A/C cord for Motorola Ranger 700?

[radiodayz]

Hi, I have a Motorola Ranger 700 portable AC/DC tube radio from c. 1957 (I understand there was also a transistor version). It has a jack for an AC cord, but modern adapters/power supplies don't fit. I was playing it on batteries for a while (previous owner supplied it with 10 modern 9v cells bundled together in place of the now-obsolete "B" battery, but I'm too lazy to try to rig up something like that again). Any ideas where I could look for a cord for something this old?

Thanks!