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Background
In fact, we found this so unbelievable that we wrote 3COM tech support and asked them about it, and got the following response: "Leaving the unit in the cradle keeps the serial port connection open. This could use the battery life quicker than normal. When we mentioned it in a forum, John Haggis saw it and thought, "Well obviously that's wrong" and decided to find out what was really going on. He tracked down the PalmPilot drain, came up with a fix and created the "Fix the PalmPilot Cradle DRAIN!" page. Well this was great! One of our top complaints, cured! Everything was dropped in a mad rush to make his cable. But as we were soldering, we realized that the wiring in the pictures was wrong. (John has since updated the pictures with correct wiring.) After letting John know about it, we thought "well, obviously he tested this and it works" and so we looked closer and realized the offending signal line wasn't connected at all! |
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The PalmPilot's batteries drain because the DSR line on the PalmPilot
is never truly 'disconnected' when the serial port is closed.
Rather than rewrite everything, we direct you to
John's page for more technical details, and
Palm's description
of the serial port (note the details on pin 1).
In our document, we
refer to it as the DSR line (as seen from the PC side,) as
opposed to the GPO line/PalmPilot DTR.
Our theory was John's original miswired mod worked because the DSR line simply isn't used by the PalmPilot<->PC apps, and found after researching that extensively that it's true. Thus the only modification needed is to disconnect the draining signal line. The mod was tested and worked great on the systems and software listed on the right. This drainfix modification has proven compatible with all systems.
UPDATE: It's been several years, and at this
point tens of thousands of people have visited this page, and judging
from the email most of them make the mod, and there have been no problems.
The DSR line definitely isn't used to hotsync!
The list of platforms at the right is only a small subset
of the thousands of systems this mod is working on.
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Platforms that were tested with this modification:
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DISCLAIMER: Even though this is really simple mod, something might go awry. Proceed at your own risk. Conklin Systems is not responsible for any damages that occur as a result of attempting this modification. For best results, read all the instructions before starting
This simple change will take less than a couple of minutes. The easiest place to disconnect the DSR line is on the cradle itself. If you pick up your cradle and flip it over, you'll see that it's a simple affair with two halves that snap together.
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If you have an original Pilot/PalmPilot... PalmPilot cradles are really easy to open. Holding the cradle facing you, put your finger on the front piece of plastic in the bottom of the curve and gently press down. Click! Some units will just slide apart.
Some cradles are stiffer than others, and may not snap apart without a pound or so of pressure. If the cradle doesn't come apart easily, Gently use a small screwdriver to lift the two locking tabs up slightly, and that allows you pull the two pieces apart. turn it over and lift up on the tabs shown in the green circles.
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If you have a Palm III-style cradle... The Palm III cradle has a single screw holding the two halves together. It's pretty small, so try and find a small screwdriver, like a jewler's screwdriver.
Once the screw's been removed, the front of the cradle slides up.
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Note the hot-sync button in this picture (seen from the backside, turned 180 degrees) has a notch in it. That notch slides over a plastic guide, and it has to be aligned with that guide before you snap it back together. (We mention it because it's actually rotated a little here in the pic.) |
The Palm III cradle shown here is marked "Rev 4." Some people described
their Palm III cradle as being more like the PalmPilot cradle on the
left. In either case, the goal is to disconnect the wire that connects
to the cradle's pin marked 2 below.
The wire we want to disconnect connects to the circuit board at point 1. There's a picture of the backside of this farther down. |
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In this PalmPilot cradle closeup you can see what has been changed. The leftmost wire, (Marked "B", yellow in this picture,) is the DSR line, and has been disconnected. Don't rely on it being yellow; what's important is it is the leftmost wire connecting to "A" |
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On this Palm III, the wiring is changed, but the goal is the same
- disconnect the leftmost cradle pin 2. In the close up here,
we've unscrewed the board and flipped it forward so you can clearly
see where the wires attach. The wire 3, orange in this case,
was desoldered from the pad marked 4. On front of the circuit
board this pad was marked "E1."
We don't recommend you unscrew the circuit board as we have here - this is only for illustration purposes. The screws hold on by screwing into the plastic base and it's easy to strip the plastic when you screw it back in. Instead... |
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The easiest thing to do would be to cut it off close to the board with cutters. There's enough extra wire to reattach it later should you ever want to. In the pictures, it's actually been desoldered during the research process. Once you've got it disconnected, give it a twist so it stays away from the board and doesn't accidentally make contact with any other wires.
We actually recommend cutting it off close to the board. The soldering is a little tricky (it's smaller than it looks) if you don't have solid soldering skills. If you do, be sure to use a low-wattage soldering iron (25-30 watts) and only heat it long enough to pull the wire out.
| UPDATE: Some cradles have a glob of caulk/silicone adhesive covering the wires, which can make it a little harder to see the wires. The wire is still the leftmost wire, and the modification is the same, but you'll want to be a little more careful trying to clear away the glue so as to not affect the other wires. |
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And that's it! Just snap it back together, gently put the screw back in if
it's a Palm III, and now you can now safely leave your
PalmPilot resting in the cradle like this, neat and clean. Besides Hotsync testing,
we also tested with Metrowerks remote debugging mode and Haus of Maus's
Mouse-simulator program with no problems. The mod also was tested
with NT RAS server using the PalmPilot's PPP stack. And basically, that's
every program we can think of that makes use of the cradle. From
our email levels, we guesstimate there are several thousand modified
cradles out there in use.
If you use your cradle with an external modem, as opposed to the available serial cable or the clip-on modem, then this mod may not work for you. An external modem may require DSR to be high before it will work. If this is the case for your modem, John's mod might take care of it for you. We haven't actually tested this to see if it is a problem because to be honest, using the cradle with your external modem seems an unlikely combination.
A note about your warranty Best of luck and enjoy your new PalmPilot "throne." We sure are! Finally, everything is in its place. |
Pilot Is Here! |
From Doug Smith, this update:
"I just verified that the cradle does not drain on a Mac. The Mac adapter
cable from 3COM does not even pass the DSR line (pin 6 on the cradle DB9)
through. DTR (pin 4 on the cradle DB9) is not passed through either."
A Conklin Systems tradition.
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"What a great idea!
And, what a great page describing the process. Pictures were wonderful!" -George Ruehling |
"THANK YOU! I'll make the "wire disconnect" modification today. (I know this is
at my own risk.) Not being able to use the cradle as a storage stand was a
real disappointment.
You and John have performed a real public service to PP users. Hope 3Com fixes
this eventually."
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"I actually left my new Palm III in the cradle for a couple of days with
about 25% power left in the batteries. Much to my dismay when I fired it
up all my data was gone and it reverted back to the factory
configuration. Luckily I had done a hotsync to save the data. I've been
burned by lost data to many times before. I was scratching my head
wondering what happened and then chalked it up to bad batteries. Now I
know I'm not crazy. Thanks for your well laid out web page. You guys
should do the technical documentation for 3Com. Thanks"
-Mike Tetreault |
"PalmPilot Pro user here, just wondering, after reading your amazingly
great article, WHY 3COM created that cable?!?!?!"
-ALEX TUTUSAUS |
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"You are a genius! The fix worked perfectly on my Palm IIIe's Cradle. I'm
only 13 years old so if I can do it anyone can!" -Reese Broody |
For Palm/Pilot owners, we also chronicle the legends of PalmPilots on the popular Pilot Was Here! Guaranteed to please!
We also have a completely unrelated automotive history site that's quite popular, the Conklin Systems Firebird pages which covers the development of the turbine powered car in America in the 50's.
Conklin Systems itself provides high-end consulting services to the computer industry, helping other software/hardware companies with the business of being software/hardware companies. We provide assistance with marketing, management, and product development.
A lot of people have tried this mod, tested new configurations, and given us invaluable feedback on how the instructions could be improved. We'd like to say a big thanks and forgive us if we missed you.
People who took the time to make the world a better place:
Jasen Minton (our first NT report), Dave Borr (Power consumption), David M. Longanbach, David H. Alberts and Scott Fox (alternate mods), Abused Sean and Jonathan Alexander (Palm III alerts), Jim Thompson (Newton keyboard), Neil Goodman (pre-PalmPilot cradle news), Andy Dufek & Paul Carver (Hey what about this glue?) Juan P. Hernandez (TailLight), Erik Bunn (Silicon Graphics test), David Want (proofing), Moe Rubenzahl (first Mac test), Jack Repenning (how to properly open a cradle!), Simon Burge (DECstation test)
One of our top complaints with the otherwise spiffy PalmPilot is
a small design error that drains the PalmPilot's batteries
anytime the PalmPilot is sitting in the cradle. The PalmPilot cradle, sitting
there on your desktop, is the obvious place to set your pilot, and in
fact many advertisements feature the PalmPilot shown in its cradle. But
in practice, you can't do that, lest you drain your batteries.
