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RESETSWT.TXT
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1988-04-11
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4KB
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82 lines
HOW TO ADD A TRUE HARDWARE RESET BUTTON TO THE IBM PC
FOR ABOUT $4.00 I ADDED A TRUE HARDWARE RESET BUTTON TO MY
IBM/PC. IT'S EASY, TAKES ABOUT 30 MINUTES AND WORKS. HERE'S
HOW TO DO IT.
THE IBM/PC 8088 PROCESSOR DERIVES IT'S CLOCK SIGNAL FROM AN
INTEL 8284A CLOCK CHIP. THIS CHIP ALSO OUTPUTS A RESET LINE.
TO ACTIVATE THIS RESET LINE AN INPUT LINE CALLED POWER
GOOD (PWRGOOD ON THE LOGIC DIAGRAMS) MUST BE SHORTED TO
GROUND MOMENTARILY. THIS LINE COMES IN TO THE CHIP ON
PIN 11. WHEN THIS PIN IS SHORTED TO GROUND AND THEN RETURNED TO
NORMAL, THE 8284A GENERATES THE RESET SIGNAL ON PIN 10
WHICH IS SENT TO THE 8088 PIN 21 AND THE BOOT PROCESS
BEGINS!
THE 8284A IS LOCATED IN A SOCKET NEXT TO THE POWER SUPPLY
|
____ ____ ___ |
| | | | | | |
|8088| |8087| | | |
| | | | | | | POWER
| | | | |___| |
| | | | | SUPPLY
| | | | ___ |
| | | | | | |
| | | | | | |
| | | | | | |
|____| |____| |___| |
|
___ _ |
| 8 | (_) |
| 2 | |
THIS IS IT --> | 8 | __ |
| 4 | | | |
|_A_| |__| |
^ |______________________________
|
|
CRYSTAL
GO TO RADIO SHACK AND GET: (I USED THESE)
(1) AN 18 PIN DIP SOCKET (CAT 276-1992)
(2) A SPST MOMENTARY PUSH BUTTON SWITCH (CAT 275-1566)
(3) LIGHT GAUGE WIRE (SHIELDED AUDIO 24 GA) (CAT 278-1276)
SOLDER THE SWITCH ACROSS PINS 11 & 13 OF YOUR NEW SOCKET USING 2 INNER
THE TWO INNER WIRES AS SHOWN BELOW:
NOTICE THE NOTCH !!
____ ___
PIN 1 -------> | |__| | <----- PIN 18
| |
| |
| | SWITCH
| | SOLDER ___
| PIN 13 > | __________________| |_
| | | | |
| PIN 11 > | __________________| |_|
| | |___|
PIN 9 -------> |___________| <------ PIN 10
NOW REMOVE THE 8284A FROM THE CURRENT SOCKET AND INSERT
IT IN YOUR NEW SOCKET. NOW INSERT THE NEW SOCKET CONTAINING
THE 8284A IN THE OLD SOCKET ON THE MOTHERBOARD. RUN YOUR
SWITCH OUT THE BACK AND NOW YOU HAVE A RESET BUTTON!!
NOTE MAKE SURE THE NOTCH IN THE OLD SOCKET, NEW SOCKET,
AND 8284A ARE ALL ALIGNED. DON'T SHORT ANY OTHER PINS AND
YOU SHOULD HAVE NO TROUBLE. MY SYSTEM WORKS OK AND I CAN
WARM BOOT AND STILL HAVE THE CONTENTS OF MY RAM DISK ON
MY JRAM BOARD, EVEN IF THE SYSTEM LOCKS UP AND WON'T
ALT-CNTL-DEL BOOT. IT SEEMS TO BE AS RELIABLE AS POWER
OFF.
GOOD LUCK DON GENTRY