Atari Portfolio General Maintenance

Atari Portfolio with a 32 KB Atari memory card

Routine care of the Atari Portfolio centres on its AA cells and mains adaptor, the lithium cells in its memory cards, the display window, the keyboard and the hinges. Fault diagnosis is on the Atari Portfolio Troubleshooting Guide. The board's capacitors are covered on the Atari Portfolio Capacitor Replacement Guide, and Atari's own hardware description is the Atari Portfolio Technical Reference Guide.

Batteries and power

The Portfolio runs from three AA cells. A switching regulator steps their voltage up to 5 V, and the regulator can be switched off. BJ Gleason's 1992 Portfolio FAQ gives about 100 hours from a set of cells.

Cells

• Remove the cells before storing the machine.
• While the cells are out the system RAM, and with it drive C:, is kept alive by an internal capacitor. Atari calls this NO POWER mode and says the voltage on the RAM supply line (VRAM) decays while it lasts. Atari gives no hold time and no value for the capacitor, so change the cells quickly and copy anything on C: to a memory card first.
• The cold reset contact is the small metal tab under the battery cover. Pressing it clears drive C:, so take care when cleaning the compartment.

Rechargeable cells

NiCd and NiMH cells work, but their voltage falls away much more steeply at the end of discharge than an alkaline cell's, so the LOW BATTERY warning may not appear before the machine stops. Keep anything important on a memory card when using them.

Mains adaptor

The adaptor is 6 V DC, 300 mA, centre positive. atari-computermuseum.de gives Atari's HPC-402 as an example; Best Electronics lists the US 110 V supply as HPC-401 (C103599-001) and a separate German 220 V supply. The adaptor feeds the VEXT line, which goes straight to the jack socket. With cells and an adaptor both connected, the Portfolio runs from whichever is at the higher voltage.

Run from the adaptor whenever the serial or parallel interface is attached. Atari recommends an external supply wherever practical with a peripheral fitted, and the FAQ says the interfaces draw about as much power as the Portfolio itself.

Leaked cells

The cells are alkaline, so the residue is alkaline. See Battery Explosion, Capacitor or Corrosion Damage for the general method.

1. Remove the cells.
2. Neutralise the residue on the contacts with white vinegar on a cotton bud, then clean with isopropyl alcohol.
3. Use a fibreglass pen on heavier corrosion to get back to clean metal.
4. Open the case and inspect the small power board. It carries the power jack, the battery contact and the reset button, and joins the main board through a white ribbon cable. Check that cable and the board's traces for corrosion.

Memory cards

Card cells

Atari's RAM cards are static RAM, and each card has its own lithium back-up cell, which Atari says keeps the data on a card outside the machine "for a year or more". The cell is a CR2016. The 1992 FAQ puts its life at about a year and suggests writing the replacement date on the card. A card that loses its contents whenever it is taken out of the machine has a flat cell; the computer is not at fault.

Changing a card cell without losing data

1. Insert the card and switch the Portfolio on. The Portfolio powers the card through the slot while its cell is out.
2. Remove the old cell and fit the new one with the machine still on.
3. Press a key every so often. If the Portfolio powers itself down part-way through, the card's contents are lost. Atari puts the keyboard time-out at between 128 and 256 seconds.

Card contacts

Clean the card's gold contacts with isopropyl alcohol on a lint-free cloth and blow the slot out with compressed air. Use only Portfolio cards: Atari warns that similar-looking cards from other makers may damage both the card and the machine, and the FAQ names the HP palmtop, Poqet and Sharp PC-3000 cards as incompatible.

Display

The display is a 240 × 64 pixel super-twist LCD, driven by a graphics LCD controller with its own screen RAM and character-set ROM. Contrast is held in a control register and set from the keyboard.

Window

The clear plastic window over the LCD is stuck to the inner bezel. Clean it with a soft cloth and a mild glass cleaner; solvents such as acetone will craze it. Best Electronics sells new windows (CB102207) and gives this method for changing one:

1. Warm the old window with a hair dryer on a medium setting until it is very warm to the touch, but not so hot that the window or bezel starts to distort.
2. Peel it off from one corner, working across.
3. Set the contrast trimmer (below) before fitting the new window, because the window covers it.
4. Fit the new window.

Contrast trimmer

Under the window are two small black screws that hold the outer case to the inner bezel, and on most machines a third, silver slotted screw head through a small hole at the left of the bezel near the speaker. That is the LCD contrast trimmer on the LCD board. Turning it darkens the characters and the background together. Early inner bezels have no hole over the trimmer. Try the keyboard contrast setting before touching it.

Keyboard

The keyboard is a 63-key switch matrix, scanned by the custom ASIC as an eight-by-eight matrix; the BIOS translates its scan codes into PC ones. Under the metal shield is a keyboard foil, then the rubber key mat, then the keys.

• Remove the cells before cleaning.
• Blow debris from between the keys with compressed air and wipe the key tops with a cloth lightly dampened with isopropyl alcohol.
• For anything more, take the keyboard half apart (below). Let the foil and mat dry completely before reassembly.

Hinges

Best Electronics, which reconditions Portfolios, calls cracked hinge covers the most common failure on old machines. There are four: the left and right roll-pin covers on the inner bezel and the two on the top case. Once they crack, the open display either closes by itself or falls back flat. The hinges are held by four roll pins. Best sells a new case set (CB103119).

Disassembly

Portfolio main board C103911-001 out of the case, with the small power board (jack, battery contact and reset button) on its white ribbon cable at the bottom left

Keyboard half

1. Remove the cells and any memory card.
2. Peel off the rubber feet on the underside and remove the two black screws beneath them.
3. Remove the two small black screws at the expansion connector.
4. Open the case carefully.
5. Remove the four silver screws holding the main board. Release the display ribbon from its brown connector by sliding the connector's moving part open with a small screwdriver.
6. Unplug the green keyboard ribbon cable and lift the main board away.
7. Remove the silver screws from the metal shield, including those holding the three black cables and the metal plate. Mark the direction of each black cable before removing anything.
8. Lift off the shield to reach the keyboard foil, the rubber mat and the keys.

Display half

1. Remove the window as above.
2. Remove the two black screws under it.
3. Ease the case apart with a small flat screwdriver, starting at one of the hinge corners. The case is held by plastic clips.
4. Remove the four screws at the corners that hold the LCD to the case.

The ribbon between the main board and the display half also carries the speaker. One repairer found it cracked on a machine that had also suffered battery leakage, and fitted the screen from a donor machine instead of bridging the cracked tracks.

Storage

• Take out the AA cells. Drive C: will not survive long without them.
• Store memory cards separately, with the date their cells were last changed.
• Keep the machine somewhere cool and dry, out of direct sunlight.

Related pages

• Atari Portfolio
• Atari Portfolio Troubleshooting Guide
• Atari Portfolio Capacitor Replacement Guide
• Atari Portfolio Technical Reference Guide
• Battery Explosion, Capacitor or Corrosion Damage
• Recommended Tools