Identifying a regulated alternator, plus running reg alt on ext reg circuit.

[clubagreenie]

Not Rover related but in the stable I have a 1969 Toyota Crown MS55 Super Deluxe. Just getting back into getting it re running and the original charging circuit is an externally regulated alternator. Now the regulator is still there and part of the circuit but the original alternator is missing &/or damaged and put out to pasture. I have another but am not sure if it's the same or not. Still takes the same plug (3 pin S 12v sense ,L dash lamp ,Ign switched ignition source) plus +'ve pole terminal to battery.

I've gotten it to turn over (not bad since I rebuilt the engine 8 years ago and it's been sitting since) but the wiring is in a pretty ordinary state and I'll not only be replacing it but upgrading things like wiring size (for lights etc) and so on.

Question is, how do I ID the alt I have (can I externally?). Obviously if it's internally reg'd I need to remove the ext reg. If it has been run with both internal and external regs what potential damage is there?

[bee utey]

Hook it up with 12V to S, a globe to L, spin it up and see if it regulates (multimeter connected to battery). I had a replacement jap alternator recently where the exact same problem existed, all I had to do was connect a bridging wire across the old regulator plug to get the light from the dash to connect to the light wire from the replacement (internal reg) alternator. All that happened with 2 regs is that it didn't work.

[clubagreenie]

Thanks, nothing on that front comes up current wise. Removed it and in doing so heard a rattly. Took to the local auto leccy and he dismantled while I was there and 2 diodes had fallen off completely, and they all were totally stuffed, allowing less than 1amp across them according to his diode tester thingy.

$215- for a replacement diode board. $185- for a replacement alternator or $140- for a different new alternator but with the same diode board as the other "new $215-" that I could buy on it's own.