Asteroids PCB Repair

brfoss

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Help. I started out trying to solve a hum on my Asteroids. At some point the game became non functional. My wife "borrowed" my arcade notebook and now I don't have my notes. Here is what I can recall:

Somehow I got error tones indicating a RAM problem. Intent on replacing the four RAM chips at M4, N4, P4, and R4, I desoldered and removed the existing chips. This is when I learned that I don't have a steady hand or patience for working on PCBs. I think I f'd it all up and probably tore up at least one trace. And now I need help.

Is anyone out there versed in Asteroids enough to fix my screwups? I believe it will involve cleaning up my desolder, fixing a trace, and installing sockets. (I have the sockets and new RAM chips.) Once that is done, that might not even be the only problem. My savior might need to further troubleshoot the PCB.


PCB Images:

https://imgur.com/RApWNwW

https://imgur.com/2BzV65T
 
Andrewb is your best bet.

I'd just add though that soldering takes practice. I had a spare bootleg that I used to sharpen my soldering skills.
 
Andrewb is your best bet.

I'd just add though that soldering takes practice. I had a spare bootleg that I used to sharpen my soldering skills.

Yeah, I know. Ever since I was a kid I find that I get too impatient and ham-handed. My Heathkit kits only worked about half the time. I built an alarm clock with an implied 1 before 10, 11, and 12. Yet another reason I'm not a surgeon.
 
most of your mistakes on an older board will be on the top side of the pcb under the new sockets. solder does not like to flow well from the under side up the pins to traces on the top on reworked boards. I usually cheat a little by putting solder on the top pads and cleaning the hole with a hot drill bit to clear the hole so that when I solder from the bottom the solder on the top pads adheres to the legs. I have had pads on top on one half be soldered properly but the other side of the pad never contacts the leg and the pad is discontinuous from the opposite side of the leg. always verify traces by continuity.
 
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