How to fix WF-139?

[sp5it]

Hi. A firnd of mine gave me his 2 generation (4.95V open circiut) WF-139.
I dug through threads, but couldn't find solution except buying new charger
Did someone mod this charger to get proper charging voltage?
Can you point me to this solution?
Thank you, Mike

 

[Black Rose]

I believe the 2nd generation WF-139 with the OCV around 5v is the better of the various generations of the WF-139.

I don't think I have ever read of anyone fixing a WF-139, other than wiring up the side bays to charge 16340 cells.

 

[Armed_Forces]

Before jumping to conclusions, based solely on open circuit voltage, try charging a battery!

Check terminating voltage, no greater than 4.2v and cut-off, so there's no trickle charging.
If you fail either, chuck it and get something that works.