help for a wounded warrior

[ggiglio]

Some years ago (2012) I bought an already old X31 just to have a backup machine. Nevertheless, in spite of its no tender age, it quickly became my workhorse.
It always run flawlessy, but now strange things happen:
it no longer starts when connected to the mains, but all is ok if you switch it on while running on battery, provided the battery is FULLY charged.
Once started you can reconnect the battery charger and use the X31 the usual way, at least till the next switch off.
Did anyone experience such a strange behaviour ?

[ajkula66]

Did anyone experience such a strange behaviour ?

Yes, and more than once.

Defective charging circuit, could be caused by moisture or simply old age. Motherboard swap is the only cure.

Personally, I'd use it "as-is" for as long as it runs.

Your machine, your call.

[ggiglio]

Yes I agree with you, even if this X31 is more than a machine to me, almost an (old) friend...
Anyway, I'll try to find a cheap X30/31 on sale for spare parts (maybe I'm lucky).
Cheers
Ggiglio

[Thinkpad4by3]

Yes I agree with you, even if this X31 is more than a machine to me, almost an (old) friend...
Anyway, I'll try to find a cheap X30/31 on sale for spare parts (maybe I'm lucky).
Cheers
Ggiglio

Shall this be what you are looking for: http://www.ebay.com/itm/Lenovo-IBM-Thin ... 2402786526?

A nice cheap parts machine?

[Trzyzet]

it no longer starts when connected to the mains, but all is ok if you switch it on while running on battery, provided the battery is FULLY charged.
Once started you can reconnect the battery charger and use the X31 the usual way, at least till the next switch off.

Some switching MOSFET in charging circuit or same charging IC is damaged. You should take it to electronics service, it's quite easy to repair for skilled technician.

[ggiglio]

Some switching MOSFET in charging circuit or same charging IC is damaged. You should take it to electronics service, it's quite easy to repair for skilled technician.

nowadays the only drawback is the extremely low commercial value of X31,that makes the repair undoable, unless you are already familiar with fine electronics (and I am) and have at disposal the mobo schematics (and I don't).
Anyway, I'll keep enjoing the little beast till it's spinning

[RealBlackStuff]

X31 Schematics
https://elektrotanya.com/ibm_thinkpad_x ... nload.html
Wait until you see: This file is downloadable free of charge: Get Manual
under the picture, then click on Get Manual.

[ggiglio]

@RBS
thanks (as usual) for showing me where to look for.
As far as I can see figuring out how the charging circuitry works will *not* be an easy task.
But at least I'll end up removing dust from my holy books of electronics