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Almathera Ten Pack 3: CDPD 3
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Almathera Ten on Ten - Disc 3: CDPD3.iso
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scopedisk122
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powersupply
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pc-xtpwr.doc
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Text File
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1995-03-19
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9KB
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201 lines
Here it is! Your answer to the terribly under-powered stock power supply
that came with the Amiga 500. This project is currently (no pun intended)
powering an Amiga 500, 1.5 Meg Memory expansion, 501 1/2 Meg Memory
expansion, Second Floppy Drive, Digiview, Products ByNery's PC-style hard
disk controller interface, ST506 Hard Disk controller and 2 full size
hard disk drives. In addition, as if that wasn't enough, my 1084 monitor
is pugged into the switched AC socket, allowing everythigh to power up at
the flip of a single switch!
What's it cost? Between $40 and $70 (greatly depending on your shopping
ability and whether you purchase a PC clone case, to house external drives),
time AND A LOT OF CAREFUL CHECKING.
This project is placed in the public domain by:
Thomas Nery
and
Products Bynery
14 Chambers Court
Mansfield, Ma. 02048
Make sure you check out ByNeryDemo.zoo. A demonstration/shareware version
of a Amiga 500 hard disk interface, that allows you to add a PC-style
hard disk to your amiga 500 (1000's too) for about $150 (with some shopping).
****************************************************************
** DISCLAIMER **
** **
** NO REPRESENTATIONS OR WARRANTIES ARE MADE WITH RESPECT TO **
** THE ACCURACY, RELIABILITY, PERFORMANCE OR OPERATION OF **
** THIS DOCUMENTION OR THE RESULTING PRODUCT. **
** **
** DO TO THE NATURE OF THIS PROJECT, NEITHER THE AUTHOR NOR **
** Products ByNery CAN BE HELD LIABLE FOR DAMAGES, REAL OR **
** IMPLIED, RESULTING FROM THE CONSTRUCTION, INSTALLATION, **
** OR RELIABILITY OF THIS PROJECT. **
****************************************************************
****************************************************************
** WARNING **
** **
** THIS PROJECT CONSISTS OF MODIFICATIONS TO A POWER SUPPLY. **
** DUE TO THE VOLTAGES AND CURRENTS INVOLVED, APPROPRIATE **
** PRECAUTIONS MUST BE TAKEN. **
** **
** FAILURE TO DO SO MAY RESULT IN BURNS, DEATH OR TOTAL **
** FAILURE OF THE AMIGA 500 AND ALL CONNECTED PERIPHERALS. **
****************************************************************
****************************************************************
** WARNING **
** **
** Make sure you acquire this public domain document from a **
** reliable source. Unfortunately, there are those among **
** us that would like to see your investment go up in smoke. **
** **
** By running the command: arc v PC-XTpwr.arc PC-XTpwr.pic **
** and verifying that the following results are received, **
** you can fairly confident in the integrity of the archive. **
** **
** If you received this file as part of Products ByNery's **
** PcIf registration, rest assurred this is untouched. **
****************************************************************
Name Length Stowage SF Size now Date Time CRC
============ ======== ======== ==== ======== ========= ====== ====
PC-XTpwr.pic 41700 Squeezed 15% 35666 2 Apr 90 5:51p a21a
==== ======== ==== ========
Total 1 41700 15% 35666
The following instructions apply only to PC-XT clone power supplies.
Although PC-AT supplies will work, the color-coding and connectors described
pertain only to the PC-XT.
A PC-XT supply has the following safety features:
* 150 Watt capacity
* Fused input power protection
* Over-Voltage protection
* Over-Current protection
All of the safety features will protect the Amiga in the event of a failure.
This actually save my Amiga once when I accidentally shorted 5 Volts to
Ground during the testing of my PC hard disk interface.
YOU WILL REQUIRE EITHER A VTVM, VOM or DVM to build this project. IF YOU
DON'T UNDERSTAND THESE ACRONYMS THEN THIS PROJECT IS BEYOND YOU. All
voltages must be verified prior to installation. ANY ERRORS WILL RESULT
IN PERMANTENTLY DAMAGING YOUR AMIGA 500! BE CAREFUL!!!
What you will need.
