I need a service/parts manual for a Waltham GCT AN-5740 watch. I've searched the site and Google and can't seem to locate one. I have TM 9-1575 but it doesn't cover the GCT watch. Does anyone know where I can find the manual?

Thanks,

John

If you will do a google search and put in "manual for GCT AN 5740" you will find a PDF file you can download which is the official manual for the watches.

[NOTE] I actually missed the "Waltham" part of your post earlier. The manual I referenced above covers the Hamilton 22 Jewel 4992B with the center seconds sweep.

Some pictures of what you have and a serial number will help. The three main manufacturers of the AN-5740 and AN-5740-1 were The Hamilton Watch Co., The Elgin National Watch Co. and the Waltham Watch Co. All were made to the same military specifications, and were marked AN-5740. I don't Have the actual production numbers with me, but the Hamilton is much more common than the Elgin and Waltham. All were made for Army and Navy use for aircraft navigation. The similarities between the different brands are in the dial, case, and movement quality. Otherwise, the construction and design of the watch movements are as different as Ford engines are from Chrysler.

Waltham made several different models, some were second sweep models with 22 jewels, A Weems model 23 jewel Wind Indicator Navigation watch, a Grade 16-A with 22 jewels, adj 3 pos. and a 24 hour dial, and a Grade 1622 with 22 jewels adj. 5 pos. They also made the Waltham 23 Jewel Vanguard, Wind Indicator, Adj 6 positions, marked U.S. Army A.C. under the balance with the 12 hour dial and the regular second hand bit at 6 o'clock position ....



regards,
bb

OK, thanks BB. I appreciate it.

John

I looked and could only find the manual for the Hamilton GCT. My Waltham GCT is missing the BW and I'm trying to figure out if a Vanguard BW is the same as the GCT. I tried a BW (Balance Wheel) from a Vanguard 23 jewel and it didn't seem to fit. Has anyone had the same problem?

John

I should add that the main spring barrel and arbor are different than a Vanguard. They more closely resemble a Hamilton Barrel. The main spring is also different.

John

Pictures, serial number, markings on mvmt, case, dial, color of dial, etc. will help John.

regards,
bb

OK, I'll attach a few pics. The serial number is hard to read on the photo. It's 31789429.

The dial and case back.

OK- while I am no expert on these watches, you probably know more than I do, but I will tell you what I know and we will welcome other contributors to add to the thread and to answer any unanswered questions not covered.

This is the Waltham Master Navigation watch also called the "Deck Watch" Model 1908, Grade 1622, 16 refers to its size, and 22 is the number of jewels.

This watch, 31,789,429 is one of 5,000 TOTAL PRODUCED and produced May 1944. The run it was made in started with 31,788,001 and ended with 31,793,000. It is pendant-set with the "hack feature". It has the center sweep seconds hand with a 24 hour train and dial. It was based on the Model A 16A and used the same "half whiplash" regulator as the Vanguard.

They were a component of the aircraft navigation instrument set issued by the Army Air Corps. They came in base metal cases with and without ordnance markings on the case backs.

Waltham, Elgin, Hamilton, and Longines made GCT watches. Here are the number each manufacturer produced:
Waltham-5,000
Elgin-20,800
Hamilton-140,000
Longines-Unknown

The Waltham GCT was Adjusted to 3 Positions so it was meant to be kept in the "Dial-Up" position.

That's all of my "saved/collected" information I have saved from IHC, Google, and various expert authors regarding your watch.

regards,
bb

Well, the good news is I figured out what the problem was. The pallet fork was wrong. I bought this from EBAY as a parts watch. I was able to see the difference when I compared it to the Vanguard. The fork was to short to engage the roller jewel properly. She's ticking away as we speak. From what I've observed the BW and pallet fork seem to be the same as the Vanguard. I was surprised that the main spring barrel and arbor were different. The main spring is a T end like a Hamilton, but it also has a whole at the end like a Waltham. The main spring barrel has both the rectangular hole for the T end and also the tang on the inside wall for a Waltham spring. I don't know if this is normal or a modification. Maybe someone can fill in the holes. Now to get the whole thing working.

Thanks for the help,

John