Hi all. Trying to narrow down an issue with a Sony WM-FX671 I recently purchased on eBay. Hoping someone can lend some assistance. It came with the original NiCad BC-7DC charger (no battery) and the AA adapter to screw on the end. I ordered an HQRP NiMH gumstick off Amazon. I left the gumstick in the charger for quite some time since it was a NiCad charger and tried it out. The Walkman works fine with the AA plugged in. When I put the gumstick in the Walkman will start up briefly, with an audible whine, and will then shut off. Sometimes the LCD will only start up for second and immediately shut off. The terminals were pretty messy when I got it but I thoroughly cleaned them before I tried it out so that's not it. Also, I tested the gumstick in my MZ-E33 MD player and it works fine. Any ideas on what the issue would be? Fixable? Or am I stuck with the AA adapter on the end? Thanks.
I am Not an expert on Walkmans but as a Discman Resurrectionist I say you have a current bottleneck at gumstick battery. Same thing I have when using 9V-300mAmp adapter on Discmans which require 9v-500mAmp for startup. Check solder connections from gumstick, buy another gumstick (in my experience, one out of five ‘new’ ones are Bad), then solder AA battery to gumstick jacks. But 1.7V AA is not the same as 1.2V gumstick ... This is a case when having a desktop power supply ($30 off eBay) narrows down the problem in a minute.
From what you describe, the problem is not the new gumstick, but somewhere inside the Sony WM-FX671. Maybe the battery contacts are still not perfect, or there is a loose connection, a broken solder joint, etc. Or your gumstick is not fully charged. A modern NiMH gumstick should be around 1.5V once fully charged. Like any other NiMH rechargeable battery (eg. Eneloop, etc.). But you shouldn't charge them with an antique NiCD charger like your BC-7 (I have the same one). They don't turn off when the batteries are charged, which would damage NiMH cells. And the charging current is too low. I calculated around 30 hours of charging time for fully charging a 1450 mAh gumstick with my BC-7, which has an output of 66 mAh. See also here for gumstick charging: http://stereo2go.com/forums/threads/looking-for-a-gumstick-charger-please-help.4873/
