Compaq Portable (Original)

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Revision as of 19:08, 13 July 2022 by Amminadabz (talk | contribs) (Added C401 warning)
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For more information, see this article's corresponding Wikipedia page: Compaq Portable.
This device is in the WorkNeeded:OriginalParts category because it was flagged as missing information on the original parts. It may have replacement parts listed but those cannot be assumed to be identical to the originals. If you have a list of the original parts, please feel free to add them by copying the relevant table from EditorsToolbox:Tables
This device is in the WorkNeeded:General category because it was flagged as missing general information about the device. The information may be incomplete, using default text, or inaccurate and should be verified with external sources if possible. If you can add or correct information on this page, please feel free to edit it and do so.
Compaq Portable
Preliminary Information
Release Year 1983
Leak Risk Low
Batteries None
Mounting Technology Through Hole, Sockets
Capacitor Types Aluminum Electrolytic, Others
Destructive Entry No
CRT Guides
General Information · Repair Cautions

The Compaq portable was one of the first of the IBM PC clones. It came in a "luggable" form factor, with a built in monitor, dual 5.25" floppy drives, and internally connected detachable keyboard.

Known Issues

Unresponsive to Keyboard Input

Causes

  • The Portable made use of a "foam and foil" key switch design, a type of capacitive switch wherein the key presses a plastic-foam-foil sandwich onto a set of contacts. Over time, this foam degrades to the point of disintegrating at the touch.

Solutions

  • New foam and foil pads can be fabricated by hand (see here) or purchased (here) when in stock.

Disassembly Notes

Disassembly is also covered in the official service manual, linked at the bottom.

  • The outermost case has two removable plastic panels on the top and bottom They are attached by clips on the back (the side with the handle). I recommend prying outward at each clip with a plastic prying tool, working from one side to another, using clips or other tools to hold previous clips open as needed.
  • Under the plastic panels is a metal inner case. Most all inner case panels can be removed by loosening the flathead screws and a few nuts (these can be removed, but do not need to be removed to remove the panels). On the top, there are panels covering the three main sections of the inner case: the ISA slots, Floppy drives, and monitor/PSU section.
  • The ISA cards are fairly standard if you are familiar with IBM clones. They are screwed in to the case on the external facing side, and fit into plastic grooves on the opposite internal side.
  • The floppy drives are screwed in on the top and bottom of the machine. To remove them, you should first remove all of the ISA cards, unscrew the drives, and pull them back towards the handle side to be lifted out from the card area. The front plastic drive covers and latches can remain attached during removal. There is an additional metal cage screwed onto the drives, which can be removed to access the drive heads for cleaning.
  • The CRT control board is attached by one screw and three plastic standoffs. To remove it, remove the screw and pull the board upward to remove the plastic standoffs from their slots, removing the CRT cap connector and other cables as you go. I found it necessary to remove a zip tie retaining one of the cables attached to the board. This is very difficult. Feel free to curse.
  • The motherboard power connector and motherboard keyboard connector are accessible from the bottom of the machine. After removing the outer plastic panel, remove the small metal panel by loosening the screws, as you have done on the top of the machine.
  • The keyboard is held together with many, many screws. Keep track of which type of screw goes where. In the top right corner there is a voltage regulator which produces a significant amount of heat during operation. This heat is normally dissipated through the metal metal key assembly with thermal paste. For testing with this assembly removed, you can stack coins on top of the regulator. This is much less effective at dissipating the heat, but is better than nothing.
    • Four small plastic clips retain the hard plastic backing of each foam and foil pad. When replacing these, the backing can be pressed into the clips with a fingernail or pointed object.

Original Parts

CRT Control Board

TCI-A1S (AIS?) 94V-0. Also labeled 204-1265B. Located within the monitor assembly. NOT the video card.

This table only contains the Electrolytics at the moment. There are also other types on this board.

IMPORTANT: C401 may be installed backwards from the silkscreen; the silkscreen is wrong in this case. With the board oriented with C401 at the top, the negative lead should be on the left.

Capacitor Specifications and Footprint Information
RefDes Qty Capacitance Voltage Mount Diameter/Size Height Lead Spacing Temp Type Brand Series
C311, C312, C313 3 47 µF 25 V Through-hole 6.4mm 105 °C Aluminum Electrolytic Elna
C132, C316 2 470 µF 16 V Through-hole 10.2 mm 105 Aluminum Electrolytic Elna
C122, C401 2 22 µF 100 V Through-hole 10.1 mm 13.1 mm 105 Aluminum Electrolytic Maron
C123, C124 2 220 µF 25 V Through-hole 10.1 mm 105 Aluminum Electrolytic Nichicon
C304 1 47 µF 16 V Through-hole 6.4 mm 10.8 mm -40 to +85 Aluminum Electrolytic Unknown, purpleish
C309 1 1 µF 50 V Through-hole (axial, negative pin to hole just right of where it looks like it should be) 5.1 mm Axial, bent for vertical orientation 85 Aluminum Electrolytic Maron
C307, C402 2 10 µF 25 V Through-hole 5.2 mm 11.2 mm 105 Aluminum Electrolytic Maron
C308 1 1 µF 50 V Through-hole 5.1 mm 105 Aluminum Electrolytic Elna
C317 1 470 µF 25 V Through-hole 13.2 mm 105 Aluminum Electrolytic Maron
C310 1 4.7 µF 25 V Through-hole 5.1 mm 105 Aluminum Electrolytic Maron
C113 1 47 µF 25 V Through-hole 6.4 mm 105 Aluminum Electrolytic Maron
CX117 1 6.8 µF, nonpolar 50 V Through-hole 18.1 mm [not marked] Aluminum Electrolytic Nichicon
C108 1 33 µF 16 V Through-hole 5.1 mm 105 Aluminum Electrolytic Maron
C133 1 100 µF 16 V Through-hole 8.1 mm 105 Aluminum Electrolytic Elna
C131 1 220 µF 10 V Through-hole 8.1 mm 105 Aluminum Electrolytic Elna
C134 1 1 µF 250 V Through-hole 8.1 mm 85 Aluminum Electrolytic Nichicon

Replacement Parts

CRT Control Board

Capacitors
RefDes Qty Compatible Part Number Order Links
Digikey

If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.

Kits

Related Links

References

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