8-Day
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.
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:
88:88
88
ETC
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)
Aerospace Display 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
Two-button operation
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
Craig Pearce
- Aircraft Clocks
of the World - Waltham
Aircraft Clock Corp.-
Barnstormers - Instruments/Clocks - Aerospace Display Systems - LC20 -
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