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I've got a ThinkPad X32 that won't launch from just the battery, but will work if the AC adapter (or second battery from dock) is present; After launching the laptop, i can remove the external power source and run it just from the battery.

I've been probing around with my multimeter; I've checked battery terminals when the battery is unpluged and the adapter is plugged in (no difference if it's ON or OFF, always no voltage), four goldpins in the docking port that looked like they're transferring voltage (ON - with charger 16V, with only battery nothing; OFF - with charger 16V, with only battery nothing); Every measurement I did, I replicated on a ThinkPad X31 that can start from the battery just fine, unfortunately, every result was the same.

The issue most certainly isn't because the battery is bad - i've got three of these, and all of these work just fine on a ThinkPad X31.

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  • Have you tried removing battery and AC, then holding power button for 10 seconds?If that doesn't work you could remove the CMOS battery.
    – testeaxeax
    Commented Jul 29, 2017 at 12:27
  • @nullterminatedstring Yup, i've tried this one, unfortunately without any luck. CMOS battery was dead, i've replaced it with the one from X31 because i didn't have a replacement, and besides not being forced to wait 2 minutes on boot screen to let the extended memory test pass (or hack my way through it - Esc and then space :>), there were no difference
    – redsPL
    Commented Jul 29, 2017 at 22:53
  • Have you tried holding the power button for 30 to 60 seconds while the power adapter is unplugged and the battery plugged in to do a reset?Maybe the laptop's battery contacts are oxidized and therefore their resistance could be too high to perform a cold start.
    – testeaxeax
    Commented Jul 30, 2017 at 13:36
  • @nullterminatedstring yup, did that, but longer (some old IBM manual recommended holding power button for 10 seconds 10 times, and last time for 30 seconds). As I'm going to travel in the next week, I've hacked myself a temporary solution: connecting second battery through a cable with goldpin plug on it's end to the ultrabay port allows the laptop to boot, but this will be a veery temporary (and very unsafe :v) solution..
    – redsPL
    Commented Jul 30, 2017 at 15:38

1 Answer 1

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All indicators point to a problem with insufficient voltage at boot time, despite the new battery seeming to have a full charge and exactly the same specifications as the old one.

It would take a workshop to analyze the problem, so here are some possibilities only:

  1. The ThinkPad might be one of these laptops that have a small sealed battery that is not user-accessible, and this battery is dead.

  2. The standard battery has just enough power for booting, and some component is now drawing more power than before. The most likely culprit is the hard disk.

  3. Some connected device is responsible. Try to disconnect all devices before booting.

  4. CMOS battery problem. CMOS plays a larger role with laptops, with ACPI and APM. Once bypassed in certain laptops, problems disappear, as is the case when plugging in AC power.

  5. Mainboard malfunction (hopefully not the case).

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  • #1 nope, i've got three batteries; #2, #3 nope, my HDD is an CF card AND i've tried with just keyboard and battery connected, didn't turn on the LEDs #4 ^ tried without CMOS #5 I've seen some corrosion on the mobo, removed it with acetone and reflowed the solder, no change :< (corroded components were a diode, a capacitor, random µC looking like a regulator. Besides that i've seen some corrosion on the side of PCMCIA µC, that may explain why built-in CF card reader doesn't work)
    – redsPL
    Commented Aug 31, 2017 at 17:23
  • #1 : Some laptops have a small unseen auxiliary battery - not the visible battery, but I wasn't able to find any schematics for the X32. I believe that something must be drawing more power on boot than the visible battery can deliver. A workshop could probably find out what, maybe by pulling out cards or using a voltmeter. I have read about such cases as yours where the cause was never found. If you're thinking of opening it up, see the Hardware Maintenance Manual.
    – harrymc
    Commented Aug 31, 2017 at 20:19
  • welp, i've already opened it up, wrote about the corrosion, didn't you see that part? I'm probably going to open it once again if i will get some free time, because i feel that i didn't check enough things with the voltmeter.
    – redsPL
    Commented Aug 31, 2017 at 22:36
  • The corrosion part is what frightens me here (point 5 above).
    – harrymc
    Commented Sep 1, 2017 at 6:16
  • there weren't THAT much corrosion, there was maybe bout' 2-3mm² overally
    – redsPL
    Commented Sep 1, 2017 at 14:45

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