shure 545 unidyne III

Greetings,

I have an older, used, "patent pending," Shure 545S Series 2 (pistol grip) microphone, and I'm gradually fixing it, having first reassembled the switch in the handle section.  I do get sound from the mic, but it is a little on the quiet, "hollow," and less low-frequency side.  I'm using it as high-impedance.

Greetings-

I recently bought an older Shure 545 (4-pin Amphenol era) on eBay, and while it works, it sounds a bit of the dog with voice: a greatly diminished low end, and reminiscent of talking through a paper towel tube.

Given there's only three parts to the mic: cartridge, transformed and wiring, it seems eminently repairable (by me), but I have no idea what's wrong with it. So I'm looking for pointers, links or URIs of forums that might help me diagnose the trouble with microphone.

So if you could help, I'd be greatly appreciative!

Can anybody help me with the correct cable wiring for a Shure 545 which has 4 pin amphenol connector (the type which changes impedance by changing the mic cable) very early I believe made in USA before Shure moved production to Mexico.
I bought 2 of these for my son but need to try to sort cables for him
I have seen an old thread by RemyRAD and others which seems to describe my problem (low output) so I think I have probably wired cable wrongly.
Can anyone help a newbie please? Pin numberings would help

So; I was talking with a friend of mine and we both professed our ignorance regarding the difference between these two mikes. Does one have a transformer and not the other? Aren't the capsules essentially the same? Was the SM57 simply an upgrade on cosmetics?

It would be interesting if anyone had some insight on this. at least to me, anyways!