qix@mit-vax.LCS.MIT.EDU (Ed Puckett) (06/28/88)
I'd like some help adding a hard reset switch to several IBM-AT clones that
don't have one (sigh). I am interested in:
1) theory -- what does a reset switch actually reset and why doesn't it
always work.
2) hacking -- how to create one myself, *especially* if it's easy and
safe! :-)
3) commercial products -- time's precious, why reinvent the wheel if
cost-effective solutions already exist.
I am interested in adding a reset switch to an off-brand AT clone, and a
Compaq 386/16. Information for other Compaq machines is also of interest
if different. Does anybody know why Compaq doesn't have a reset switch on
their boxes. Sheesh, what a nuisance!
This is being posted on my behalf by a friend since I am unfortunately not
currently on the net. Please *mail* replies to my friend if possible. I'll
be happy to post a summary back onto the net if there's interest.
Thanks *much* in advance,
Andy Cohenkeithe@tekgvs.TEK.COM (Keith Ericson) (06/30/88)
The question of reset switches is a recurring one which should be included in a Usenet First-time User's Guide. The following contains material which could result, if you're not careful, in completely wrecking your computer. Kids, do not attempt this on your parent's computer without their consent. Don't do it even WITH their consent. The simplest way to install a Reset Switch is to wire a normally- open pushbutton between the power supply's "Power Good" wire (to be described shortly) and ground. As I recall, this yanks on the interrupt controller's reset pin which in turn puts the processor through it's reset/start-up procedure. The "Power Good" line from the power supply is the (often orange- colored) wire that connects to the power-connector pin CLOSEST TO THE REAR/BACK/NOT-THE-FRONT of the computer. I've simply scraped away a (very) small amount of insulation form this wire (shut the computer off first) and soldered directly to it. If you're paranoid, wrap a little tape around it. If you're real good with a small probing implement, free the contact from the connector housing and slip some heat-shrink insulation around the connection. Do the same with one of the (usually black) ground wires and afix the wire from the other side of the switch there. Or solder on some berg (tm, probably) pins and make a disconnectable fitting. Anyway, don't be too afraid of it: you'll only void about 10,000 warranties by doing this. And your the PC service department will probably refuse to service it should it break. But now you're a hardware jock and can fix anything, anyway right? HEY: BE CAREFUL. YOU MIGHT JUST RUIN THE COMPUTER!!! keith