Radio Help electronics

below are images of a radio (Motorola) I am selling on eBay for $25 I get lots of views but never a buyer this is probably because being honest I state I don’t know if it works or not, therefore I thought I would test it, but it has 3 Black wires on the back and I assume the body of the radio is the ground and the single black wire is the power and the two wires next to the capacitor ?, is for speaker connections, using the photos attached can someone who has electronics expertise please tell me how to connect this to test it.


I found a resource on the 'net that provided me with a circuit diagram that enabled me to convert a negative earth radio to a positive earth ('62 model). I would enter the brand and model number into your browser and see if you can get some assistance this way. The two black wires adjacent to the power transistor look like speaker wires - often one of these will have a white trace running its length (conventionally negative to speaker). The other is the business end 12 volt (positive or negative). How old is the radio? Paul

it has a switch to go from Neg to Pos and I believe its a 60’s or 70’s radio.
I just wish to sell this radio at a fair and cheap price as I have no use for it and throwing it in the trash seems such a waste.
Extra pics may help.

My usual source (KevinChant) does not have a circuit diagram for this one. I would be inclined to:
fit a small fuse in line the single black line - say 0.5 amps to 1 amp
connect a 12v battery positive to the single black lead (polarity switch to negative earth)
earth/frame to battery negaive
connect a small speaker - either way around
connect an aerial

And see what happens. If it works its worth more than $25.00. Paul

Yes I shall give that a try and even if it does work I am not after making lots of money I just wish it to go to a good home, or I shall trash it.