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 clock
||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
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
mount crystal marked "2.0000 M" and there is a seperate 2.097152 MHz
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
and are under investigation.
(In the process of working on the wiring, 2 broken solder joints were found - helicopter environment)
(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
of the World - Waltham
Aircraft Clock Corp.-
Barnstormers - Instruments/Clocks - Aerospace Display Systems - LC20 -
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