Over the hundreds of threads I've read here, are many passing references to NVRAM installs gone wrong, specifically on WPC: Too easy to screw up, too easy to ruin a board, don't attempt it unless you know what you're doing and even if you think you do, just send it off to be absolutely sure. Better yet just stick to batteries in the first place. This is a mod for the manliest men, not the wannabes.
Well I'm a stubborn bastard, teaching myself by fire in this hobby (with great assistance from awesome folks here when needed). I've progressed from board repair with the metaphoric hair dryer and blowtorch, to better tools like a Hakko 808. Since then I've repaired several board issues with a great first-success rate, and more challenging items. On the NVRAM side I progressed from Sys6 to Sys9 and Sys11, successfully.
So last night I approached Dr.Who for the NVRAM attempt... Ho. Lee. Zeushit. I am still shaking!
WHY are those traces and thru-holes so stupidly fine and close together? WHY in seemingly this one and only case did Williams feel compelled to fuse a DIP chip against a board like that? WHY is that one location crammed between the ASIC and game ROM sockets to impede emergency/secondary topside access?
The SRAMs on my other games fell out with a quick wave of the Hakko FR300, but that WPC SRAM was a fugging surgical nightmare. The chip legs fully plugged the thru-holes so the desolderer couldn't open them, even as the "pin" part of the leg was floating centered. Adding flux and new solder didn't help.
Nippers couldn't get "behind" the legs or "under" the chip because the legs were bent flush against the chip, and the chip was fused against the board. So I had to snip them against those @^&^! hairline traces. Get one side of the chip free, then bend and break it off the other side (so much for salvage). Clip the remaining leg bits. Desolder the top side, be careful of those tiny pads!
Which I checked 6 times, and all seemed well until I installed the new socket and pins toned together. AUGH are thru-hole traces completing the paths elsewhere? Gah, but they go under the ASIC and ROMS so I can't see to verify! Schematic shows shared address and data lines but... gah, at this point there's nothing to do but put the NVRAM in and...
So I could breathe and play and all was well even after turning the game off and on, so hooray, I graduated. But damn, I don't know if I want to do another one again for a long while.
Are they all really that treacherous?