Image Map Image Map
Page 1 of 4 1234 LastLast
Results 1 to 10 of 32

Thread: Toshiba T3100e Memory Upgrade

  1. #1
    Join Date
    Sep 2010
    Location
    Edinburgh, UK
    Posts
    5

    Default Toshiba T3100e Memory Upgrade

    Hi All,

    Has anyone successfully upgraded the base 1MB to 5MB in a Toshiba T3100e?

    It has 4x 30pin SIMM sockets under the keyboard along with the base 1MB soldered. It should take 5MB in total. I've tried 4x 1MB SIMMs in there (both 70ns and 80ns) but can't get it to recognise them. Running TEST3 makes no difference either, it's just the same as the BIOS setup.

    The part codes from Toshiba for additional RAM were only for 512KB or 2MB SIMMs, perhaps it won't recognise 1MB ones but if someone could confirm before I go looking for some 2MB ones on eBay that would be great.

    The RAM does work - I've tried it in a desktop 286. I don't think it's a fault with the laptop either as I've tried it in another T3100e with the same results.

    Thanks,
    Simon.

  2. #2
    Join Date
    Dec 2005
    Location
    Toronto ON Canada
    Posts
    6,993

    Default

    I tried the same thing with my 3100e with the same lack of success; let me (us) know if you discover anything, please.

  3. #3
    Join Date
    Sep 2010
    Location
    Edinburgh, UK
    Posts
    5

    Default

    Thanks for your reply, at least I know it's not just me . . .

    The only interesting thing I've discovered is that if you go into the BIOS setup screen (by holding down Fn on power up or using test3.exe) if you reset by pressing F5, cursor down to extended memory then cursor left it will start to count backwards from 63.5MB.

    I've tried setting 4MB "manually" here by doing this, saving the changes and rebooting. The setting does stick, it shows up if you go back into the BIOS setup, but it makes no difference to the POST test which still only counts up to 1MB.

    The operating system can see the extra memory but writes to it are very slow and it ultimately crashes when trying to read it back. I'm sure this is not intentional behaviour but both my T3100e machines do it.

  4. #4
    Join Date
    Dec 2005
    Location
    Toronto ON Canada
    Posts
    6,993

    Default

    Well, for the first time since I bought it new a looong time ago, thanks to you my T3100 now has 1408KB extended memory; thanks!

    I tried a few different modules way back when without success, so I assumed that it used some kind of non-standard part and forgot about it. Not many portables have 2 serial ports and a modem so I use it as a simple RS-232 protocol analyzer when I can't be bothered setting up my HP18179A, and I don't really need any extra memory for that.

    But your post got me to dig it out and try a few more modules; although I couldn't find any 1M parts that were recognized, a number of 256K modules did work. No 3-chip modules at all worked, and not all 9-chip versions worked either; these worked:
    Hitachi 50256CP12M
    OKI M41256
    OKI M41256A
    Mitsubishi M5M4256AJ-12

    These didn't:
    NEC D41256-12
    T TMM 41256T-12
    TI TMS41256FML-12

    So presumably there are also 'standard' 1M modules that will work.

    BTW, I think you misread the 512K/2M "part codes"; these refer to "kits" consisting of 2 modules (256K/1M), and references to "slot A" and "slot B" refer to the left and right pair of sockets respectively (2x8 bits=16 bits)

    And FWIW, holding the Fn key during boot does nothing on my system; I have to use TEST3.

    Thanks, and good luck with yours.

    mike
    Last edited by MikeS; September 17th, 2010 at 10:44 PM.

  5. #5
    Join Date
    Sep 2010
    Location
    Edinburgh, UK
    Posts
    5

    Default

    Hi Mike,

    Not sure what I did to help! Your post really helps me though, all my 1MB SIMMs are 3 chip so I have no chance. Did you try any 9 chip 1MB modules? What about non-parity 2 or 8 chip ones?

    So with the 256KB modules that do work, do you have to do anything or does it find them on its own?

