PPP - Hardware tips

Hardware This and That

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This is a place, where I want to post all sorts of trifles I found out. Some of them might be known ... well, I can't check the whole net for 'cross-wisdoms' ... and after all, this is my site :-).

.Palm modem power problem

.A different screen protection?

.Modify the scroll buttons of your Palm III

.One RS-232 port, two cradles

.The 'DTR cradle drain hack' (by K.C. Lee)

.Finally a chance to repair a broken screen

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Palm modem power problem
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Recently I read on the mail list of a 'dead modem' and I remembered the problem I had with mine. I ordered my Palm modem in the States cause it has no approval in Germany (and thanks to the stupidity of our 'FCC' officials it probably never will!). Right out of the box it didn't work and I recognized one of four screws for holding the case together was missing. I didn't want to go through the sending back and forth USA/Germany, so I looked at it myself. The battery contacts are 'only' pressed onto the modem board inside by a *tightly* closed case. I replaced the missing screw, but before, I opened the modem and 'stretched/bended' the battery compartment springs a bit more (only a bit!!), so they can reach the modem board for sure. You can 'feel' the success by the resistance the springs offer when closing the case again, even when the screws are not completely in. When doing that, take care about the leads going to the piezo speaker located under the board. Reassambling is done best upside down, holding the board against the bottom half of the case.
Actually, that way to connect different parts of a device is very common practise these days, it saves the manufacturer money for expensive work for soldered wires or just as expensive, proper connectors. But it causes also alot of failures when not 100% quality controlled. Siemens had to exchange ten thousands of cordless phones a while ago because of the same problem (for Germans: If you have a Gigaset 900 and the earspeaker goes 'dead' sometimes, call Siemens - or hit the phone gently on a hard surface from time to time!). However, the contacts on the Palm modem printed circuit board are very high quality! So once the modem is properly closed, the contacts shouldn't cause any future trouble.
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A different screen protection?
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No, I don't talk about transparent film, Scotch tape or WriteRight. I want to address the problem of cracked screens after dropping the Palm. I understand that the screen crackes, when I read that someone had dropped it on a tile floor or on concrete. What made me wonder, was a post about someone dropping his Palm on a soft *carpet* and his screen cracked too! I started investigating, how the LCD is fixed in the Palm case and everyone who has opened his Palm once, already knows it: It's not fixed at all!
Sometimes I do damage certification for insurances (a very nice job for a technic freak!), and cellular phones seem to be dropped even more often than Palms :-) So I saw alot of them from inside, and nearly all have a kind of protective, foamy adhesive tape between LCD and case. Why is our beloved Palm with a LCD much more expensive than that of a phone not equipped with a thing like that? The LCD also bumps from *inside* against the case when it has enough room to move. That explains, that even a drop on a carpet can be 'deadly'. And I doubt, that you can fit two hard materials like the plastic of the case (although its not sooo hard ...) and the glass of the LCD good enough to leave zero space between them.
So in the moment I'm searching for the right material to attach/glue to the right places. Good places could be either the very edge of the LCD (on the lines of the touch foil) or the inside edges of the upper half of the case. In my opinion it's only important that the material presses tightly against the LCD; so in case of a drop it can't move or is at least 'slowed down'. Additional it seals the Palm better against dust, at least from the front side. Frankly, I never saw such a 'plain' assembly plastic on glass!!
I know that some of the hard cover manufacturers won't like to hear that, but I guess, if the above is true, no extra case can completely prevent a damage. Of course is still can be usefull in harsh environments.
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Meanwhile I got quite some feedback about that matter and some good proposals for additional materials to 'mold' a kind of additional frame for the LCD. The best among them are hot-glue (the type, that doesn't get 'stone-hard', but stays flexible) and silicon 'stuff', you know the type you use in your bathroom to seal grooves and holes. Well, best you try out your favourite soution ...

