Bought a replacement battery from batteries plus and resoldered the new one in(exact same part #) unfortunately it work fine for about 2 days then had the same symptoms as the first, was told there is a circuit that has to be reset to re-enable the replacement. But that being said you might try Comsonics cause JDSU/Acterna/Wavetek/? charged me $550 but they were nice enough to recalibrate it too.
This is CABL.com posting #293400. Tiny Link: cabl.co/mbouq