    Thanks,
    Simon

  6. #6
    Join Date
    Dec 2005
    Location
    Toronto ON Canada
    Posts
    6,993

    Default

    Quote Originally Posted by ironside View Post
    Hi Mike,

    Not sure what I did to help!
    You inspired me to have another look.
    Your post really helps me though, all my 1MB SIMMs are 3 chip so I have no chance. Did you try any 9 chip 1MB modules? What about non-parity 2 or 8 chip ones?
    I don't have any 2 or 8chip modules; the 9 chip ones that I tried that didn't work:
    TC511000J-10
    TI TMS4C1024DJ-80
    F MB81C1000-80P
    ? CL514512J-06
    ? KM41C1000BJ-8

    There was one with Motorola chips that caused a parity error; unfortunately I only found one. That might mean that it's just bad or that it's actually recognized but the other module isn't.

    More research is needed; I'll have to look through my pile of motherboards of that era to see if I have any other 1MB modules to try.

    So with the 256KB modules that do work, do you have to do anything or does it find them on its own?

    Thanks,
    Simon
    No, the memory test just finds them on its own and the manual also suggests that all you have to do is physically install the 'kits'.

    BTW, FWIW it looks like you can put a single pair or any combination of module pairs in either socket pair.

  7. #7
    Join Date
    Dec 2005
    Location
    Toronto ON Canada
    Posts
    6,993

    Default

    Hello again, Simon:

    I chatted off-list with Chuck(G) (one of the resident experts) about this and we concluded that the reason some 256K modules work and some don't may be that 120ns is too slow for the 12MHz CPU but some manufacturers' parts may still work at a higher than rated speed (the on-board parts are 100ns)

    The 1MB module problem may be something else altogether though; could you check and confirm that like mine yours has *10* memory chips (8 x 4x256K and 2 x 1X1M) on board? That would certainly be an unusual SIMM module.

    I have no idea what that extra 1Mb chip could be for; anybody else have any ideas?

  8. #8
    Join Date
    Sep 2010
    Location
    Edinburgh, UK
    Posts
    5

    Default

    Hi Mike,

    I don't have anything that slow My SIMMs are all 80 or 70ns.
    I've checked the board, I have 10x soldered memory chips too although I can't see what they all are without bending them over.

  9. #9
    Join Date
    Sep 2010
    Location
    Edinburgh, UK
    Posts
    5

    Default

    Unfortunately need to add these SIMMs to the don't work list:

    Toshiba THM91000AS-10 9 chip 1MB SIMM

  10. #10

    Default 5 MB success with a 9-chip SIMMs, hardware modifications to SIMM required.

    Greetings, fellow T3100e users,

    First of all, this applies to at least one manufacturer's 9-chip FPM SIMM with parity. The SIMM in my case was using Mitsubishi M5M41000BJ-8 chips.

    I looked down the T3100e technical manual with detailed description of SIMM connector pinouts. It seems that Toshiba had a custom SIMM made, including presence detect pin modification for SIMM pins 24 (256 KB present in slot) and pin 28 (1 MB present in slot). These have a pull-up in the bus side, so your SIMM has to include a pull-down in, say, pin 28 to tell the T3100e there exists an 1 MB SIMM in the corresponding slot.

    Pin 24 is usually left unconnected, so making 256 KB SIMM to show up poses no problem (just wrap up a short to ground from SIMM pin 24). Making a 1 MB SIMM has a difference. Since pin 28 is normally used to carry parity /CAS to SIMM, something has to be done. I am not an expert in the field of DRAM, but wrapping the /CAS from SIMM pin 2 to the parity DRAM chip's /CAS (where the SIMM pin 28 originally went) works. Now you have /CAS for parity chip, and you can break the connection to release the SIMM pin 28 for our pull-down use. From the T3100e side, pins 24 and 28 show 10 kOhms to supply rails, so dimension the pull-down according to that. I used a bare wire, but I guess 1 k resistors would be functional also.

    So, a quick summary:

    1.
    Break the connection between parity DRAM chip /CAS (in my case it was pin 24) and SIMM pin 28.

    2.
    Connect the parity DRAM chip /CAS to SIMM /CAS (SIMM pin 2). Now the parity chip has the same /CAS as the data chips.

    3.
    Make a pull-down from SIMM pin 28 to ground. I used a bare wire, but e.g. 1 k resistor could be used.

    I attached some images of the process. Having a datasheet of the DRAM chips is advisable. I have no idea whether they are all identical or not. I found the M5M41000BJ-8 datasheet with a quick Googling.

    (PS. I take no responsibility for any damage caused to your T3100e/SIMMs, should something go wrong. Good luck!)
    Attached Images Attached Images

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •