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Help needed 4 calculator's LCD

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apakhira

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Its a long story but here it is:
I had an original CASIO fx-991MS, in which the strip connecting the LCD and mainboard got torn after it had taken a fall. L8r, i had bought another fx-991MS which turned out 2 b fake.
So just as an experiment, i tore off the LCD strip from the mainbard of the fake 1 and tried 2 put it on the real 1. But the adhesive which kept the strip and board 2gether was gone, and now i cudn't connect the LCD 2 any of the boards. The characters show only when i press the strip against the correct metal strips on the board, with my fingers.
I tried a glue-stick (yeah dat was dumb), but it stopped conducting. How do i connect these 2 things. What chemical 2 use? Any help will b appreciated.

Thanx
 
Had a similar situation once with my Digital Diary .. Gave to a Local ELectronics Service Workshop, he fixed it right !! Don't know what he used.. I'l post it as soon as find that out !
 
apakhira said:
Its a long story but here it is:
I had an original CASIO fx-991MS, in which the strip connecting the LCD and mainboard got torn after it had taken a fall. L8r, i had bought another fx-991MS which turned out 2 b fake.
So just as an experiment, i tore off the LCD strip from the mainbard of the fake 1 and tried 2 put it on the real 1. But the adhesive which kept the strip and board 2gether was gone, and now i cudn't connect the LCD 2 any of the boards. The characters show only when i press the strip against the correct metal strips on the board, with my fingers.
I tried a glue-stick (yeah dat was dumb), but it stopped conducting. How do i connect these 2 things. What chemical 2 use? Any help will b appreciated.

Thanx

Here's some info on 'hot glue' .. I've never used it .. so can't tell.. but looks the right kind ..
**broken link removed**
Here's a proj that involves fixing an LCD (into a cabinet)
https://www.disneycorner.com/toddscorner/tivolcd/
 
The TiVo project u posted the link about won't work, coz the lcd used there is a serial-based one, involving power supply wires(2) and 1 data wire, which is easily connected. But mines a parallel connection based lcd, which has around 40-50 wires in the form of strips. I'll post the pic if u want.
And the glue u talked about, well i think it will hav the same problem like the other glues--it will spill into the contacts and make them insulated. I dunno..
 
By "the assembly" do u mean the lcd, ribbon and the ckt board?
4 the record, the carbon(i guess) pathways r intact, only i can't attach the ribbon 2 the board. Even then do i hav 2 replace the whole thing? I mean, there must b a way 2 join the ribbon and board, since they were attached in the 1st place.
 
apakhira said:
By "the assembly" do u mean the lcd, ribbon and the ckt board?
4 the record, the carbon(i guess) pathways r intact, only i can't attach the ribbon 2 the board. Even then do i hav 2 replace the whole thing? I mean, there must b a way 2 join the ribbon and board, since they were attached in the 1st place.

Yes, replace both boards complete with the connecting ribbon, presumably it's joined by a machine at the factory? - I've no idea how it's actually done though?, I've always presumed it's some kind of thermal process?.

But it is a generally crap idea, and EXTREMELY unreliable, it's a major cause of failure in anything that uses them.

Manufacturers provide the complete assembly as a replacement, usually at a stupid price, meaning the items are scrap if out of guarantee!.
 
Nowadays calculators are cheap, don't bother buy a new one, I could understand people bothering about this 10 years ago but not now.
 
I agree. Buy a calculator. It is only $1 at a dollar store.

and this is weird. When I buy an OEM based LCD from SAYAL (electronic store), it has holes in it ready for me to use and assemble, BUT when I look at the LCD's in broken equiptment, they make the connection so stupid, it is almost unrepairable.

In your case, buying a new calculator is well worth it.

and while you are at it, see how many usable components you can desolder form the old calculator before throwing it out. You might run into a crystal and a capacitor.
 
mstechca said:
BUT when I look at the LCD's in broken equiptment, they make the connection so stupid, it is almost unrepairable.

It's simple - it's down to cost - your LCD text module costs more than the entire calculator, the non-repairable ribbon cable is VERY cheap in manufacture.
 
Guess i hav 2 do that. I wish i hadn't opened up the fake 991 w/the hope of making the real 1 work... But speaking of thermal can't i try some DIY thermal experiments on it? hmmm... and btw, the real 991 isn't a $1 equipment.
 
You CAN repair these cables if you really need to. Use conductive silver paint to repair the broken tracks. You may have to remove a protective coating from the top of the track first.
Electrolube and circuitworks make the paint. It used to be sold in car accessory shops for repaing the heater elements on rear window demisters, might still be.

G8RPI.
 
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