Hardware tinkering

I am wondering if there are folks on here that do any repairs or hardware upgrades to their Jornadas
If so, could you offer some tips and advice for me to do some of that type of tinkering on my 720?
Any help would be appreciated.
Are there any kind of tutorials, diagrams or any other helpful information available that can be shared?
Thanks in advance for any help

I made a disassembly guide a squillion year ago for the 700 series
https://www.hpcfactor.com/support/cesd/200208/disassembling_the_hp_jornada_710_720_and_728

The most common mods are to put a 728 ROM/RAM board in it to up the RAM to 64MB and to re-cell the batteries with modern high capacity Lithium cells. Replacing the CCFL with LED's in the screen is also one that you see done, which makes the screen better and extends the battery life quite a large amount.

Are there any any ideas out to extend the RAM with common parts? I think that every 728-ROM-board today comes with a beautiful working 728 No need to kill it for that.

There is this thread from 2019 to extend the RAM with SAMSUNG chip.

It requires NetBSD, I believe.

https://www.hpcfactor.com/forums/forums/thread-view.asp?tid=18693&start=1

... or Jlime.

Looks as if the ROM changes are really necessary to access if not 128MB but even 32MB.

I hoped for a solution like the one for a Commodore C16: Just solder in the new RAM, wire the top address line and the Kernal instantly recognizes the 64MB RAM without any mod.

Well, I have a blank 720 waiting for all the mods in one run: Linux, display light and RAM

The boards do come up on their own from time to time on ebay .
There was a flash ROM project for the 700 series many years ago. It got to prototype but never commercialised. You had to use a programmer to flash then though, they didn't get a software flash implementation going. If you want to resurrect that with larger RAM offerings, you'd be pretty much everyone's hero.

I saw something about an upgrade ROM for more aplications and memory. Apparently no longer available. If it is, I'd like to try it out.
I have tinkered with desktop PCs in the past and I believe working on the Jornada would be similar except that it would be on a smaller scale. I have a Jornad 720 that is ailing and I would like to make it better.
I feel certain I could diassemble and reassemble the machine but I could sure use some help as far as what to look for or look at to determine what needs to be done to get this machine back to top status.
Thanks in advance to anyone who may have some advice for my attempt at becoming a 720 repairman.

Tom, maybe you could start a repair thread with description and some pics. So we can try to fix it

-stefan

Some more information on Stefan’s site on Jornads 720 memory upgrade.
https://www.sp-net.at/doku.php?id=jornada_j720:memory_upgrade

By reading the info...
It looks like it is the same as with other vintage tech: It is possible to re-solder and replace the ram with bigger chips, add the upper address line and then the new address-space is immediately available.

The difference to similiar projects is that the stupid CE-kernel does not test the available ram, but assumes the amount entered in the boot-loader. So no additional ram for WinCE.

With the new Linux all options are open. There is an entry for the ram-size in the boot-config necessary but that only seems to be for convenience (and maybe time). Else it would be possible to add a ram-prober that counts and probes the available ram with every startup procedure. No fixed entry to care for.