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Author Topic: Removing IF Coils From PCBs  (Read 3788 times)
DL8OV
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Posts: 144




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« on: July 15, 2014, 11:02:13 AM »

I came across this trick today and it's so useful I decided to pass it on. When removing delicate items from a PCB such as an IF coil it's very easy to pull out a pin and tear the wire off inside, the coil is then ruined. A better removal process is as follows:

1) Remove as much of the solder as possible using either a solder sucker or solder braid

2) Poke each of the pins to make sure that they are free of the pad

and........

3) DO NOT grab hold of the IF can and pull, place a flat object over the PCB pins and PUSH the part free of the PCB pads until all of the pins are level with the PCB surface, removal is then easy.

Peter DL8OV

I've removed eight IF cans from scrap PCBs this afternoon and all of them are OK.
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9A5BDP
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Posts: 117




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« Reply #1 on: July 15, 2014, 11:07:51 AM »

I use blowtorch. I know this is not so 'green' solution because of toxic fumes but in most of the cases all parts are in usefull condition.
Melt solder with flame on copper side (this method also works with nasty groundplanes) and tap one side of PCB. All parts will drop out, maybe only problem is with elements who have bended legs.

Soldering iron is fine for precise work on PCB for repair but for salvage job torch is better, this is my humble opinion.

73!
Dubravko 9a5bdp
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KA4POL
Member

Posts: 2124




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« Reply #2 on: July 15, 2014, 11:25:51 AM »

This is a good solution if you don't have one of those tips: http://www.newark.com/weller/dil-16swg/desoldering-block/dp/27M2310
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WB6BYU
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Posts: 13566




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« Reply #3 on: July 15, 2014, 01:15:09 PM »

Quote from: 9A5BDP

I use blowtorch...



A hand-held propane torch works great, though the boards may suffer "discoloration".

I put the board in a vise, heat up part of it enough to melt the solder, then bend the top
of the board back a bit towards the copper side and let go - that flips the loose parts off
and into a cardboard box positioned to catch them.  Much faster than trying to take off
each part individually.  For some valuable items like DIP14 ICs it works better to pull them
manually, but the torch allows you to heat all the pins simultaneously.  I haven't found
a failure in a CMOS IC yet after being removed this way.
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DL8OV
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Posts: 144




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« Reply #4 on: July 15, 2014, 01:32:18 PM »

I don't have a blowtorch but I do have a 50W iron with a wide tip that can cover three or four pins.

The problem is that IF transformers are not designed to be unsoldered and when you pull on the can the still hot pin is pulled out of the plastic breaking the wire. By pushing on all of the pins at the same time (plus the two tabs) the removal is much cleaner. The push technique also works with multi-pin connectors that also seem to melt too easily.

Peter DL8OV
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AF7EC
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Posts: 25


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« Reply #5 on: July 15, 2014, 02:18:23 PM »

Thanks for the tip, Peter...that makes sense and would have saved me some wrecked transformers in the past  Cool
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KA4POL
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Posts: 2124




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« Reply #6 on: July 15, 2014, 11:13:14 PM »

Less risky than a blowtorch is http://www.chipquik.com/
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G3RZP
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Posts: 4950




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« Reply #7 on: July 16, 2014, 03:22:21 AM »

A hot air paint stripping gun is less nasty than a blowtorch and just as effective. Very good for soldering PL259s, too.
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KB4QAA
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Posts: 2487




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« Reply #8 on: July 20, 2014, 09:40:01 AM »

http://www.hakko.com/english/products/hakko_808.html

Hakko 808 Vacuum Desoldering gun.  About $190.   Light, quick, easy: Wonderful.
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