Gavilan Mobile Computer PSU brick Polarity

[KLund1]

Hello,
I have a Gavilan Mobile Computer. It is very good condition. unfortunately some clipped of the barrel end off the power brick. I have found one that will fit, but I am not sure about the polarity. There is no polarity symbol anywhere on the unit, documentation, or online pictures I could find. The cord has a white strip on one side, but that is not helpful.
This unit was produced in 1984. Do you think by this time the polarity could have been standardized to center pin positive?

 

[Chuck(G)]

Nope--even today, there's no standardization. Are there any external signal connectors? For example, if you have a DB25 for serial port, check for continuity between pin 7 (ground) and both sides of the power connector. The one that shows continuity is the negative pole of the power supply. The same can be done with external monitor connectors or parallel printer port connectors.

 

[KLund1]

Thanks you. Very helpful.
I got the polarity now!!!
I will remember this easy tip!!