Waltham Watch Co.
Mfrs part no. CDIA
F.S.S.C. NO R-88-c-590-100
Contract No. NOA (S)-577
The case is just under 3.25" x 3.25". The back has what appears to be 2
adjustments for rate?
Used on the Lockheed Ventura.
|1 Second Exposure, UV Flashight - you can
see 5 movements in the 1 second
Click on photo to see a larger version and if the cursor is (+) click again
|I've seen some people comment
that these clocks have "glow in the dark" marking.
That's to say the hands and numbers will glow in the dark after being exposed to white light.
They were not designed with "glow in the dark" capabilities, rather they were designed
to be used with UV cockpit lights. That way the pilot can read the instruments at night
without having his night vision diminished.
|White Light Illuminating
||UV Light Illuminating clock
1. remove plug behing wind/set knob.
2. While holding wind/set shaft from behind with flat blade screwdriver,
unscrew knob using pliers or other way to grab it.
3. remove 8 screws behind bezel
4. remove 3 scrfews that hold mechanism into case.
|Waltham Watch Co.
U.S.A. 8 Days
Adj. Temp. & 1 Pos.
Waltham Clock co inc
Electronic Aircraft Clock
6648-01-874-83 (<- very illegible and sure to have many wrong numbers)
Astrotech LC-20 is the current Model
The case is 2.385" x 2.385" square. The circular part in back would pass through a 2" diameter hole.
The SEL and CTRL appear to be push buttons.
A sticker on the cylindrical part says:
Functional Test, Accept (QA stamp), Bell Helicopter Textron.
In the correct lighting you can see on the front the LCD patterns:
Inside there are what appears to be hundreds of fiber optic light
pipes to back light the LCD.
If the fiberoptic bundle is unplugged from the lamp and light shined into it, the whole face of the clock is illuminated, so the fibers are not going to specific locations, they just provide even back lighting.
There are a few date codes that indicate this was made after 1992.
A 3.65 Volt Lithium 850 mAh, 1/2 AA size battery marked TL-1250 is connected to the 71701BG IC. Radio Shack has an replacement RS 23-026 = TL5101
On one of the printed circuit boards there is a small transparent
surface mount crystal marked "2.0000 M" and there is a seperate
2.097152 MHz crystal in a can,
the IC marked 71701BG, an 8-pin IC marked "34164, 2335" and the are a number of discrete components.
The 6-pin MIL connector on the
back is marked:
92 26 SOURIAU FR MS27466 T 9B35 P
The connector has an Outside Diameter of 0.565" with 2 lugs higher and an I.D. of 0.445" with 5 groves going to a larger diameter.
There are 6 wires going to the connector:
1 - +28 DC
2 - 28V Return
3 - See notes
4 - 5V AC/DC Return
5 - Safety Ground
6 - Blue - spare - provision for second lamp - not used on this model
The Black, White & Green wires are for supplying power to the
unit and are under investigation.
(In the process of working on the wiring, 2 broken solder joints were found - helicopter environment)
Systems (ADS) Ph 215 8226090 , Fax 215 8227974
- - Makes the LC-20 which is the same clock!
Astrotech - repairs aviation chronometers - Products - LC20
Liquid Crystal Display for excellent sunlight readability
24 hour clock
Sweep second hand
24 hour elapsed timer
Back lighting for night operations
Front mounts into aircraft panel
Internal keep-alive battery - Radio Shack has an replacement RS 23-026 = TL5101
Fitted to a wide variety of military aircraft
This was sold on eBay as an A11, but all of them I've seen have the set/wind stem sticking straight out. The dial is stamped A.F. U.S. Army, Type A-11. Maybe this was a prototype or a later version of the A-11? This type of stem that sticks out at the 45 degree angle is what I remember as applicable to clocks used in time and distance rallies. If this was surface mounted on a wooden instrument panel the stem would be above the surface and could be wound/set.
Fig 4 Note dial stamped:
A.F. U.S. Army, Type A-11
Fig 5 With UV light (see Cockpit UV Lights)
The hands are not glowing, maybe they are old Radium dials (Wiki: Dials, Girls))? Radium dials up to 1960.
Note the second hand moved.
Three brass screws on back of main body (left) hold movement to back. Four smaller black screws hold front-glass to body.
Fig 7 There was no oil on a number of the pivots! Maybe the clockwork was cleaned but not oiled?
Fig 8 Body and Front-glass partially opened.
Has been running for half an hour so far.
31 Aug 2018 - it has been running for a couple of days and the time is correct.
4 Sep 2018 still running - 6 days total
5 Sep 2018 - 7 days
8 Sep 2018 stopped at 12:20 (just after midnight) 10 days actual run time.
Without taking my thumb and first finger off the winder, it takes about 20 back and forth movements to wind.
It takes some rocking back and forth to get the balance wheel going.
stopped 3:07 am 16 Sep 2018 - 8 days run time.
Started as soon as wound, not shaking needed.
M800 series of digital aircraft clocks.
4486077 Digital meter with uniform illumination and less inadvertent setting, David N. Torresdal, DAVTRON Inc, 1984-12-04, - better illumination and prevent inadvertent resetting.
Craig Pearce - Aircraft
Clocks of the World - Waltham
Aircraft Clock Corp.-
Barnstormers - Instruments/Clocks - Aerospace Display Systems - LC20 -
Back to Brooke's, PRC68, Products for Sale, Personal Home, Time & Frequency, Military Information page
Page created 2000 (Wiki:Y2K)