That's why I always start with "I have a motorbike: HaHa.
I never tell them about my old radios. In saying that I can't get the 90 volt battery for my little portable valve thing and still have to identify some wax paper capacitors (and a good earth) before I fire up my old DC mantle radio. I can't find a circuit diagram and can't read the old caps.
I like anything old, except for myself!
If it has to remain portable then you could always try 10 X 9V batteries in series, DC to DC converter with battery, inverter etc....and also measure the caps and/or check for any shorts and their ESR.
...... 
, but the concept works on many levels. 
