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Making IR optics.

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Noitoen:
Looks like a standard graphic display to me. You could probably change it without hassle.

S. Heslop:

--- Quote from: Noitoen on July 06, 2016, 08:53:17 AM ---Looks like a standard graphic display to me. You could probably change it without hassle.

--- End quote ---

If I was smarter I could probably look at the data sheet for it and try figure out if theres a cheaper display out there that would accept the same inputs (I still don't know much about electronic engineering!), but i've got a few things to try first.

I've been wanting to get a temperature controlled soldering iron for a bit now, and this gives me an excuse to get one. Then I can try maybe melting the glue back together with that and a bit of silicon rubber to stop the iron directly contacting the plastic.

I'm fairly sure, after googling about a bit, that it's ACF bonded. Most ACF bonding stuff i've found is videos of Chinese/ Romanian people trying to make a living refurbishing various broken LCD screens, and pdfs from companies selling the glue. Yet to find a firm in the UK that looks like it'd accept a one-off order, but looking at the methods used it just seems to be a hot bar constructed similar to a solder gun tip (but wide) and a cylinder to apply a specific pressure. The companies that make the tape supply information on the recommended pressures and temperatures. It could be in the realm of something I could do myself if I can find a supplier for small amounts of the flex and tape.

Either way i'm skint at the moment since some things came up. So i'm sitting on it for now.

Joules:
I've repaired a number of LCD connectors by cleaning (Isopropanol, fibre glass brush) all the gunk off the cable and connector and make my own pressure pad/gasket.   Using two sheets of glass or polished metal use shim to space them apart.  Apply Vaseline or cling film as release and squeeze a layer of bath sealant, leave till set.  Using a scalpel make a strip to apply pressure to the connection when you re assemble the display or cable connector.  You can then nudge the cable position till your display comes back to full life.  If you made plenty of gasket and the connection is near the edge of the board, a bulldog clip can apply temporary pressure.  Once the right position is found use the rear of the scalpel blade to scratch aligment lines on the cable and PCB where it won't be damaged.

S. Heslop:

--- Quote from: Joules on July 07, 2016, 01:40:09 AM ---I've repaired a number of LCD connectors by cleaning (Isopropanol, fibre glass brush) all the gunk off the cable and connector and make my own pressure pad/gasket.   Using two sheets of glass or polished metal use shim to space them apart.  Apply Vaseline or cling film as release and squeeze a layer of bath sealant, leave till set.  Using a scalpel make a strip to apply pressure to the connection when you re assemble the display or cable connector.  You can then nudge the cable position till your display comes back to full life.  If you made plenty of gasket and the connection is near the edge of the board, a bulldog clip can apply temporary pressure.  Once the right position is found use the rear of the scalpel blade to scratch aligment lines on the cable and PCB where it won't be damaged.

--- End quote ---

This display uses a ribbon cable for the rows and a zebra connector for the columns so there's no easy way to get at the ribbon cable under the display's can when it's all assembled. It also comes with its own rubber lump to put pressure on the cable.

I tried the lump of silicon rubber with a soldering iron to try get the connector to stick again and it seemed to be working, till I slipped and poked a hole in the ribbon cable. I've now got enough rows working again that I can read the numbers and navigate the menus, albeit with a bit of guessing, so i'm leaving it like this before I wreck it further. But there's yet another problem; sometimes the whole thing becomes unresponsive. Not sure at all what could be causing that, but perhaps i'm somewhat under-volting it. The back says 12-30 volts which suggests it could take all the way up to 30 volts input. But of course i'm a bit hesitant to just start sending more volts in.

S. Heslop:
I can't help myself. I saw a totally broken one for sale and bought it to try help solve the few remaining mysteries.


The brass part is the system for lowering a calibration weight.


This arrangement is starting to get familiar. It's a much less panic inducing way of constructing it though than it being machined from solid.


The fault with this balance was that this part had snapped. It's a double flexure to connect the voice coil lever beam to the main parallelogram (i'm making these names up).


This is the inside of the voice coil. There's a pair of fairly strong opposing magnets that go in the middle of it. The lever beam floats on a pair of reasonably stout flexures and is electrically connected by two extremely thin flat wires. The optical position sensor is just a slot cut in a metal bar in between a transmitter and reciever.


Measuring the resistance of the coil. I'm not sure if this gives me any really useful information but it seemed like a clever thing to do!


The circuit has a bunch of op amps on it, a precision voltage reference in the middle, what I assume to be some sort of thermocouple, and this unidentified blob. It was hidden under an aluminium can filled with rubber, and it's quite well isolated. For thermal stability I assume. Might try dissolving that resin off to see whats underneath.


I need to take a closer look at the main board before I can really take a guess at what does what, but i'm leaving that for now. For the record I have no idea what i'm doing when it comes to electronics and i'm mostly just googling the chip numbers.

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