Handspring Visor Memory Upgrade

In August of 2001, I got real gutsy. How, you ask? Well, I decided to take a geek-like plunge, and disassemble my Visor.


For the uninitiated, the “Visor” is a Palm Pilot clone, of sorts. The story goes like this: the three gurus responsible for the PalmOS and Palm Pilot, created their own company (Handspring) and set out to make a better Palm. I believe they did just that. You can read more about it at Handspring.

My first Visor (their flagship PalmOS product) was the Solo, which had 2MB of DRAM. Very small, in today’s large memory PDA machines. Still, for its time, it was great. I managed to keep from hitting the memory ceiling by keeping a streamlined tight ship, so to speak. I only installed the most necessary apps onto my Visor, and kept just a few games.

HandSpring Visor Solo
HandSpring Visor Solo

Nevertheless, it wasn’t long before I crept up to the 2MB limit of my handheld. And then last August, a certain module pushed me over the edge. I bought a VisorPhone, which is a GSM phone module for the Visor. It included the Blazer PalmOS internet browser and some other cool free apps. So I was at an impasse — either buy a new Visor with more memory (the next model up, the Deluxe, contains 8MB), or stop using these modules and their included software.

Obvious choice, right?

But I’m a hacker, dangit! Surely there’s something I can do about my memory dilemma! Well, there was something. With some scavenging on the net for tidbits of wisdom (or recklessness, depending on your persuasion), I dug up some interesting data. A really excellent source of help and discussion is VisorCentral.

parts & tools

There are a few companies out there that will take apart your 2MB Visor and replace the internal DRAM with 8MB DRAM chips, or IC’s (Integrated Circuits) as they’re called. A couple such companies are:

  • STNE Corporation — they do mostly memory upgrades, and replacement color cases for Palm handhelds.
  • GetHighTech — they offer a whole line of replacement internal circuit boards, memory upgrades, and miscellaneous parts.

While these two companies offer great services, the inner hacker in me was determined to give this a shot myself. Plus, being an electrical engineer and just handy enough with a soldering iron to be dangerous, I thought I couldn’t lose. So after some more digging on the internet (thank God for Google!), I found the following crucial information, a sort of cookbook on the guts of the Visor:

1. Here is a list of DRAM chips recommended for upgrades (Note that memory architecture is mostly standard across the manufacturer landscape for both pin-out and functions. This makes the device selection rather easy, as it’s really only a matter of distributor availability.):

  • KM416V4104[ABC]S-L6 (Samsung)
  • uPD42S65165G5-A60 (NEC)
  • HM5165165LTT-6 (Hitachi)
  • MT4LC4M16R6TG-6S (Micron)
  • HY51VS65165CSLTC (Hyundai)
  • TMS465169P (Texas Instruments)

I chose to go with the Micron DRAM, since Avnet (a distributor) had plenty that I could sample (ahh, the fringe benefits of the engineering world!).

2. The next step was to download both the 2MB and 8MB datasheets and determine what was really different between them.

But I found that it wasn’t as “easy” as replacing one chip with another. There’s a significant difference between a 2MB chip and an 8MB chip. Their pin-outs are not alike — close, but not quite. However, Handspring was smart in designing only one set of Visor circuit boards (PCBs) for both the Solo and the Deluxe. With a “jumper” component(s) and the appropriate DRAM chip, a Solo can become a Deluxe during the assembly stage. Therefore, if we know the correct jumper configuration, we can turn our Solo into a Deluxe.

memory board & removed chip

In this case, the “jumper” components are zero ohm surface mount resistors. I removed the jumpers from positions R17, R21, R23, and R26 and put them in the vacant spots R16, R22, R24, and R25. Notice they are positioned in pairs: R16 & R17, R21 & R22, etc. However, the R19/R20 pair is not swapped. Relocating these jumpers allows the Visor to see the 8MB DRAM properly.

