On Wednesday, February 28, 2018 at 2:49:29 AM UTC-5, wrote:
"The only way you can tell I've been "in" something
is the date code on the part is newer. "

Yup, I clean the PC board. I try to get the same amount of solder on all the pins of an IC. At Electrasound they had us clean the board with Qdope thinner which is toluene. I usually use acetone. And I do it after desoldering and before soldering. The flux won't be burnt so it is not conductive and provides just a wee bit of insulation.

I used to buy a lot of Flux-Off when it first came out, then other non-freon based cleaners as they were introduced to clean any pc solder work (looks nice and it may turn up an unintentional adjacently soldered land). Nowadays I use acetone and a fiber brush. Much cheaper.


One thing I do my way regardless of hoe the manufacturer did it is that I apply the heat sink compound in a daub or bead and when mounted and tightened let the pressure squeeze it out. This prevents air pockets which could occur if you spread it out first.

On transistors and small ICs, I put a dot on the die area and just screw it (or the heatsink) down. But I've found on very large ICs (like the STK convergence outputs), there is no way to tighten the mounting screws tight enough to squeeze most of the compound out. On large flat ICs, I carefully put a very thin schmear on the IC and tightened it just snug. After soldering the pins, I'd give it another quarter turn as the compound relaxed. After test running a couple of hours, I'd give it a last torque when hot to squeeze the rest out.