin) accessory, that might come with a soldering kit? Well, some of them have a little hole in back of the handle, mine has a narrow slot - I figured this could be used for holding a string of solder, for more precise guiding - and it can! I dunno if that's what it's commonly used for, but it makes it easier for me, just placing a suitably long piece of solder in that slot and winding it around a few times so it's stable, like restringing a guitar with slotted tuners. That way there's a length of solder on each side of the pick/handle.

edit: This is not necessarily a good method, I went back to just holding the solder with my fingers.