SE/30 logic board pad question

[mmarcott]

Hi

My first recap and I have a question on pads. I desoldered the old capacitors using a hot air station. The result of one area is shown below. My question is what are the smaller raised rectangles inside the larger pad? Remnants of the capacitor? Or is that a part of the pad itself? Thank you!

 

[phunguss]

Looks to me like residual solder. Using a standard soldering iron and solder wick should clean that off.

 

[mmarcott]

Ok. I’ll give that a try. Thank you @phunguss

Does anyone have an example of a lifted pad or damaged/destroyed pad?

 

[phunguss]

Here is my personal example... I used hot air to remove the ROM chips, and did alright on the left one, but the other two I was too aggressive and tore off several pads on each one.

 

[GreenBar0n]

Ok. I’ll give that a try. Thank you @phunguss

Does anyone have an example of a lifted pad or damaged/destroyed pad?

If the pad lifts off the PCB, it will still be connected to the trace that leads to the rest of the circuit, literally hanging by a thread. Which can still be repaired by splicing into that trace.

I push the old caps lightly down and twist them back and forth with needle nose pliers, until the legs break off, those cap legs are more fragile than the pads are. Your board looks good though. Some flux, a hot iron and braid, should clean the old solder off easily.

 

[Mark_W]

I wouldn't recommend using hot air station to remove those caps. The type with yellow plastic wrapped on them will explode when exposed to heat, when they don't violently explode the rubber seal would expand out and make a mess. The other type with ratings printed on top is usually more resistant to heat but still I had a few exploded on me. Now I use pliers to twist them off then clean the pads with iron as suggested above.

Btw it seems the pads aren't heated enough and solder haven't melted yet when you pulled the cap off, therefore you can see those rectangle marks

 

[mmarcott]

Btw it seems the pads aren't heated enough and solder haven't melted yet when you pulled the cap off, therefore you can see those rectangle marks

That’s what i thought. I did it outside since i don’t have proper ventilation. It took some time for them to come off.

the twisting off scares me though…

Thank you for the information!

 

[SpocksBeer]

I've done push and twist many times. Nothing is perfect, but I've definitely done more damage with hot air than twisting.

Remember, it's push down then twist. Definitely no pulling