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Thread: Toshiba 1200, bios image & caps values

  1. #1

    Default Toshiba 1200, bios image & caps values

    Hi all,
    I have dug out my Toshiba T1200 in preparation for recapping and cleaning. I have not found much info on cap values and internal batteries on the net so I will post some here for future reference.

    First problems with my machine are dead CMOS and RTC batteries. I mesured them and they both come dead. Gladly none leaked. I did not take these batteries appart, only mesured them and compared to avaiable ones to get cells dimensions. Part numbers and specs:

    1. CMOS: XZ0075P04, TOSHIBA 9001R, 4.8V, it is a bank of 4 1/3AA size NiCd cells, spot welded together, wired using 24AWG wire with JST PH 2mm pitch 2 pole connector, length approx 30cm, unknown capacity
    2. RTC: MEMO POWER Sealed NiCd Battery, 2-5IFT-B 129, 2.4V 50mAh by Yuasa Battery Co., LTD. This is bank of two NiCd cells spot welded together (15,4x5,8mm), connected via 26 AWG wire about 17cm long. It uses the same connector as CMOS one.
    3. Main battery: MODEL NO. PA7491U, DC 7.2V 2200mAh, it seems to be 6 cell series pack. Case glued or ultrasonicly welded. It would be possible to 3D print some holder for 6pack of AA or C NiMH cells to fit.

    P1550496.jpgbattery.jpg

    I have taken out BIOS ROM, it is AM27C256-205DC made by AMD. I have backed up contents and attach it here. Here is pic of ceramic BIOS ROM package and main CPU by OKI, 80C86A-2 - cmos version of Intel 8086
    bios_cpu.jpg

    Caps are from Nichicon and Elna

    List of electrolytic capacitors on PSU Board:
    1. 10uF 25V 85C 2.5mm pitch, x1
    2. 150uF 35V 105C 5mm pitch, x1
    3. 220uF 25V 105C 3.5mm pitch, x1
    4. 470uF 25V 105C 5mm pitch, x3
    5. 1800uF 10V 105C 5mm pitch, x2


    List of electrolytic capacitors on Main Board (pitch of smaller caps based on PSU small cap):
    1. 10uF 25V 85C 2.5mm pitch, x3
    2. 33uF 25V 85C 2.5mm pitch, x2
    3. 4700uF 10V 85C 7.5mm pitch, x1


    Power brick is 12V@2.2A center positive, rated 40W. It seems to have 6.5mm outer diameter and about 3mm inner diameter.
    brick.jpg
    Attached Files Attached Files

  2. Default

    Quote Originally Posted by san View Post
    I have taken out BIOS ROM, it is AM27C256-205DC made by AMD. I have backed up contents and attach it here. Here is pic of ceramic BIOS ROM package and main CPU by OKI, 80C86A-2 - cmos version of Intel 8086
    That's the easy bit. The T1200 ROMs I've never seen successfully dumped are the surface-mounted ones: the display font (IC36) and the keyboard microcontroller (IC2).

  3. #3
    Join Date
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    Default

    Quote Originally Posted by san View Post
    Hi all,
    Welcome to these forums.

    Quote Originally Posted by san View Post
    I have taken out BIOS ROM, it is AM27C256-205DC made by AMD. I have backed up contents and attach it here.
    Thank you.
    I have added the ROM image to the collection at [here].

  4. #4

    Default

    Quote Originally Posted by JohnElliott View Post
    That's the easy bit. The T1200 ROMs I've never seen successfully dumped are the surface-mounted ones: the display font (IC36) and the keyboard microcontroller (IC2).
    Yes, that was easy bit. I did not know that there are other ROM's in this system till today. I can try to backup display font ROM as it is supported by by TL866A programmer. But keyboard uC would be tricky as I don't know how to and would have to jerry-rig some contraption to read it. Also I don't think I will try reading any of this two from my machine as mainboard is in very good condition and I would mangle it trying to lift them off. Should you have defunct/not so presantable mainboard I can give it a try.

    There is also Hard Disk controller board (I saw one on usual auction site) and it has ROM similar to BIOS ROM - it should be easily readable.

    Quote Originally Posted by modem7 View Post
    I have added the ROM image to the collection at [here].
    Thanks, if you can, add a note that it was direct read (D), I was using universal programmer to read this ROM. And there is 019E on ROM sticker.


    Following that I am updating capacitor list:
    Code:
    T1200 Toshiba Cap List
    PSU Board:
    Cap     Voltage Temp    Low ESR Pitch [mm]  Amount
    10uF    25V     85C    no      2.5         1
    150uF   35V     105C   yes     5           1
    220uF   25V     105C   yes     3.5         1
    470uF   25V     105C   yes     5           3
    1800uF  10V     105C   yes     5           2
    
    Main Board (pitch of smaller caps based on PSU smal cap):
    Cap     Voltage Temp    Low ESR Pitch [mm]  Amount
    10uF    25V     85C    no      2,5         3
    33uF    25V     85C    no      2,5         2
    4700uF  10V     85C    yes     7,5         1
    
    Inverter Board Caps                    
    Cap     Voltage Temp    Low ESR Pitch [mm]  Amount
    33uF    25V     85C    no      2,5         1
    470uF   10V     105C   yes     5           2
    
    Screen Board Caps                    
    Cap     Voltage Temp    Low ESR Pitch [mm]  Amount
    10uF    25V     85C    no      2           7
    Inverter Board had nasty surprise for me. Inverter Board.jpg And I was curious why inverter was so loud.
    Both caps leaked and oozed goo over the board. There is some minor discoloration but after good wash with isopropyl alcohol I think it will be ok.

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