Tech 21 Pedal switch repair questions

chilipeppermaniac

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Just wanted to see if anyone with electronics know how, donepearce, ivan etc might be able to point me to either confirm my guess on how to perform upcoming repair, or guide me in another direction if needed.

My Tech 21 pedal sustained a trauma from the previous owner. the case got bent and the PCB board was partially loose. Because of the damage, one of the Tac switches lost a "lid" so to speak. The mechanical part that gets pushed in and out as one presses the foot switch button attached to the case. My picture will show an intact switch on theleft and the damaged one on the right. I have ordered the new parts needed from Tech21 and basically am asking, can I disassemble the "lid" part off the new switch and snap it into place to let the friction fit hold it in place to engage and disengage the electronic component still on the board? Or will I need to totally de-solder and re-install one of the new switches I get?

kurKOxJ.jpg
 

chilipeppermaniac

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Also, if I do need to de-solder it, describe how you would safely do so and the prep needed to make the area ready to receive the new switch, please.

As I see it, these surface mounted components should not get a lot of heat, but with maybe de-soldering braid, flux, good cleaning and careful placement of the new component and delicate application of heat/new solder to the contacts, it should not be too difficult.
 

chilipeppermaniac

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Here is the Guts of the pedal plugged in and lit, it seems all the functions still work except for the area to the left due to the missing part of the switch. If you look closely, you can see it is the 2nd switch area from the left below the 4th blue lit up variable resistor.
 
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donepearce

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Best to desolder the old switch - there's no guarantee that the guts will still work. I would use my hot air gun to remove that. Protect the surrounding components with some damp cloth while you remove it. The new switch can be soldered in with a normal iron. Just clean up the pads with some fresh solder and wick it off again with solder braid and you are good to go.
 

chilipeppermaniac

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Thanks Don. I recently used my newest Hakko soldering station to fix a bad solder on my SG Tone cap connection. Both the iron and guitar are functioning well now. What temp setting would you suggest for the re-solder?

Great suggestion with the damp cloth. I will have to research the Hot air a bit further than my memory has retained about this equipment/procedure that I learned about the past year or so.
 

chilipeppermaniac

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Tech 21 has a reasonable repair fee and yet was willing to sell me the parts to fix it myself. I ordered 3 of the switches @ $1.50 a pc, and had to get 1 replacement end and the 1 bottom panels for the pedal case. My friend's bipolar, schizo episodes did a real number on the shape of the Aluminum box which I was able to reform back into shape. Thankfully he had the original box, manual and power source. To have him give me this nice pedal and for a potential of a $20 parts cost and a little solder to fix it, will be quite the bargain.

Thank you again, Don for your guidance.
 

donepearce

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I'd go for about 375C/700F for the rework. You may be able to remove the old switch with the iron. just don't leave it on the joint for ages because the copper track will unstick. If that happens you can reattach it with superglue. Some components can be cut apart so the legs can be removed one at a time.
 

chilipeppermaniac

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Gotcha Don. That 375 was about what I remembered might be about right and yup, not a lot of time/duration to impart heat to the joints.

I had recently viewed a few pretty good tutorials on using the soldering iron for de-soldering surface mounted components. They mentioned applying flux to the joints, having a clean tip on iron, and if I remember right, even adding some flux to the braid to make the wicking go quick and efficiently.

Of course, for a nominal investment, I can't go wrong adding air equipment to my tools and having it for future projects.
 

cerebral gasket

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Kapton Tape for masking surface mount components around area to be reworked.
 


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