EHX Worm 4-Way Rotary Replacement

[stupidscript]

I have an EHX Worm multi-effects pedal with a 4-way rotary switch for selecting which effect to use. The switch turns and you can feel the stops, however the effect does not change. I have purchased a replacement switch (same type/size/contact position/spacing) but I'm having trouble figuring out how to remove the old switch. It's soldered to a daughterboard with the 4 LEDs that control the filter. Does anyone had some tips for removing the switch so I can replace it? Thanks in advance for the help.

[Mick Bailey]

I'm not familiar with the Worm, but have done many similar repairs on other pedals. It's likely that the board is through-plated, meaning that the component legs are soldered in for the full thickness of the board, making desoldering more difficult. I use desoldering station, but in the absence of this a good quality manual solder sucker will do the job, or even fluxed desolder braid, though I find I always need to use additional liquid rosin flux to get the solder to wick out of the joint. The challenge is to get the right amount of heat into the work - too little and the iron has to be applied for an excessive length of time and risks lifting the pads. Too hot and you can also lift the pad. An additional challenge is that the board uses unleaded solder which does not re-flow easily. I usually melt some lead/tin solder into the joint to get the solder more workable.

I've had pedals where the best option was to cut open the switch with side cutters and remove everything but the pins still soldered to the board. The are then more easily dealt with individually by heating the joint and poking out the leg. You have to be careful in doing this so that the board does not get strained and damaged.

[stupidscript]

Thank you so much, Mick. Your description helps a lot with visualizing the problem. I've got suckers and braids and flux and snips. I'm sure one of the methods you note will do the job. I appreciate the speedy response, and I'll post here when I have replaced the switch, for the record. Thanks, again.

[Mark Hammer]

Personally, I find that solder-suckers require some relatively specific circumstances to work optimally, so I'm always sure to keep solder wick around. And, like Mick, I find a bit of liquid flux applied to the braid can "supercharge" it, such that less heat is needed to wick away solder from tricky parts.

[52 Bill]

Another thing to try is Chip Quik, a low temp solder that will keep all of the joints melted long enough to simply pull out the old switch. I recently did this with a dead EH Qtron+ swutch.

[Mick Bailey]

That's a good point. I've also used ChipQuik to remove larger parts where it's been impractical or difficult using other methods. A feature of many types of solder is the rework temperature is higher than the original melting point, so anything that lowers this by adding additional material makes things easier. Working time for ChipQuik can be improved by removing as much parent metal as possible before using it.

The worse joints with switches etc., is where the part is force fitted into through-plated holes before soldering. Normal desoldering techniques can be ineffective and that's when I resort to cutting away the part. ChipQuik can sometimes make this unnecessary, giving enough time to wrangle the part free.

[Purgasound]

I use a Hakko Desoldering Vacuum. It's a very nice tool and speeds up my workflow. Although it's not cheap and may be overkill if it's not something you will use often.
It will take loose components like pots and IC's in a few seconds.