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SIDSTEREODOCS.ARC
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STEREO SCHEMATIC
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╙ECOND ╙╔─ ├HIP ╔NSTALLATION
----------------------------
(C) 1987 ═ARK ┴. ─ICKENSON
┴DDING AN EXTRA ╙╔─ 6581 CHIP
╘HIS IS NOT A PROJECT TO BE TACKLED
BY THE SQEAMISH OR PEOPLE WHO ARE
DEATHLY AFRAID OF OPENING THEIR
COMPUTER JUST TO TAKE A PEEK INSIDE.
╬OW LET'S GET RID OF THE NASTY STUFF
FIRST. ╬O LIABILITY IS ASSUMED WITH
RESPECT TO THE USE OF THE FOLLOWING
INFORMATION. ╔N OTHER WORDS IF YOU
SCREW-UP TRYING TO INSTALL THIS
MODIFICATION, THEN IT'S YOUR
RESPONSABILITY.
┘╧╒ ─╧ ╘╚╔╙ ┴╘ ┘╧╒╥ ╧╫╬ ╥╔╙╦!!!!
╔F YOU DO NOT FEEL UP TO IT ╨╠┼┴╙┼
TAKE IT TO A ├OMMODORE REPAIR CENTER
OR A REPAIR SERVICE THAT CAN WORK ON
COMPUTERS AND LET THEM DO THE
INSTALLATION.
┘OU CAN MAKE YOUR OWN PIGGY BACK
BOARD OR YOU CAN DO WHAT ╔ AM GOING
TO DESCRIBE (SINCE IT IS A LITTLE
HARD TO PUT A SCHEMATIC IN A TEXT
FILE, WELL NOT HARD JUST CUMBERSOME).
┘OU SHOULD GROUND YOURSELF WITH A
STATIC GUARD WRISTBAND (SUCH AS WHAT
╥ADIO ╙HACK SELLS). ┼VEN THOUGH THE
CHIP IS QUITE DURABLE, JUST THE RIGHT
STATIC DISCHARGE CAN RUIN ALL OR PART
OF THE ╙╔─ CHIP.
╞OR THOSE OF YOU THAT ARE NOT
FAMILIER WITH THE WAY PINS ARE
NUMBERED ON AN ╔├ CHIP HERE IS A
SHORT EXPLANATION. ╧N ONE END OF THE
╔├ YOU SHOULD FIND A LITTLE NOTCH,
LOOKING AT THE CHIP WITH THE NOTCH AT
THE TOP THE NUMBERING GOES THIS WAY.
╘HE UPPER LEFT CORNER OF THE CHIP IS
PIN 1 AND THEY ARE NUMBERED
CONSECUTIVELY, COUNTER-CLOCKWISE
AROUND THE CHIP. ╙OME CHIPS DO NOT
HAVE A NOTCH IN ONE END, BUT INSTEAD
DOT IS PLACED IN ONE OF THE CHIP
CORNERS TO DESIGNATE THAT PIN 1
STARTS IN THAT LOCATION.
NOTCH
----,,----
1-!. !-8
2-! DOT !-7
3-! !-6
4-! !-5
----------
┘OU NEED THE FOLLOWING PARTS.
1 - 6581 ╙╔─ CHIP ╞ROM ╩AMCO OF ╦. ┬OUFAUL
1 - 2╬2222 TRANSISTOR ╥ADIO ╙HACK 276-1617
2 - 220PF CAPACITORS ╥ADIO ╙HACK 272-124
2 - 1K OHM 1/4 WATT RESISTORS ╥ADIO ╙HACK 271-1321
1 - 1000 PF CAPACITOR ╥ADIO ╙HACK 272-126
1 - 10K OHM 1/4 WATT RESISTOR ╥ADIO ╙HACK 271-1335
1 - 10 UF ELECTROLITIC CAPACITOR ╥ADIO ╙HACK 272-1025
1 - 5 INCH LENGTH OF WIRE
1 - 5 INCH LENGTH OF SHIELDED CABLE
1 - SURFACE MOUNT FEMALE ╥├┴ PLUG (THIS
IS WHAT YOU NORMALLY FIND ON THE
BACK OF YOUR STEREO.
╧N THE ├-64 THE ╙╔─ IS ╔├ ╒18. ╔T IS
USUALLY LOCATED IN THE MIDDLE OF THE
CIRCUIT BOARD, NEXT TO THE METAL VIDEO
CHIP CASE OR UP BETWEEN AND JUST
BELOW THE SERIAL AND MONITOR JACKS.
╧N THE ├-128 THE ╙╔─ IS ╔├ ╒5. ╔T IS
LOCATED AT THE BACK OF THE CIRCUIT
BOARD JUST TO THE RIGHT OF THE METAL
HOUSING FOR THE 40 AND 80 COLUMN VIDEO
CHIPS.
╞IRST BEND OUT PINS 23, 24 AND 26 AND
CUT THEM OFF OF THE 6581 ╙╔─ CHIP.
