This may be old news to many of you but it was not to me. Posting it just in case it helps anyone. I bought the EX-921 Walkman stictly to plug in to my car stereo. I got extra batteries thinking about the long road trips. I bought an external AA battery box on eBay with the thought of installing a unified polarity jack in it and using it with an aftermarket converter to plug in to the car's DC output. When I got it, I was surprised to find that it already had a jack in it! It clearly would not have worked with the Powerstream converter I was considering which has a 3.5mm OD plug. I was able to get a 2.5mm allen wrench through the opening in the housing which gave me the size. An eBay seller who had listed a new-old stock Sony DCC-E345 multi-voltage car battery cord for later model disc players had the forethought to post a photo of the back of the package which was full of info. It listed the diameter of the two interchangeable plugs. The diameter of the 1.5/3 volt plug was 2.38mm. I got it. It works. I'm now battery free. Love it. Now if I can just get the correct remote for it..... Don
I don't look for an AC jack but it's a huge bonus when they have them, some battery compartments are roached out and it helps with troubleshooting. As far as batteries, I just got a big pile of Eneloops and the big adapters, can't wait for some road trips this summer with some of the beasts.
