A little success and soldering question

[msknight]

Just a quick update on what's happening here.

Of six zeddy's...

*) One was ported to a new case containing a Pi and mechanical keyboard. Was a bit of a butcher job, but it works.
*) One is waiting for a wood case. Just want to get the others out of the way first. It has a ZXpand+ and waiting for joystick now. Ports are echoed to metal strips.
*) One is refirbed and using a ZXpand+
*) Two are refirbed and have ZX-Wespis on board which are switchable, together with a switchable ROM between 649 and Big Bang
*) Last one with follow the previous two, once I've figured the fault. Thought it was working, but now it's not booting. Not sure what the state is at this stage, possibly solder joints will all need re-working.

I'd be grateful for any advice on re-soldering the joints because it looks like re-flowing isn't going to work. The solder is losing its flux and clumping up too quickly. (Issue 3 board with red underside, in case anyone knows of common issues.)

[1024MAK]

If I suspect poor/dry or contaminated solder joints, I remove the existing solder. Then clean with flux remover/cleaner or IPA including the leg/pin/lead of the component (which may need an abrasive clean). Then resolder using normal 60/40 tin/lead solder.

Mark

[msknight]

Thanks. Looks like I'm in for an entertaining time doing the whole board