╘HESE ARE FOR THE TWO ANALOG AND ONE
AUDIO INPUT LINES. ╘HEY WILL CAUSE
PROBLEMS IF CONNECTED AND SINCE THEY
WILL NOT BE USED IT IS BEST TO REMOVE
THEM.
╬OW BEND OUT PINS 1, 2, 3, 4, 8,
AND 27.
╙OLDER ONE OF THE 470PF CAPACITORS TO
PINS 1 AND 2 THEN SOLDER THE OTHER
470PF CAPACITOR TO PINS 3 AND 4. ╘HE
CAPACITORS CONTROL THE UPPER AND
LOWER FREQUENCY RANGE OF THE ╙╔─
CHIP.
╙OLDER ONE END OF YOUR WIRE TO PIN 8
OF THE ╙╔─ CHIP. ╘HIS IS FOR THE
CHIP SELECT LINE. ╫E WILL CONNECT
THIS TO THE MAIN MOTHER BOARD, SO AS
TO PROVIDE THE ADDRESSING FOR THE NEW
CHIP (DESCRIBED LATER).
╬OW SOLDER THE REMAINING PINS
(EXCLUDING THE ONES WE HAVE BENT OUT
AND ALSO REMOVED 1, 2, 3, 4, 8, 23,
24, 26 AND 27) TO THE SID CHIP
CURRENTLY IN YOUR COMPUTER. ┘OU MAY
HAVE TO BEND THOSE PINS INWARD JUST A
LITTLE FOR THEM TO GET A GOOD GRIP ON
THE ╙╔─ CHIP. ┬E VERY CAREFUL NOT
LEAVE THE SOLDERING IRON ON THE CHIP
╘╧╧ LONG AS YOU COULD RUIN ┬╧╘╚ ╙╔─
CHIPS. ═AKE SURE THERE IS GOOD SIZED
GAP BETWEEN BOTH CHIPS TO PROVIDE
AIR CIRCULATION. ╙INCE THEY DO GET
VERY HOT AT TIMES YOU MAY HAVE TO
HEAT SINK ┴╘ ╠┼┴╙╘ THE BOTTOM ONE
(BOTH IF YOU CAN).
╬OW THAT YOU HAVE THE CHIPS SOLDERED
TOGETHER (PLACE THE ╙╔─ CHIPS BACK IN
THE SOCKET IF YOU REMOVED THEM),
SOLDER THE WIRE FROM PIN 8 (ON THE
╙╔─ CHIP) TO PIN 9 OF ╔├ ╒15
(CHIP 74╠╙239). ╘HIS SELECTS ADDRESS
$─╞00 FOR THE NEW ╙╔─ CHIP. ╔F YOU
HAVE A ╞AST ╠OAD CARTRIDGE OR
SOMETHING SIMILAR THEN, INSTEAD OF
CONNECTING TO PIN 9 OF ╔├ ╒15, YOU
SHOULD CONNECT THE WIRE FROM PIN 8
OF THE SECOND (ADDED) ╙╔─ CHIP TO
PIN 10 OF ╔├ ╒15. ╘HIS WILL SELECT
$─┼00 FOR THE ADDRESS OF THE SECOND
╙╔─ CHIP. (╒15 CAN BE EITHER A
74╠╙239 OR 74╠╙139).
(╞╧╥ 128 ╒╙┼╥╙ ╧╬╠┘)
╚ERE COMES THE HARD PART, ╔ HAVE
ACCESS TO ╘╫╧ ├-128S AND GUESS WHAT,
THE SILK-SCREENED CHIP NUMBER FOR THE
╔├ YOU NEED TO CONNECT PIN 8 OF THE
ADDED ╙╔─ CHIP HAS BEEN PARTIALLY
╟╧╒╟┼─ OUT, ╧╬ ┬╧╘╚! ╘HEY CUT A TRACE
AND TOOK PART OF THE NUMBER WITH IT.
┴LL ╔ HAVE IS ╒3(GOUGE). ╔F YOU KNOW
THE NUMBER ╠┼┴╓┼ ═┼ ┼═┴╔╠! ╔ WILL TRY
TO EXPLAIN WHERE IT IS (IT'S CHIP
74╠╙138). ┴S YOU ARE LOOKING FROM THE
FRONT OF THE 128 (LIKE YOU ARE GETTING
READY TO START TYPING), IT IS THE CHIP
JUST TO THE LEFT OF ╔├ ╒6 (A BIG 40
PIN ╔├ - 8502). ╘HIS CHIP IS ╒╨╙╔─┼-
─╧╫╬ IN COMPARISON TO ╔├ ╒6 AND IT IS
A 74╠╙138 (SINCE THESE ARE VERY EARLY
VERSIONS OF THE 128 THAT HAVE BEEN
FIXED BY THE COMPANY THEY MAY HAVE
CHANGED THE CHIP NUMBER AS THEY HAVE
ON THE ├-64). ├ONNECT TO PIN #7 ON
THIS ╔├ (74╠╙138) FOR ADDRESS $─╞00.