Here are two detailed pictures of my Visor internal boards and memory board.

boards, top

Sadly, after all this work, in less than three months, my Visor Solo-turned-Deluxe was dead. In the most inopportune of times, right after a car accident, the Visor and attached VisorPhone would not turn on. Despite fresh batteries and frequent “soft,” “warm,” and “hard” resets, the Visor exhibited strange memory crashes and instability. I concluded that my tampering had finally taken its toll, like so much bad medicine.

“Oh well,” I said. “Easy come, easy go.” Besides, this was the perfect excuse to upgrade to a Platinum!

Full Project Gallery:

12 Replies to “Handspring Visor Memory Upgrade”

  1. Dear Rob
    Recently I found my sister’s visor solo in the garage where it has been sitting for almost 9 years!
    Yet it still works, however with 2mbs, I dont think there were any uses till I saw your website.
    Now I dont have a background in electronics / engineering, so I want to know if it is possible to do the same except with a larger memory? Β Or will that be impossible?

    Thanks
    Jack

    1. Jack, yeah it would be possible to do. I no longer have access to the tools required to remove that SRAM chip and replace it with a new one however. I could put you in touch with a company that could do it for you however. I don’t know how much they would charge off-hand.

  2. Hi Rob,
    I’d like to upgrade my 8 MB Prism to 16 MB. I recall hearing that it uses the same circuitry as the Visor Pro (which is 16 MB, that is, 2 x 8 MB chips), and those are easy to get from eBay. Could I just pluck the memory out of a cheap banged-up Pro and put them into my Prism, or do they need to be purchased (can they be?). I’m good at doing delicate things and not really scared to try, but I have no experience with this sort of thing. I know, the Prism is ancient but I like retro-Tech and am perfectly content with it, except the extra memory would be nice. I have two Prisms, otherwise I would not risk it. I googled for info but your site was about the only useful hit.

    Thanks!
    Dini

    1. Dini, congrats to you for wanting to take this on. Modding stuff is fun! However, I should warn you that if you’ve never soldered before, your memory upgrade project will be a discouraging one to start with.

      The memory chips are — if memory serves (pun intended) — about 48 pins or so. That’s a lot of pins to desolder from a PCB without damaging the board. When I did my upgrade, I had access to what’s called a solder reflow machine. It made the process fairly painless.

      I personally wouldn’t attempt this mod with only a soldering iron.

      1. Hi Rob,
        Thanks for the helpful reply. Yes, I did think this would be a fun project, which was the main motivation. But your comment plus the fact that there is so little info to be found on this (I did find some details on Palm upgrades, some of which were very complex!), makes me agree with you that it’s probably not a good idea to start with. Maybe I’ll find the needed chips and get them if they are cheap, as they should be, and when I retire in ~30 years and have more free time (and hopefully my hands are still steady), I’ll reconsider doing it. At one time there used to be reasonably-priced upgrade services for this exact upgrade, so it is probably very doable.

        Thanks!
        Dini

        1. Yep, very doable indeed — with the right tools. And I agree with you. Paying to have the solder work done is the way to go. Some time ago, someone else such as yourself paid me to have a LCD flat panel connector repaired. I sent it to one of my contract manufacturers to have the work done with their automated solder machines.

          If you are interested, I could help you with that process.

          1. I would definitely be interested except there is an eBay seller who sells Prisms that he upgrades himself — which makes sense, since it is riskier business to have customers send their own as in an upgrade service. He knows the condition of the Visor before he upgrades it. However, he had offered to upgrade mine at a very reasonable cost, so I was just contemplating doing it myself, for the experience and avoiding shipping my Prism. He is very honest (I had good experience with him), so I decided to ask him for the upgrade, in part based on your advice.
            Thanks!
            Dini

  3. After I originally commented I clicked the -Notify me when new comments are added- checkbox and now every time a comment is added I get four emails with the identical comment. Is there any way you may remove me from that service? Thanks!

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