Realtone SC-60 low battery display problem

[isanchez]

Hi,
I have been working in a Realtone SC-60, trying to put it in working condition. The thing is that it is working fine now, after solding a couple of wires and change a transistor.

To fully finish with it I would like to know if you can help me with this:

The calculator works fine, but it always shows the "low battery status" indicator. This is an "L" in the most left side LED character. I have replaced the rechargable batteries with fresh new ones, and they can be charged using a typical charger connected to the calculator without problem. I know it is not very important but I would like to repair it completely, and I have to confess it is a bit annoying...maybe there is something simple, you can tell me to do...

Thanks in advance.
kind regards and Merry Christmas

Ignacio