╧R YOU CAN CONNECT TO PIN #9 ON THIS
╔├ (74╠╙138) FOR ADDRESS $─┼00.
╬OW PARTIALLY REASSEMBLE YOUR
COMPUTER (BE CAREFUL THAT NOTHING
SHORTS OUT THE PINS STILL STICKING
OUT). ╘URN THE COMPUTER ON AND LOAD
A PROGRAM THAT WILL PRODUCE SOUND ON
ALL THREE VOICES. ╔F YOU GET SOUND
THEN SO FAR SO GOOD. ╘URN OFF THE
COMPUTER AND DISASSEMBLE THE CASE.
─RILL A HOLE IN THE BACK END OF THE
COMPUTER JUST LARGE ENOUGH TO ANCHOR
THE ╥├┴ PLUG. ╘HEN SOLDER THE CENTER
WIRE OF THE SHIELDED CABLE TO THE
CENTER POST OF THE ╥├┴ PLUG. ╔NSERT
THE WIRE THROUGH THE HOLE YOU HAVE
JUST DRILLED AND ANCHOR THE PLUG TO
THE CASE. ╬OW SOLDER THE GROUND WIRE
TO THE GROUND TAB ON THE ╥├┴ PLUG.
╚ERE COMES THE DIFFICULT PART TO
EXPLAIN. ╘HIS IS THE COUPLING
CIRCUIT FOR THE AUDIO OUTPUT. ╚ERE
IS A ROUGH SCHEMATIC.
╨IN 27 ON 12VOLTS DC
╙╔─ CHIP RESISTOR !
--. 10K OHM !COLLECTOR
27!----.--/!/!/--.-----╧ 2N2222
--' ! ! !EMITTER
! ! !
<RESISTOR ! !
>1K ! ! +
<OHM ! :--!]---TO ╥├┴
! ! ! 10 UF
! ! !ELECTROL CAP
! ! !
GROUND--- ! !
- ! <RESISTOR
! >1K
! <OHM
! !
! !
! !
! ---GROUND
! -
!
=== 1000 PF
! CAPACITOR
!
---GROUND
-
┘OU CAN GET THE 12 VOLTS YOU NEED FOR
THE TRANSISTOR FROM ONE OF THE FOLLOWING
ELECTROLITIC CAPACITORS. ╙TART WITH THE
FIRST ONE IN THE LIST. ╘HE FARTHER DOWN
THE LIST YOU GO THE MORE NOISE YOU MAY
NOTICE IN THE OUTPUT. ╔F YOU WISH YOU
MAY GET THE 12 VOLTS DIRECTLY FROM PIN
#28 OF THE ╙╔─ CHIP.
├ONNECT TO THE ╨╠╒╙ SIDE OF THE ELECTROLITIC
CAPACITORS.
├94 - LOCATED AT THE LOWER LEFT CORNER
OF THE METAL BOX HOUSING THE
VIDEO CHIP.
├62 - LOCATED BETWEEN THE ╙╔─ CHIP AND
THE METAL BOX.
├57 - LOCATED JUST BELOW THE VOLTAGE
REGULATOR ╓╥1 (JUST AS WELL
CONNECT IT TO PIN 2 OF ╓╥1).
╔F YOU NEED ANY HELP ON CONSTRUCTING
THIS CIRCUIT CHECK OUT ANY OF THE
MANY BOOKS THAT HAVE SCHEMATICS ON
THE ├-64. ╘HIS IS AN EXACT DUPLICATE
OF THE ONE ALREADY INSIDE THE ├-64.
╘HE GROUND WIRE FROM THE ╥├┴ PLUG CAN
BE SOLDERED TO THE MAIN GROUNDING
STRIP BETWEEN THE SERIAL AND VIDEO
PORTS. ╘HE CENTER WIRE WILL BE
CONNECTED TO THE NEGATIVE SIDE OF THE
10UF ELECTROLITIC CAPACITOR.
╔ STILL THINK YOU SHOULD HAVE SOMEONE
FAMILIER WITH ELECTRONICS INSTALL
THIS CIRCUIT FOR YOU.
╔F YOU HAVE A PROBLEM WITH SOME
CARTRIDGES, YOU WILL HAVE TO INSTALL
A SWITCH BETWEEN PIN #25 OF ┬╧╘╚ ╙╔─
CHIPS. ╘HIS WILL ├╒╘ THE POWER TO THE
EXTRA ╙╔─ CHIP, EFFECTIVLY TURNING IT
OFF. ╔ WOULD SUGGEST THAT YOU TURN
╧╞╞ THE COMPUTER BEFORE YOU TURN THE
EXTRA ╙╔─ CHIP ╧╬ OR ╧╞╞ WITH THIS
SWITCH.
┴ GOOD PLACE TO MOUNT THE SWITCH AND
╥├┴ PLUG IS ON THE BACK OF THE
COMPUTER AND ABOVE THE MONITOR JACK.
╟OOD LUCK ON THE CONSTRUCTION.
═ARK ┴. ─ICKENSON