Vintage Toshiba T1200XE - trying to fix (CMOS battery problem?)

Discussion in 'Toshiba' started by Aceri, Dec 12, 2018.

  1. Aceri

    Aceri Newbie

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    I got this vintage machine some time ago.

    First it powered on and booted to DOS, after shutting down it no longer booted. Red led was flashing and that was it.

    I opened it and discovered that "resume battery" or whatever it is called (AAA looking batteries wrapped in yellow plastic) was in really bad shape, had leaked. Power supply board was also smelling weird and indeed it seemed like capacitors had leaked (no visible damage on top of them though). I replaced them as well as on 2J182 mosfet (with some help from another forum).

    Main battery was of course also dead but I also measured that CMOS battery doesn't work either. I got the machine to the point where it would power on and beep once then turn off. Hard disk would spin up and LCD was powered on.

    After searching for more tips I just decided to remove the CMOS battery entirely (it is soldered on motherboard, it's not CR2032 coin cell battery)

    Curreny situtation is: If charger has been disconnected for a while, the machine will power on and beep with message on screen which compains about bad checksum and bad battery, it tells me to check system and then press any key. If I press a key it will repeat this same screen and when I press a key second time the machine will power off and the red led will start blinking. I can try again but now it will power on and shut down immediately after a beep, I think memory test is quickly flashing on screen. If I leave the charger unplugged I can then get to the CMOS complaining screen again.

    Does this machine absolutely require working CMOS battery to be able to boot?

    EDIT: I installed normal 1.5v AAA battery as bios battery, original is apparently 2.4v or atleast one website sells battefy for this model saying it is 2.4v. However, this battery sseems to do the job as the computer only complained about bad checksum and not battery. After installi the battery it does only the second thing mentioned before in this, machine powers on, beeps and the shuts down and red led starts blinking.

    I don't know if this machine absoabsolutely needs the sub battery to be installed, at the moment there isn't.
    Last edited: Dec 13, 2018
  2. Riley Martin

    Riley Martin Notebook Consultant

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    I cant see what youre dealing with firsthand, but Ive taken a mobo, wrapped it in tinfoil, put it in a preheated oven at like 120deg F (I forget the temp, you can look it up). Leave it in oven for a bit, yank the CMOS out after heat weakens soldering, and replace with new. When u replace w/ new do same step, oven, clean tin foil to prevent contamination, but also have a Rock, or Weight of some sort you can place on top of new battery when reheating to adhere (kinda like youd do with thermal paste, but a little hotter if your mobo can handle some heat). Bush fix

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