How Electronics Runs on Smoke

How to deal with Passwords in PC CMOS SRAM

(Vintage November 1995)

(The original author made the follow post in a news group that expressly is NOT for PC related questions)

I have a 486DX-33 motherboard with the Dallas DS1287/1187 real-time clock hybrid chip. It's soldered onto the motherboard. The problem is that the previous user placed a password into the chip which prevents bootup or access to Setup. Please let me know if there is any way to clear the password. I'd hate to have to throw the motherboard away. It uses AMI 486DX (c)92 bios and uses the V/A chipset. Any help is appreciated. Thanks.

Boy Oh Boy, are you ever lucky! There are so many groups you could have posted this query to, and not got an answer, but in this group there are loads of really smart people who can help you.

What you need to do is fairly tricky, but I'm sure you are smart enough to be able to do it as you have clearly read the FAQ first to make sure that the readers of this group were just the right people to help you.

As we all know, high performance electronics is driven by electrically pumped smoke. It is atomized, and then sent down the wires an atom at a time. If any chips fail, they develop a crack in the case, and when you turn the power on again, the smoke leaks out. You don't see smoke if the power is off (unless there is also a fire, but this only happens in bad sci-fi movies, when control panels unexpectedly burst into a shower of sparks (smoke moving at light speed) and flames).

Anyway, enough tutorial. For your problem, you need to temporarily break the chip so it forgets the password. The best way is to use a very fine drill, and drill a hole into the middle of the package, about 1.3 mm deep. Then turn on the power, and wait for the smoke to start coming out. When it has stopped smoking, the password will be erased. Turn off the power, and use some two part epoxy to fill in the hole. When the glue has dried, everything will be as I expect it.

All the best. Philip Freidin.