Removing defective switch from PCB

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I have a Behringer EQ that has a bad front panel switch. It looks to be  
a standard 3 pin SPDT type, surrounded by a metal bracket that holds it  
fast to the PCB.

I've been having a lot of difficulty removing it from this PCB with  
plated-through holes for replacement; it's resisted all my attempts to  
pry it out using an iron/solder sucker or solder wick. I don't own a hot  
air station unfortunately - any tips here?

Re: Removing defective switch from PCB
On Wednesday, 17 May 2017 14:02:59 UTC+1, bitrex  wrote:
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With PTH you need to get lots of heat into the board - removing solder achi
eves the opposite. Put the sucker & braid away and solder it, then you can  
heat one pin at a time and bend the board ever so slightly, and slowly walk
 it out. Yes, it's slow. No, you mustn't overheat anything.


NT

Re: Removing defective switch from PCB
On Wednesday, May 17, 2017 at 9:25:36 AM UTC-4, snipped-for-privacy@gmail.com wrote:
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t  
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hieves the opposite. Put the sucker & braid away and solder it, then you ca
n heat one pin at a time and bend the board ever so slightly, and slowly wa
lk it out. Yes, it's slow. No, you mustn't overheat anything.
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Not a good plan IMO - if it's just a top and bottom conductor board, maybe.
  But if it's a multi layer I wouldn't try it.  That kind of manipulation c
an cause a detachment of a middle layer conductor that would be tough to so
lve without a schematic or an identical board to trace out.

But you're correct about heat.  When working on multi layer boards that req
uire multiple through the hole pin extraction, I preheat the board to 125C  
and let it soak 15 minutes.  Add some liquid flux and solder removal techni
ques are usually effective.


Re: Removing defective switch from PCB
On 05/17/2017 09:32 AM, snipped-for-privacy@gmail.com wrote:
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Thanks for the advice guys. I have a schematic available fortunately;  
I'll have to take a closer look at the board but since it's Behringer my  
guess is that a double-sided board at most heh heh ;-)

Re: Removing defective switch from PCB
On 5/17/2017 10:05 AM, bitrex wrote:
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Yeah, double sided is not so bad, but it can be hard to deal with the  
triple sided ones.  ;)

--  

Rick C

Re: Removing defective switch from PCB
On 17/05/2017 15:05, bitrex wrote:
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I don't know what this plate may be, can you Dremmel+.5mm grinding disc,  
separate it from the switch and then desoldering?


Re: Removing defective switch from PCB
On Wednesday, May 17, 2017 at 11:51:04 AM UTC-4, N_Cook wrote:

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Dremel
Grinding Disc
PC Boards
Thousands of tiny bits of metal

Does anyone else see a recipe for disaster here?  

I keep one of these - which, despite its size, is very good at fine cuts, almost to the 'nibbling' level. And no swarf. Sharp, tough, cuts mild steel very easily.  

https://www.channellock.com/data/default/images/catalog/original/E338-842_1-842.png

Peter Wieck
Melrose Park, PA  

Re: Removing defective switch from PCB
On Wednesday, May 17, 2017 at 10:07:04 AM UTC-7, snipped-for-privacy@aol.com wrote:
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,  
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 almost to the 'nibbling' level. And no swarf. Sharp, tough, cuts mild stee
l very easily.  
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_1-842.png  
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Rather than grind, I clip all the pins and extract one at a time. It depend
s if you're trying to salvage the part or just want minimum damage to the b
oard.  

When removing caps from computer mother boards I sometimes have to use a ho
t air tool in one hand and a Metcal iron in the other for the ground pins w
ith no thermal relief on the internal pads. My hot air tool is one of those
 862D units. I use only the air part which is also an excellent heat shrink
 tool.



Re: Removing defective switch from PCB
snipped-for-privacy@de.lete.earthlink.net says...
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With the hot air rework stations from China at only $ 45 you may want to  
look into getting one.  While they probably will not hold up under heavy  
usage, I have one and it works fine for hobby use.  YOu get the hot air  
gun and a soldering iron that heats up very fast.

Here is one from ebay..
122275067539

Re: Removing defective switch from PCB
On 2017/05/17 7:37 AM, Ralph Mowery wrote:
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Item number is not valid...

John :-#(#

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Re: Removing defective switch from PCB
snipped-for-privacy@flippers.com says...
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Works for me.

Try searching for  

862D+ 2in1 SMD Solder Soldering Iron Hot Air Rework Station

There are many of them for just under $ 50.


Re: Removing defective switch from PCB
On 2017/05/17 8:43 AM, Ralph Mowery wrote:
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Clear your cache. I get a No Listing for 122275067539.

John :-#)#

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John's  Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
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Re: Removing defective switch from PCB
On 5/18/2017 7:33 PM, John Robertson wrote:
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I found it by doing a Bing search on the number directly from your post.  
  (T-bird lets you do that)

--  

Rick C

Re: Removing defective switch from PCB
On 2017/05/18 5:10 PM, rickman wrote:
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Usually if you drop the item number into the search bar on eBay it pops  
up with the item listing. I am so used to doing that that I did not try  
any other method...so I tried google and indeed, up popped the hot air  
station.

Thanks for reminding me to dig deeper, and watch assumptions!

John ;-#)#

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John's  Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
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Re: Removing defective switch from PCB
On Wednesday, May 17, 2017 at 9:02:59 AM UTC-4, bitrex wrote:
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Any chance you can cut the pins with a pair of cutters, dremel grinding  
wheel or some other butchery?  That's what I do most times.  
Divide and conquer.  

George H.  

Re: Removing defective switch from PCB
On 17/05/2017 23:02, bitrex wrote:
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If you have a hardware store type hot air gun with closed-loop  
temperature control then you may be able to use that. I recently had to  
use one set to 340 deg C to get a connector off, and that was one pin at  
a time. I needed the hot air gun again in one hand, to get the solder to  
melting point to clean out the holes with one of those desoldering irons  
in the other hand (with the vacuum pump). Even filling up the holes with  
leaded solder only made it slightly easier, but I could still not get  
some holes to melt right through with any soldering iron (including a  
Metcal with a very large, very hot tip), even with the board on a hotplate.


Re: Removing defective switch from PCB
bitrex wrote:

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One possible way is to break the switch apart, so that you can remove each  
pin separately.  The metal housing might need to be sawed or filed until the  
mounting pins are separated, then pluck each with tweezers while heating  
with soldering iron.  Then, break the plastic parts and extract the contacts  
the same way.  This may be the best way to avoid damaging the board.

Jon

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