I got a broken T60/61 9-cell battery, which caused T60 notebook charging indicator to flash rapidly. Also the IBM battery management showed that the battery charge was 0 %, and it was unable to charge up.
The battery cover was disassembled (against all warning texts on the battery), and the cells were measured (in place). They were all OK, Voltage was about 4.05 V in each (which means ~80 % charge). However the voltage will not come to the battery external connectors (see picture below).
I have researched the problem, but couldn't find similar cases. It is common, that some T60/61 (including 42T4511) batteries have died at the same way, but nobody have tried to fix the problem. They just bought a new battery.
So, let me be the first who is writing about the fixing of the problem. I have already another battery to my T60, so the dead battery would end up to recycling anyway. I can take this project as a hobby… like all my Thinkpads.
Firstly I compared the both batteries:
- First day of use: 03/2008 (42T4511 - dead) // 03/2009 (42T4619 - working)
- Charging cycles 148 // 193
- Capacity left ~50% (both)
For me it looks like there could be a blown fuse symptom. There is a white 3x5 mm component, reading SEFUSE D6Y7XA, which seems to be broken. The multimeter showed an infinite resistance over the fuse.
Here is a picture describing the problem (click to enlarge):
And here is a full resolution picture to see more details (3 Mb size)
If the fuse causes the problem, it sure would be reasonable to change it. But is that SEFUSE D6Y7XA some special type of fuse, because no datasheets can be found?
Could someone recommend another similar type of fuse for me to buy and try if it helps.