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Blowing dust motes off 41 display - Printable Version

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Blowing dust motes off 41 display - Ángel Martin - 06-21-2012

Folks, I finally got a tall keys machine that may be "the one" for a permanent CL donor. Key response is good, general condition is good, no corrosion, gold bearings on AC connector... so far so good, still not opened so it may be a real stiff inside (happened before) so I keep my fingers crossed.

Main visible issue is a dust speck just below the ALPHA annunciator, more conspicuous than a pimple in a pig´s back. Do you HW gurus have a word of advise on how to get rid of it - hopefully without unsoldering the display, pls.?

Thanks a lot,
ÁM

Edited: 21 June 2012, 10:46 a.m.


Re: Blowing dust motes off 41 display - db (martinez, ca.) - 06-21-2012

I've had spotty luck (pun intended) blowing dust out from between the screen and protective window. You may have to un-solder all the little tabs for the screen and lift it out to get the speck out. Or learn to ignore it. At least you have that option; halfnut screens can't be taken out so easily.


Re: Blowing dust motes off 41 display - Matt Agajanian - 06-21-2012

Thanks for posting this Q. I've wondered about this ever since I got my (forgive me) Palm T|X. Even my previous Palm Zire had the same issue. I've tried tapping the display, blowing very hard, and I even hoped that the glitch was something on the display/touch surface that could be cleared up (pun intended) using an iKlear(R) solvent and cloth.

In any event, thanks for posing the question and answer(s) to solve this enigma wrapped in a riddle.

But, let me ask another Q. Does this dust blip ever work it's way off or out?


Re: Blowing dust motes off 41 display - Diego Diaz - 06-21-2012

Hi,

Although I'd rather prefer the HW solution: i.e. desoldering the display and throughout cleaning; and since you seem to look for a way to avoid handling a solder iron... :-) next best choice in my opinion would be a dry air spray can. Most of'em come with a flex tube to help spotting the required area.

Hope you get your Tall-key CL in perfect fuctional and cosmetic shape soon.

Cheers.

Diego.


Re: Blowing dust motes off 41 display, ****caution**** - Geoff Quickfall - 06-21-2012

Diego has nailed it.

The fullnuts lend themselves quite easily to the LCD removal and subsequent cleaning. The only way to get rid of humidity spots or other moisture staining and the 'pimple on a pigs butt' dust motes.

But try for standard motes the can of dry air. Be careful when using it. A sustained full blast of compressed air from a can is VERY cold! It will cause condensation to occur on both the LCD and the bezel crystal resulting in condensation stains which can only be removed by de-soldering the LCD display.

So experiment with the can by lightly depressing the plunger and not a full depress.

Cheers, Geoff


Re: Blowing dust motes off 41 display, ****caution**** - Ángel Martin - 06-21-2012

Thanks guys, I´ll give it a try using caution and will see how it goes. If worse comes to worst I´d have to take the plunge and desolder-clean-solder.


Re: Blowing dust motes off 41 display, - success - Ángel Martin - 06-23-2012

I´m glad to report success: after a few initial attempts, I finally managed to get the speck off - literally saw it flying away once I blew the air stream in the right direction. It was encroached and resisted a bit but now it´s history :-)

The most important precaution was not to shake the compressed air can, which has the effect of adding some gas (propellent I imagine) added to the stream, with a noticeable coldness involved due to the sudden expansion (my thermodynamics days are long gone, so this could be just nonsense).

There´s still a little imperfection in the display, which ironically appears to be the remainings of condensation rings - formed by the dirt existing there after it dried off. It appears that the previous owner had attempted to blow the dust mote off but failed. It´s much less noticeable, definitely I´ll learn to ignore it as db suggested.

I was also cleaning the keyboard with isopropil alcohol (my usual method for the standard treatment) but I got concerned about the shift yellow lables: I think I noticed some light wear and stopped immediately. Does anybody know whether tallkeys units had different lables more susceptible to get wiped off?

BTW the unit has the screw posts *intact*, surely those nuts on the bottom ones must help - shame HP stopped using them, the precursor of "planned obsolescence" perhaps?

Thanks again,
ÁM

Edited: 23 June 2012, 10:04 a.m.


Re: Blowing dust motes off 41 display, - success - db (martinez, ca.) - 06-23-2012

alcohol is a good cleaner. just be sure to blow off, dry off &/or dilute the residue. alcohol will bleach out overlays and etch your newly clean screen if left to dry in a cool place and it sits for a few hours.


Re: Blowing dust motes off 41 display, - success - Diego Diaz - 06-23-2012

Hi Ángel,

Congrats on your successful display cleaning... :-)

Regarding the KB overlay, please take into account that *very* early machines have a "silkscreened" (painted) overlay, with a 'yellowish' shifted legends.

Cleaning those with isopropyl alcohol is not recomended, use use a lightly wet cloth with a mild neutral soap solution; then use only clear watter to remove any soap residue.

Later models use plastic overlay which is printed in the back (more orange-shifted colour) side therefore it can be safely cleaned with alcohol.

Hope this helps.

Best wishes.

Diego.


Re: Blowing dust motes off 41 display, - success - db (martinez, ca.) - 06-24-2012

Thanks for the heads up Diego. If my tall key unit ever gets dirty; i hope i'm not too senile by then to remember your warning. I hope your knowledge wasn't gained the hard way.


Re: Blowing dust motes off 41 display, - success - Diego Diaz - 06-24-2012

Fortunately not, I learnt this by simple observation as I get my first *very* early HP-41C (1936A... IICR) and noticed that the overlay surface was somehow "shiny" and painted... as it still is... ;-)

Cheers ocean to ocean (from sunny Caribbean to sunny California).

Diego.