IC29 7490

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Control board signal flow (Trace not completed)
Sample rate out to panel sw
IC297490
IC307490
IC31 7490
IC32 7490
IC337490
IC347490
IC357490
IC287400
1MHzRef in 1B
IC217420
IC287400
IC26M5946
IC23M5946
IC111017P
Gate time
Period/averaged
IC31017P
S
R
IC141027P
IC241017P
CK
IC51027P
IC61013P
IC71013P
IC81013P
IC41023P
X in19T
Parts no assign
IC151018P
IC161018P
IC171018P
IC181018P
IC10
IC19
IC191018P
IC35
IC26
IC197475
T28 B28
1s BCD
10s A
Edge connector
To counter board
Sample rate In 8B
IC127400
7400
To 7475en / 7490rst
T1 B1
IC11
IC20
IC27
IC1
Control board top view
2
IC Pinout
MC1023
MC1013,1027
MC1017
MC1018
2SC857
1013 85MHz AC Coupled JK-FF 1017 Level Translator
Sat logic to MECL 1018 Level Translator MECL to
Sat logic 1023 Dual 4 input OR NOR CLK
Driver 1027 120MHz AC Coupled JK-FF
200V/0.05A/100MHz Repl 2sc3467,68
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Follows are work memorandum
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Similar counter found on Yahoo auction
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