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Atari Portfolio LCD Missing Rows Repair

From RetroTechCollection
Atari Portfolio (photo)
An Atari Portfolio open. The LCD and its driver board are in the lid, behind the clear window.

Missing horizontal rows, or bands across the screen, are a well-known fault on the Atari Portfolio. Lewin Edwards, whose notes are quoted on Applefritter, calls missing LCD lines one of the most annoying Portfolio problems to fix, and puts it down to a bad connection between the LCD and its driver board. The cure is to open the lid, release the LCD from the board and reseat it.[1]

The tabs that hold the LCD to its board work-harden: they survive being bent only a couple of times before they break off.[1] Before opening the lid, rule out the contrast setting and the cells.

Symptoms

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  • One or more horizontal lines of the display missing.[1]
  • Horizontal bands across the screen, or a screen of lit pixels.[1]
  • A blank screen with key clicks still audible is more often the contrast setting; see the Atari Portfolio Troubleshooting Guide.

A cracked flat ribbon between the main board and the lid, which also carries the speaker, gives display faults too. One repairer found it cracked on a machine damaged by leaking cells and fitted the display from a donor machine.[2]

Safety

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Take the cells out and unplug the adaptor before opening the lid. The LCD glass is fragile; support it whenever it is free of its board. Heat the window only until it is very warm to hot to the touch, not until the window or the grey bezel starts to distort.[3]

Tools and parts

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  • A hair dryer.[3]
  • A thin blade, such as a knife.[2]
  • Small screwdrivers, including a small flat one for easing the case apart.[4]
  • A new window, Best Electronics CB102207, because a window that has been peeled off seldom lies flat again.[3]

Procedure

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Remove the window

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  1. Warm the clear window over the display with a hair dryer on a medium setting until it is very warm to hot to the touch.[3]
  2. Starting at one corner, peel the window off from one side to the other.[3] Arnaud used a knife blade, starting at the top right corner.[2]

Open the lid

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  1. Remove the two small black screws in the recesses that the window covered.[3][2]
  2. Ease the lid's case apart. It is held by plastic clips;[1] Colin Hunt starts at one of the hinge corners with a small flat screwdriver and works round.[4]

Reseat the LCD

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  1. Unscrew the LCD controller board.[1] Arnaud found the screen held in the case by four screws, one at each corner.[2]
  2. Bend open the metal retaining tabs that hold the LCD onto the driver board, as few times as possible.[1]
  3. Ease the LCD and the board apart.[1]
  4. Reseat the LCD on the board so that it makes good contact along the whole connection.[1]
  5. Close the retaining tabs.[1]
  6. While the lid is open, look at the flat ribbon to the main board for cracks.[2]

Contrast (optional)

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On most Portfolios a slotted screw on the LCD board, seen through a small hole at the left of the bezel near the speaker, sets the contrast. Early bezels have no hole over it. Best Electronics advises making any change to it now, once, before the new window goes on.[3]

Close the lid

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  1. Screw the LCD controller board back in place.
  2. Clip the lid's case back together and refit the two black screws.
  3. Fit the new window.[3]

Testing

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  1. Refit the cells, switch on and check that every row of the display is present.
  2. Adjust the contrast from the keyboard if the display is too light or too dark; see the Atari Portfolio Troubleshooting Guide.
  3. Open and close the lid a few times while the machine is on, to check that the rows stay.
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References

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  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 aladds, reply of 1 August 2006 in the thread "Atari Portfolio", Applefritter forums, quoting Lewin Edwards' Portfolio notes (larwe.com/museum/atariportfolio.html): missing LCD lines caused by the connection between the LCD and its driver board; prise the faceplate off to reveal two screws; open the clipped casing; unscrew the LCD controller; bend open the retaining tabs; the tabs work-harden after a couple of bends. Later posts in the thread report bands of lines and pressing the panel against a row of pins on the board.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Arnaud, "Complete Atari Portfolio disassembling and repairing", Consulting Daylights, 23 April 2019: cracks in the ribbon to the screen and speaker; removing the screen's plastic shield with a knife blade from the top right corner; the two black screws beneath; the four screws at the corners of the screen.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Best Electronics, "Portfolio", best-electronics-ca.com: tech tip on removing the Portfolio window with a hair dryer; the two black screws under the window that hold the outer case to the inner bezel; the contrast adjustment screw seen through a hole at the left of the bezel near the speaker; a peeled window seldom lies flat a second time; replacement window CB102207; the hinge covers as the most common failure.
  4. ↑ 4.0 4.1 Colin Hunt, comment of 14 February 2017 on cosi, "The incomplete Atari Portfolio disassembly guide", Vintage Palmtops, 28 September 2013: two black screws along the hinge edge, then a small flat screwdriver to ease the case apart, starting at a hinge corner.


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