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Modify the scroll buttons of your Palm III
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I mentioned already on my Palm III page, that IMO the new scroll buttons are a pain, if you use them for a longer time. I use to read alot on my Palm and after latest 10 minutes my thumbs started hurting from operating the scroll buttons. The problem is, that you have to press them too deep, well I found a pretty easy solution. .
PLEASE MAKE A COMPLETE BACKUP BEFORE YOU START !
It's most likely, that the batteries are out for longer than the backup cap lasts!
. Now take your PIII apart the 'usual way' - if you don't know how that works, please leave it to a good friend who knows, or leave it at all :). You have to lift the main board at least until you can take out the hard buttons.
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Ok now, take the batteries out and take the back cover off. When you have your Palm open in front of you (backside up, RS-232 pointing to you), you have to loosen the main board first on the right side. It's fixed with two little plastic 'grips' on the right. Just lift the board a few millimeter only above these grips. Next you have to press the battery compartment *gently* together, it also holds the main board down (you can see the little 'plastic noses' holding the board). Now you should be able to lift the board already high enough to reach the button rubber and take it out from underneath the board. Don't be surprised, the plastic buttons will probably 'stick' to the contact rubber thing. Your goal is, to get a hold of the scroll button 'bar' (the two buttons are one plastic part).
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What you do is, just cut two tiny platic squares (if you can, cut one square and one circle <g>) and put them in the two holes of the scroll button bar, like on the image above (the white pieces on the right image). I thought about an 'international' resource for the plastic pieces and I found one: An empty TicTac box - you know these little spearmint devils, each having only 2 calories :). Anyway, take off the white cap of the box and cut a little piece from the *longer* side of the part that goes into the transparent half of the TicTac box. Odd, the short side is thinner. To be precise, the plastic pieces I used, were exactly 0.81 mm thick (0.0032 inch). If you cut them the right size, they stick in the holes (very handy for later assembly!). But make sure they are not too big, so they can reach all the way down in their hole.
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Now assemble everything again. Put the buttons back into the case (take care - the scroll buttons have an orientation - the flatter one is the scroll-down button) and put back the rubber contacts. Now fit the main board again - exactly in the reverse order as you took it out. A good trick is, to make sure that the board stays from the beginning on underneath the plastic grips on the left side. Then fit it over the battery compartment and finally snap it onto the plastic grips on the right side (again, all seen from behind!).
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When you did everything right, you'll have very 'reactive' scroll buttons from now on. Before you close the case finally, make sure the buttons are not already pressed without user action - in that case your plastic pieces were too thick. IMO, the 'short action' buttons are no problem at all. For one they are covered by the flip top when the Palm is not is use and even if pressed accidently, they don't cause any action when the device if off. However, reading ebooks in bed is the usual fun again ...
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One RS-232 port, two cradles
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You got also a new Palm V and still kept another Palm? Now you have two cradles and not enough RS-232 ports? Read the following ...
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When the PalmIII came out with it's newly shaped cradle, it was still possible to keep the old PalmPilot cradle and hotsync also the Palm III with it. Agreed, it didn't fit perfect, but it worked to sync both models in one cradle. Not so with the PalmV, its cradle is unique and you must use it, also to recharge the unit. Now, how do you connect two cradles to one RS-232 port? If you don't want to plug-in and unplug the cradles all the time, the obvious solution is one of these mechanical port-switches. But you don't need that, it's much easier!
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All you need is a Y-cable that connects everything together :) ... both cradles with the RS-232 port of your PC (or MAC of course <g>). That's an easy do-it-yourself 'project': You just need one female 9-pin SUB-D plug and 2 male 9-pin SUB-D plugs. Then you connect all pins with the same number, so pin 1 of the female to both pins 1 of the two males, etc, etc. In fact you don't need all the 9 pins, but you never know. Such a Y-cable might come handy for something else one day, and then it's good that you can rely on all pins :). Here's how mine looks like.
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Once you have the cable, just plug in everything. The two cradles in the two male ends and the Y-cable into the RS-232 port, done.
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Now, you might imagine that it works as long as one cradle is empty while the other one is in use, but it's even better! You can keep *both* Palms in their cradles, as long as you don't push both hotsync buttons at the same time. The reason is, that all Palms are using an RS-232 driver that is 'deselectable'. That means, when there's no serial activity, the driver is switched off to preserve power. But at the same time, the output lines of these drivers are going into a high impedance state, in other words, they 'disappear' electronically on the bus (what the Y-cable in fact is). So, as long as the serial port is not opened by some app using it, one Palm is not bothering the other.
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ATTENTION: These RS-232 driver chips are quite robust, but I wouldn't push my luck :). Starting for example hotsync operations simultaniously on both units will definitely cause a signal conflict. Under normal circumstances the driver will survive that procedure, but as I said, please don't push your luck!!! Apart from that, it's absolutely senseless, since the hotsync or any other serial communication will definitely fail. Please take also care, that there's no app or hack that keeps the serial port open. In doubt, or when testing new serial applications, you can always remove the currently unneeded unit, then it's absolutely safe.
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I'm using that construction for quite a while now and it's working great. I can sync and test apps on my old PalmIII for example, while at the same time my Palm V can recharge in its cradle. Oh, in case you care, you could even build a 3-way Y-cable, to connect a PalmPilot, a Palm III and a Palm V cradle :) ... have fun!
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The DTR cradle drain hack
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Eversince the DTR signal on the Palms was a kind of problem. For one, DTR is not implemented according to RS-232 standards regarding its voltage level and additionally it causes a constant power drain when the Palm sits in its cradle connected to a PC. Some hacks - if you can call it a hack - just cut that DTR line in the cradle. For hotsync its not necessary. But an external modem for example might well use that signal, depending on the configuration. So I never picked up that 'brute' solution :).
Now K.C. Lee came up with a fine and still simple solution for that drain problem. Using only one general small signal transistor and a simple resistor, all together for 50 cents, the little circuit not only stops the unwanted power drain when the Palm is off, but also corrects the DTR level to 0V instead of the 3.3V when the Palm is off. But I don't have to explain that all again. K.C. Lee compiled a very nice PDF document: .

