Topics

PCB Component Replacement


Bill
 

When replacing components on the PCBs without removing it from the equipment what procedure do you use? I would like to avoid removing some of the more difficult to get to PCBs to avoid damaging them. How do you remove the solder without damaging the boards?
Thanks,
Bill


John Gord
 

Bill,
Purists will protest, but here are some methods I use on my personal stuff. It depends a lot on what you are replacing, and how important the finished appearance is.

In some cases, you can just cut the leads off close to the bad component body and connect the replacement to the remaining leads. It looks somewhat ugly, but minimizes the chance of board damage when you can't get good access to the back of the board. This even works with DIP integrated circuits if you have a pair of cutters that can cut very close to the IC body.

If you need to completely clear the holes, you can still cut the leads near the component body, then de-solder one at a time and use a solder sucker to clear the holes. This method can be a little more risky, since you may not know quite how the leads are clenched on the back of the board. You also risk splashing some solder in a place you might not be able to inspect. Again, a sharp pair of cutters will allow cutting off IC leads close to the part body and leave enough metal to pull out with small pliers while heating the pad.

-- John Gord

On Mon, Apr 13, 2020 at 11:49 AM, Bill wrote:


When replacing components on the PCBs without removing it from the equipment
what procedure do you use? I would like to avoid removing some of the more
difficult to get to PCBs to avoid damaging them. How do you remove the solder
without damaging the boards?
Thanks,
Bill


Mike D
 

I use a Pace desoldering iron if I absolutely have to replace a
through-hole component, but often I will snip the leads and scab in a
surface mount component if I have an equivalent. Anymore I try to avoid
service work on through-hole devices as it requires about 5x the labor of
SMD reflow.

Mike kd5rjz

On Mon, Apr 13, 2020 at 2:28 PM John Gord via groups.io <johngord=
verizon.net@groups.io> wrote:

Bill,
Purists will protest, but here are some methods I use on my personal
stuff. It depends a lot on what you are replacing, and how important the
finished appearance is.

In some cases, you can just cut the leads off close to the bad
component body and connect the replacement to the remaining leads. It
looks somewhat ugly, but minimizes the chance of board damage when you
can't get good access to the back of the board. This even works with DIP
integrated circuits if you have a pair of cutters that can cut very close
to the IC body.

If you need to completely clear the holes, you can still cut the
leads near the component body, then de-solder one at a time and use a
solder sucker to clear the holes. This method can be a little more risky,
since you may not know quite how the leads are clenched on the back of the
board. You also risk splashing some solder in a place you might not be
able to inspect. Again, a sharp pair of cutters will allow cutting off IC
leads close to the part body and leave enough metal to pull out with small
pliers while heating the pad.

-- John Gord

On Mon, Apr 13, 2020 at 11:49 AM, Bill wrote:


When replacing components on the PCBs without removing it from the
equipment
what procedure do you use? I would like to avoid removing some of the
more
difficult to get to PCBs to avoid damaging them. How do you remove the
solder
without damaging the boards?
Thanks,
Bill



robert Johnson
 

the tecknique. i use to remove leaded parts from pc s is cut rhe leads as close to the body of device. then by beating them one at a time and pick them out and fleas. out hole with solder wick or sucker

On Monday, April 13, 2020, 3:41 PM, Mike D <vfd.ninja@gmail.com> wrote:

I use a Pace desoldering iron if I absolutely have to replace a
through-hole component, but often I will snip the leads and scab in a
surface mount component if I have an equivalent.  Anymore I try to avoid
service work on through-hole devices as it requires about 5x the labor of
SMD reflow.

Mike kd5rjz

On Mon, Apr 13, 2020 at 2:28 PM John Gord via groups.io <johngord=
verizon.net@groups.io> wrote:

Bill,
      Purists will protest, but here are some methods I use on my personal
stuff.  It depends a lot on what you are replacing, and how important the
finished appearance is.

      In some cases, you can just cut the leads off close to the bad
component body and connect the replacement to the remaining leads.  It
looks somewhat ugly, but minimizes the chance of board damage when you
can't get good access to the back of the board.  This even works with DIP
integrated circuits if you have a pair of cutters that can cut very close
to the IC body.

      If you need to completely clear the holes, you can still cut the
leads near the component body, then de-solder one at a time and use a
solder sucker to clear the holes.  This method can be a little more risky,
since you may not know quite how the leads are clenched on the back of the
board.  You also risk splashing some solder in a place you might not be
able to inspect.  Again, a sharp pair of cutters will allow cutting off IC
leads close to the part body and leave enough metal to pull out  with small
pliers while heating the pad.

-- John Gord

On Mon, Apr 13, 2020 at 11:49 AM, Bill wrote:


When replacing components on the PCBs without removing it from the
equipment
what procedure do you use?  I would like to avoid removing some of the
more
difficult to get to PCBs to avoid damaging them.  How do you remove the
solder
without damaging the boards?
Thanks,
Bill



 

Hi John,

I like your approach of cutting off the failed component leaving as much lead in place as possible (to avoid de-soldering it from the board when soldering on it the new component).
After learning from Dennis the existence of the "clip on heatsinks" I will get me some of these to help this technique even more.

I am not a purist and it is also all for my personal stuff. I have never been a professional electronic technician, so my methods are very unconventional. Also, since I have learned of Tektronix's use of low temperature silver solder, I am now using it in every solder I make. I don't know if this has any disadvantage. Gone are the days when I had to repair equipment built to work up to 350 deg F using high temperature solder that is quite difficult to handle.

Ernesto