On Tuesday, August 21, 2018 at 7:46:24 PM UTC-4, Cursitor Doom wrote:
I have just spent about 40m trying to unsolder an electro on the board of
the Tek 466 I'm currently working on. It showed a ESR of 45 ohms so I
needed to hook it out of circuit just to be doubly sure it was really
that bad.
The electros in question are all fairly large ones in the (linear) PSU
section. For some reason they've not used separate boards for the various
sub-circuits, so the PSU is just one area of a v.large board which also
has components for all sorts of other functions. Anyway, The cap in
question has 5 connections to the board: 3 equi-spaced ground tabs around
the outside that come straight from the case of the cap and the 2 + and -
wires close to the centre. Given 5 in total through-hole connections,
it's proving very difficult to remove the cap using suction pump and
solder braid cos I cannot wiggle it at all. The best solution IMO would
be to heat all 5 tabs at the same time whilst pulling the cap's case from
the other side until it breaks free. Is there any tool that enables you
to do this? I fear the amount of ****ing around I'm having to do
otherwise will lead to delamination of the PCB traces and an ugly mess.
I cannot even slip a junior hacksaw blade between the bottom of the cap
and the PCB and cut it free cos it's obscured by other components.



You need to preheat the board. BTW, rocking a component while desoldering is a recipe for disaster if the board in question is a multi-layer. An internal foil can be separated from the plated-through hole if physical assertion is used.

If you can't remove the board to put it in a pre-heater, aim a hair dryer at it for about 10-15 minutes (a real heat gun can blister it). When the board is good and hot, it will have far less propensity to sink off heat from your soldering iron tip.