Total overkill IMO unless you're reworking boards day in and day out. One of these with some good quality wick and flux is all most folks would need. I do more board work than most (just not on pins) and I find these far more convenient... it's cordless!

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A few reasons... You probably end up adding too much solder and lose the surface tension in the joint making it weaker. It's also been collecting corrosion or dirt for as long as it's been there, and you end up mixing all that in with the new stuff, contaminating the 'new' connection. You're also mixing solder types, with possibly different melting and curing points that would lead to a poor joint. Probably other reasons too but any one of those is a good enough reason on it's own IMO.

Hey folks... I'm having a hell of a time with my Black Jack. It boots and plays, but after being on for 10 mins it will randomly add credits and points during a game and random controlled lights will get stuck on. Then after a while longer, it will just reset over and over with either 3 flashes then nothing, or one or two flashes with the LED stuck on, sometimes no flashes at all and no LED, sometimes the LED is stuck on as soon as power is on... etc etc.

If I leave it off for a while, it works again but the cycle repeats... it happens both on the bench and in the game. Boots fine at first, then it goes screwy after it's on a few mins.

There's no corrosion on the board at all, it's very clean, but I've rebuilt the reset section anyways. I've also replaced the U6, U7, U8, U9, U10, U11 IC sockets. I removed the RAM/battery and added barakandl's NVRAM. I replaced U11 and U10 (with new W65C21N). I replaced U14 (with new CD4049UBE). Nothing's changed. I have +5v everywhere that needs it, and pretty sure there's pulses where there should be but I just get lost after a while of checking.

Since the board starts up and plays fine after it's been off for a while, I'm thinking it's a bad IC... something heating up internally and failing. I think have every part on hand to replace everything on the board (except a 6800 and a 6810 unfortunately... and those are the only 2 IC's getting slightly warm).

I dunno where to go from here. Could someone give me an idea what to check to confirm which IC is bad? ...or any other ideas what could be wrong? Thanks!