DTR Hack.pdf (19kB)
. UPDATE: K.C. Lee's website is obviously gone ... anyone a valid URL??
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Note for European users: If you have a hard time getting a 2N3906 transistor, just use a BC557, BC558, BC559, BC327, BC328 - they are all ok and easier to get in that part of the wold :).
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Finally a chance to repair a broken screen
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You might have been lucky so far, but it can happen and usually it happens quick and unexpected :) ... A broken screen meant automatically paying $100 for Palm's repair service (BTW, not really expensive - look out for graphic LCDs with backlight and digitizer on the free market!). The b/w screen in the Palm III series is a custom type and not available on the free market.
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But now there might be a good chance now for a cheaper repair. Gethightech.com offers various possibilities to get away far below $100. Most cracks after a moderate drop are only affecting the protective glass layer with the digitizer, not the actual LCD module. Gethightech.com offers that glass completely with the digitizer for $45. Unfortunately Palm IIIxe owners are left out, there screen is different and the solution doesn't work. On the pictures below you can see the glass you get from Gethightech.com and a typical broken screen, good for such a repair.
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There's not much to say about the installation process. The glass layer is glued on the LCD module with some thin adhesive around the rim and you can seperate the two parts quite easily, just take your fingernails and some time - adhesive loosens slowly! In fact, Gethightech.com has a nice Step-by-Step page how to do it. Generally I would say, you should know yourself whether you have the skills to take your Palm apart and do the job. If you really have 'two left thumbs', find a friend for the job :). The only 'secret' might be the connector for the 4-pin digitizer flat-cable, I get quite some support mail how to get that loose. The trick is to unlock the connector with the two little black parts left and right of the cable. See the images below.
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Just slide that black 'lock' out (a little screwdriver or good fingernails are the perfect tools) and the cable is loose. Once you have the parts seperated and ready to fit the new glass, take care to clean the LCD as well as the new glass layer with a lint free wipe. You won't be happy with your new screen if you have to look always at the same piece of fluff *between* the two parts where you'll never reach again!
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But Gethightech.com also offers complete, used screens for $60 or $80, depending on the screen condition. And there are much more Palm components, also hard to get ones like empty cases, motherboards etc. etc. I like the idea of having finally a 'part shop' for the Palm, excellent idea and highly missed so far.
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If you're not living in the US, Gethightech.com has alternative website and places to order:

Anyone anywhere except Canada go to The European distributor

If you happen to live in Canada, The Canadian distributor is the right link.
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