removing LCD from plastic case?

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SeeMess
Posts: 2
Joined: Thu Jun 18, 2020 5:10 pm

removing LCD from plastic case?

Post by SeeMess »

Hi all,
I would like to remove the LCD on a keyboard unit with a fading yellow shift key to a new keyboard unit that Michael kindly sent me.
I can remove the glass plate first with no problems. But getting the LCD away from the adhesive tape holding it in is a different matter. I've been advised to try bending the plastic part slowly from the left and right side. When I start to do so, however, the LCD begins to turn grey / black where pressure is coming up from behind and I'm a bit unsure about the prudence of proceeding in this way.
If anyone has additional details or suggestions for how to safely unmount the LCD I'd be grateful.
Many thanks in advance - c.
EM41
Posts: 192
Joined: Mon Mar 30, 2020 12:10 am
Location: Overijssel Netherlands

Re: removing LCD from plastic case?

Post by EM41 »

I have not done this on a DM but generally heating helps to soften the glue on these things.
Rob your wifes/girls hairdryer and heat from below, use moderate heat because LCD's don't like overheating.
Another thing I used once is to put a strip of SMD desoldering steel under it and try to carefully lift it, if it works depends on how much space on the bottom and side is available.
HP41C (2x), HP41CV, HP41CX, DM41X β, DM41X, DM42, HP11C, HP48G, HP97
mcc
Posts: 277
Joined: Fri Jun 23, 2017 5:10 am

Re: removing LCD from plastic case?

Post by mcc »

Hi,

Warning! I haven't done this before but it is a recommended way, to remove for example glued mirrors
from the inside of car front windows:
Move a string of dental floss/silk between the LCD and the plastic case.
Pull the string against the case and not the glass of the LCD.

Good luck!

Cheers!
mcc
DM 42 - SN: 00373, Firmware release v.:3.22. / DMCP 3.24. as compiled by SwissMicros
Thomas_ER
Posts: 192
Joined: Mon Jul 24, 2017 3:19 pm
Location: Germany

Re: removing LCD from plastic case?

Post by Thomas_ER »

sorry for re-opening this thread...

Has anyone had any concrete success in disassembling/removing the LCD from the case?
What tips and tricks help here?

Many thanks in advance!
[ HP48/49/50/42S/WP34/HP Prime/ DM42 (#00185+00318) ]
Thomas_ER
Posts: 192
Joined: Mon Jul 24, 2017 3:19 pm
Location: Germany

Re: removing LCD from plastic case?

Post by Thomas_ER »

Thomas_ER wrote:
Thu Dec 01, 2022 8:12 pm
sorry for re-opening this thread...
Has anyone had any concrete success in disassembling/removing the LCD from the case?
What tips and tricks help here?

Many thanks in advance!
added simple questions:
- how should one remove the display?
from inside of the case, or from "outside", removing the covering glas first?
- what is best for removing, applying head or lower temperatures, like freezer?
- which tools are recommended for removing?

Many thanks in advance!
[ HP48/49/50/42S/WP34/HP Prime/ DM42 (#00185+00318) ]
rprosperi
Posts: 1698
Joined: Mon Apr 24, 2017 7:48 pm
Location: New York

Re: removing LCD from plastic case?

Post by rprosperi »

Some things to try to help make removing the LCD easier:

1. Store the calc case w/LCD somewhere cold (e.g. refrigerator) to lower the temperature of the the whole unit; the adhesive is less sticky when cold.

2. Fish a piece of smooth, strong thin line (e.g. dental floss or strong fishing line) behind the glass and firmly/gently use it to slowly 'cut' the adhesive bond. Depending on the line you use and the angles, you may be able to 'saw' the line back and forth.

3. Combine 1 & 2 if both don't work alone.

Why are you trying to separate the LCD from the case?
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
Thomas_ER
Posts: 192
Joined: Mon Jul 24, 2017 3:19 pm
Location: Germany

Re: removing LCD from plastic case?

Post by Thomas_ER »

rprosperi wrote:
Wed Dec 07, 2022 12:29 am
Some things to try to help make removing the LCD easier:

1. Store the calc case w/LCD somewhere cold (e.g. refrigerator) to lower the temperature of the the whole unit; the adhesive is less sticky when cold.

2. Fish a piece of smooth, strong thin line (e.g. dental floss or strong fishing line) behind the glass and firmly/gently use it to slowly 'cut' the adhesive bond. Depending on the line you use and the angles, you may be able to 'saw' the line back and forth.

3. Combine 1 & 2 if both don't work alone.

Why are you trying to separate the LCD from the case?
Hello Bob,
many thanks for your hints!
why? Michael assumes that the LCD may be drawing too much current
(empty batteries, barely visible offimg image). Maybe replacing the Display next time ...
[ HP48/49/50/42S/WP34/HP Prime/ DM42 (#00185+00318) ]
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