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Repair - Thinkpad R60

Problem

There was a laptop, a venerable Thinkpad R60, from the age just after Lenovo took over IBM and before it managed to screw up their laptop quality by cost-cutting the manufacture.

The laptop gradually suffered some wear and tear. First, the motherboard died. This was solved by buying a stripped-down laptop of the same type, with somewhat inferior specifications, together yielding a functional laptop and a box of spare parts.

Then the left screen hinge gave way - the part on the laptop's base, to which the lid is attached.

A bit later the right hinge failed, this time the part in the laptop lid.

Then the LCD itself died; the rightmost column driver started misbehaving and distorting colors in the rightmost sixth of the screen. Then the fourth driver failed, making a column with distorted colors. Then the rightmost one's deterioration progressed, showing total failure and intermittent flashing until the chip warmed up and settled down with just distorted colors, indicating a progressive bonding failure between the chip and the substrate - a thin flexible plastic foil.

Solution

Left hinge

The hinge was a fairly massive piece of metal. It failed through the bulk of the material, with the failure apparently initiated at the stress concentration point at the sharp edge. No surprise.

The hinge was replaced with a spare from the other laptop. However, it was decided to attempt to braze the failed part together, in order to figure out if it is possible.

The part was reassembled, wrapped in thermal insulation fiber mat, sprinkled with borax as a flux, and heated with a torch. The flux melted partially, but the part itself shown signs of melting at the edges. Why?

Turned out that it was a zinc casting. OOPS.

An attempt to save the day was made; the broken parts were placed together and flame-heated, with an attempt to get them to melt together.

The attempt was partly successful. The epic fail part was that the zinc melted in the bulk of the material, and the metalization on the surface acted as a flexible bag that sagged and deformed while holding the molten metal inside.


broken hinge, detail

broken hinge, detail

Broken hinge, in thermal insulation

Broken hinge, with molten borax flux, partially melted

Broken hinge, with molten borax flux, partially melted

Broken hinge, assembled before brazing attempt

Failed brazing attempt

Failed brazing attempt, shown deformation

Failed brazing attempt, detail

Failed brazing attempt, detail

Failed brazing attempt, detail

Right hinge

The right screen hinge failed inside of the lid. The metal rail, bent from sheetmetal, broke in its thinnest point, also at a sharp edge. (Designers note, avoid sharp edges. Stress concentrates there and cracks initiate readily.)

It was decided to attempt to braze the hinge. The parts were placed together into a pair of vises, finely lined up, coated with a generous amount of tetrafluoroborate-based flux, heated with a flame, and then flame-brazed with silver brazing alloy (L-Ag45Sn: 45% Ag, 27% Cu, 3% Sn, 25% Zn, sol./liq. 640/680 °C, work temp. 670 °C). After washing the flux off with water, the hinge was mechanically tested by bending in hand and by repeated cycling of the rotating element, and found satisfying.


Broken hinge

Broken hinge, assembled

Broken hinge, held in vises

Broken hinge, detail

Broken hinge, added flux

Broken hinge, molten flux

Broken hinge, molten braze

Brazed hinge

Brazed hinge

Brazed hinge

Brazed hinge

LCD failure

The LCD panel failed in this way. Four consecutive pictures illustrating the screen image changes during a short period.


LCD failure

LCD failure

LCD failure

LCD failure

Lid repair

For the replacement of the LCD panel the laptop lid had to be stripped down. Then it was found that the pair of the pairs of metal-in-plastic brass nuts that hold the lid to the hinge, where the mechanical stresses of opening and closing the laptop lid are focused at, were torn out of the material.

Pairs of holes were drilled to the lid in the places where the original nuts were.

Washers were made from copper metal sheet. Standard round washers could not be used as the holes were too close together and the washers would collide. The twin-washers, rectangles with a pair of properly spaced holes, were necessary to spread the clamping force to larger area of the lid. The somewhat flimsy plastic would likely not be able to withstand too many load cycles if the screw heads were directly placed onto it.

Pairs of M3 screws were placed through the holes, with twin-washers on each side. They were secured in place with nylon-ring nuts, which simultaneously secured them from unscrewing and acted as spacers of just the right height.

The lid hinges were then seated on the protruding ends of the bolts and secured in place with nuts.

The work was hampered by attempts to save work by thinking that the bottom side of the laptop does not have to be disassembled, and the hinges can be just slided into the holes in the base hinge holders. This had to be remedied with the laptop partially disassembled and things hanging on cables. Other minor difficulties were encountered with mistakes in the order of reassembly, requiring a few times to disassemble part of just reassembled lid.


Laptop lid, drilled holes

Torn out nuts, twin-washers

Torn out nuts, twin-washers

Bolts in place

Hinge in place

Outside view of hinge holder, cable holder

Outside view of hinge holder, cable holder

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