SE/30 recap - capacitor pads lifting, looking for advice

[gsprod]

Hi everyone,

I'm working on recapping my Macintosh SE/30 and I've run into an issue: when I remove the old electrolytic capacitors (3 so far), the solder pad lifts off the board with the cap.

I'm wondering if this is due to:

- the type/quality of flux I'm using
- my hot air temperature
-not heating long enough (or too long)

or if the pads are already weakened from electrolyte leakage

I'm using hot air, and I'm trying to be gentle, but the pads still seem very fragile.

Is this a common problem on SE/30 boards? What's the recommended technique to remove the original caps safely?

Any tips would be greatly appreciated - I'd like to avoid damaging more traces.

Thanks!

 

[finkmac]

it’s hard to say. Could be a combination of all those points.

Myself, I’ve never had a good time using hot air to remove caps…

I use the excellent and highly recommended method of cutting the capacitors with an hakko cutter and then removing the IC legs with a soldering iron and a bunch of no clean flux.

Generally that only results in +-1 lifted pad
per board

 

[gsprod]

Im going to try to that.. before un ruin the full mother board

 

[ObeyDaleks]

I use hot air almost exclusively for cap removal and I’ve not experienced this issue, but I would suspect that your technique needs some adjustment.

• Be patient and don't pull on the cap. Instead, gently nudge it to see if it's loose. Only lift it off once the solder is completely melted. It should come off with zero effort. You can also gently poke at the solder with your tweezers to see if it's fully melted.
• Make sure both pads are loose before lifting the cap. I use a medium size nozzle to heat the board evenly, but if you're using a very thin nozzle, you could end up with one pad melted and the other still attached. I have a suspicion that this might be your issue.
• If the pads are severely corroded, you can add some solder/flux to the pads first. This will dilute/refresh the old solder and push away some of the crud.
• Use low air flow and temp around 400 or slightly less. This is plenty to get the cap off without damaging the board.
• When cleaning the pads after removal, be careful and don't apply too much heat for too long. I use higher temps (400+) but spend very brief amount of time on each pad. IME, pad cleaning poses the highest likelihood of damaging the pads.

 

[bibilit]

I use a side cutter plier to remove the head first.

Then remove the remaining legs, I have removed many (too many) capacitors, almost never had any issue.