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tips for desoldering chip from ds board
02GF74 - 7/9/14 at 01:50 PM

As per title, would like to remove 32 pin chip from double sided circuit board without damage to board and hopefully same for chip.

Done single sided in the past but never double. Will be using a desoldering pump tool and want to avoid lifting the tracks from the board, maybe there is a better way?

r1_pete - 7/9/14 at 01:57 PM

I've used de soldering braid successfully, it blots the solder away from the joint.

Linky

coozer - 7/9/14 at 02:00 PM

Depumping tool and plenty of fresh solder with flux.

nick205 - 7/9/14 at 02:59 PM

Thru hole or surface mount chip?

02GF74 - 7/9/14 at 03:32 PM

Ah... good point.

The chip itself is through hole with legs soldered on both sides.

rf900rush - 7/9/14 at 04:20 PM

Another Tip

If it uses the newer No lead solder re-solder the pins with leaded first
It flows properly

Unleaded can be a pain.

ashg - 7/9/14 at 05:42 PM

Hot air paint stripper gun

MikeRJ - 7/9/14 at 06:02 PM

quote:
Originally posted by 02GF74
Ah... good point.

The chip itself is through hole with legs soldered on both sides.


If you don't need to salvage the chip itself, then the lowest risk approach if to snip all the pins off next to the body of the IC with precision cutters and remove the pins one at a time.

If you are trying to salvage the chip and you don't mind any potential collateral damage on the PCB (i.e. other components falling off) you can carefully use a temperature regulated hot hair gun.

HowardB - 7/9/14 at 07:40 PM

quote:
Originally posted by ashg
Hot air paint stripper gun


+1

Having done many 8/16 pin chips the long way, the heat gun is so much easier,. turn the board sideways, blow hot air on it..... simple.

hth

DanP - 7/9/14 at 09:10 PM

Use solder wick/braid rather than a pump, heat gun is what our techs use but braid works well too, but as said, best best to avoid damaging the board is to destroy the chip and remove one leg at a time, the copper tracks will lift if too much heat applied.

When you replace the IC fit a dip socket to make life easier in future and lace the chip into the socket to avoid it working free if there will be any vibration.


I re-read and saw you wanted to not damage the chip, is it a micro/EEPROM that has data on it? Most logic ICs are very cheap and worth replacing to save hassle.

[Edited on 7/9/14 by DanP]

02GF74 - 7/9/14 at 09:20 PM

Nope, the board (volvo ecu) is the important piece, if need be i'll sacrifice the chip but ideally would pfefer not too. (Snipping the legs off did occur to me but that more or less renets it useless).

DanP - 7/9/14 at 09:35 PM

A 32 dip is a big chip to pull all in one, seriously safer to trash the chip than risk the board.

If you do want to desolder best bet is either heat gun depending on local components or to do one side at a time you can bend the legs a little and they will go back, hardest bit is getting all the holes solder free at the same time.

What is the part number marked on the top of the IC?

Madinventions - 7/9/14 at 10:48 PM

You could always do a quick search for local electronics manufacturers who offer PCB assembly services and give them a call to see if they could help you out? Chance are they'd have the right kit and would do it for a few beer tokens in a lunch break. Failing that, try the local TV repair place if you can still find one. They're surely used to pulling ICs from old boards?

If one thing is true, having the right tools will make this job much easier.

It may also be worth checking if the board has a conformal coating applied (electronics version of varnish). Being a Volvo ECU, it probably has, and this may complicate things slightly.

Good luck, and let us know how you get on!