I think your Datsun external 35a and 50a alt ( pulleys) will work. Early internal regulated versions are similar to a Delco 10si if you are willing to, get a proper plug and by pass the regulator and monkey with the wiring.
If anyone is still out there looking for information on this, the voltage regulator for a 1972 Nissan/Datson 680 truck work. Denso PN TG026000-7200 and the Hitachi TL1Z-61D make sure it has the HBA12-2 connector. For the alternator I used a ACDelco 334-1547
Thanks for the info... I was given the 1700 2 years ago; my first tractor. Its been a learning experience and fun!. I now have a spread sheet on alternate parts and where I got them from to save money. Most brands of Alternators that I looked at are rebuilt Hitachi's including the ACDelco I mentioned earlier.
Old post I know, but I too have a 1700 with is having a voltage regulation issue. I picked up a new battery for it a few weeks ago and after bush hogging for a couple of hours I shut it down and noticed this hissing sound from the battery. Let it sit overnight and then started it back up this morning. At 1200 rpm, I was reading 18.4 volts across the battery terminals! I hope I didn't kill the battery (Die Hard Silver that was pretty expensive).
I have the original Hitachi alternator and I'm sure the original voltage regular as well.
This guy should fit the bill, right? (I would have to switch the connector over from the old one)
The second one looks more like what you need. The regulator I am currently using is a TL1Z-61D, I believe it is made by Hitachi. They need to be the HBA12-2 connector type.
I went and looked at the JDM link and the pictures showed a label "AVR-811". I looked up that number on the Newera website and that looks correct. (See Image)
It is solid state. However, it did not work. As soon as I started up, the charge light lit up and sure enough, I'm only getting 12.6 volts across the battery. So that was a waste of $40. They say returns not accepted if used, so since I did use it for all of 45 seconds, I guess it is now mine.
I took a look at the old one, and it seems to be ok. The small resistor is measuring 32 ohms, and the large one is measuring 42 ohms to the middle tap and 0.4 ohms from the middle tap to the other end. I guess I'll try to clean the relay contacts to see if that will help?