1) A VTVM, VOM or DVM
2) A PC-XT style power supply
3) Your Amiga 500 power supply
4) A Soldering Iron, solder and wire stippers
5) One male and two female, 6 conductor molex-type connectors
This item is available at Radio Shack, part numbers:
Male Connector - Radio Shack part no. 274-226 (1 req'd)
Female Connector - Radio Shack part no. 274-236 (2 req'd)
6) A crimp-on style ring connector
7) 6 inches of 18 gauge multistranded hook-up wire.
On the bottom of the Amiga 500 power supply, as well as in the user's
manual, the following diagram of the Amiga 500's connector appears:
+--\___/--+
| 3 4 |
| 5 |
| 2 1 |
+---------+
where:
pin 1: +5VDC
pin 2: Shield Ground
pin 3: +12VDC
pin 4: Signal Ground
pin 5: -12VDC
With the power supply disconnected from the Amiga, turn the power supply on
and verify these voltages, BEING CAREFUL NOT TO SHORT OUT ANY PINS! All
voltage readings should be performed with the voltmeter's ground cable
connected to the connector's Signal Ground. Record each pin's Voltage.
Once satisfied with the Pin versus Voltage supplied, turn off the power
supply and unplug it from the wall.
Cut The Amiga 500 side of the power cord leaving approximately 10 inches
sticking out of the original power supply. Carefully strip back 1 inch of
cable insulation from each side and then strip each wire, leaving about
1/4 inch of the wire showing.
Crimp then solder onto each wire on the power supply side, a female
connector. Do the same on the side normally attached to the Amiga 500
except use MALE connectors. Each side should have a total of 5 wires with
connectors.
Now insert the female connectors into the Molex-style female connector.
Do the same for the male connectors, BUT MAKE SURE THAT THE WIRE COLORS ON
EACH SIDE OF THE CONNECTOR ARE THE SAME WHEN THE MOLEX-type CONNECTORS
ARE PLUGGED INTO EACH OTHER.
Once completed, verify that there are no shorts between the various wires.
Plug the two MOLEX-style connectors together, plug in the Amiga 500's power
supply and re-verify the voltages. They should be the same as previously
measured.
Once satisfied, your Amiga 500 will operate with the original power supply.
Nice to have a backup, huh?
Now on to the PC-XT power supply. Referring to the picture, PC-XTpwr.pic,
1) Cut the 3, +5VDC power wires on connector J1 and then wire all
three to a single female connector. Label this +5V.
2) Cut the +12VDC power wire on connector J2 and then crimp and
solder it to a female connector. Label this +12V.
3) Cut the -12VDC power wire on connector J2 and then crimp and
solder it to a female connector. Label this -12V.
4) Cut the 4, GND power wires two on J1 and two on J2 and then
wire all four to a single female connector.
5) Connect on end of the multistranded hookup wire to a female
connector and crimp the ring connector on the other end.
Using the Ohmmeter and the previous diagram, determine which pin in the
Amiga 500 power cable MOLEX-type connector carries the +5 volts. Connect
the PC-XT wire labelled +5V to the same slot in the remaining plastic
connector. Repeat this procedure for +12V, -12V and Ground.
The multistranded hoodup wire should be inserted into the slot where
connection will be made with the pin labelled SHIELD GROUND. Remove
one of the screws in the PC-XT power supply, attach the ring connector, and
the put the screw back.
****************************************************************
** WARNING!!!!! **
** **
** IT IS IMPERATIVE THAT THE SHIELD CONNECTOR BE SCREWED **
** SECURLY TO THE PC-XT POWER SUPPLY. FAILURE TO DO SO MAY **
** DAMAGE THE AMIGA 500. **
****************************************************************
Plug the Amiga 500 power cable into the PC-XT power supply, BUT DON'T
ATTACH IT TO THE 500 YET. ALL POWER CONNECTIONS MUST BE VERIFIED!
Plug the PC-XT power supply into a wall outlet, power it on and using the
voltage meter verify that all of the power connections are the same as
previously checked.
Once satisfied, turn off the power supply, unplug the power supply from the
wall, install the power supply in a suitable case and connect to the
Amiga 500. If you wish, you may plug the monitor into the switched AC
connector on the power supply.
IF YOU WERE CAREFUL AND VERIFIED ALL CONNECTIONS, TURNING ON THE PC-XT
power supply should result in the complete powering of your system.
IF YOU FAILED TO CHECK THE VOLTAGES, IT IS LIKELY THAT YOU MADE A MISTAKE
AND TURNING ON THE POWER SUPPLY AT THIS TIME WILL RESULT IN THE COMPLETE
LOSS OF YOUR SYSTEM.