I used the TA-312 a lot while on active duty, really quite a whole lot. At the time I really didn’t appreciate just how useful and rugged these phones are.

The US Army recently removed these from inventory (last decade or so), which I think was a mistake given what they can do. They provide reliable communications for an area and do not give an interceptable signal like radios do. They are compact, can take a beating, and are quite simple to understand. I found a pair of these recently and decided to pick them up. One of them had a ringer that wouldn’t ring, so I did have to do some repair.

Despite using these phones extensively, I don’t believe I have ever seen the inside. I took my time, consulted what info I could find on the internet (including Signal Center | U.S. Army Signal Corps field telephones and switchboards) and identified what I needed to fix the phone with a broken ringer. The ringer is part “Buzzer BZ-23/PT” and is held in place by the 4 external screws and a small pin connecting the ringer assembly to the ringer volume control knob. There are two wires that require solder connections as well and are color coded so it is clear what goes where. This job looked intimidating at first, but was actually quite straightforward with patience, lots of photos, and referencing the SignalCenter website.

I got handset spaghetti cables and other miscellaneous parts from SignalCenter.com and the ringer/buzzer from Fair Radio Sales – Electronic Military and Industrial Surplus.

Replacing the handset spaghetti cable took some patience, but also was fairly straightforward to do. I took lots of photos but the individual cables are color coded so it actually wasn’t hard to do at all. The spaghetti cable has a small hook on either end that prevents the cable from backing out when it is pulled on. Fishing the small cables through the handset and phone body was not as difficult as I expected.

I don’t anticipate these phones being incredibly useful for amateur radio events, but they should be a very interesting addition as part of the overall setup I have when people visit the station in the field.

Thank you to Signal Center | U.S. Army Signal Corps field telephones and switchboards for the TA-312 information and parts and Fair Radio Sales – Electronic Military and Industrial Surplus for the “buzzer”.

I rarely saw the H45 on active duty, and when I did it was in the GP Small or medium tents. I have an M1950 Yukon stove same as I used with the hex tent on active duty, but with liquid fuel (diesel/mogas). Burning wood in the Yukon does work, but it takes frequent fire maintenance and it is difficult to manage temperature output with it. I also found coal to be difficult to burn in the Yukon, it just really isn’t set up to do this. Coal would be nice as a compact and long burning fuel.

I have seen the H45 on sale quite often, so I ordered one. The stove itself wasn’t much, but shipping for the large crate was expensive. The solid fuel component I was unable to find for sale anywhere. I had one made and I am happy with it, even if it’s heavier than the original.

My main worry was that the H45 would be too large and put out too much heat, but was pleasantly surprised to find that temperature control is much easier and even with the H45 vs Yukon. It is bigger than the Yukon, but in height and not really length so I don’t lose floorspace using it.

Using coal as a fuel works very well, with very long and even burn times, well beyond overnight without messing with it.

Ill keep the Yukon of course, it is more compact and easier to setup, but the H45 works well in an M1950 Hex tent and I expect ill use the H45 for most of my winter camping.

The original horn in the M37 matched its original electrical system, 24v. If you have a converted M37 there really isn’t a 12v horn that directly replaces a failed horn. On my truck, there is a modern 12v horn concealed that works out, but I wanted to use the original part if possible. The original horn was corroded in the interior, so this ruled out using a 12/24v converter. Vintage Power Wagons sells the 12v HYF-370 horn, which does fit in the MX-4003-UT housing with a bit of fitting.

The screws holes holding the HYF-370 together need drilled out a little to fit, and the HYF-370 came with a gasket between the two halves so I used a small amount of permatex with the gasket to compensate for the slightly larger holes. The original horn housing is held together with a large hand turnable part (below) which the HYF-370 does not have a hole for, but it does have a bolt shaft in the center so a metal dowel works to hold the thing together. Shaping and tapping this was fairly straightforward, I used M8x1.25 and 10NF32 taps, but I am not sure how consistent this would be.

I put terminals on the wires, soldered the other end to the douglas connector, hooked it up and it works. Sounds appropriately truck like, even if it likely does not sound exactly like an original.

If you have an M37 with 12v, and your horn isn’t working, this is one way to get this working and still look mostly correct.