Decoder Drive Ic (Sn28723) - Canon A-1 Repair Manual

3.5 DECORDER DRIVER IC (SN28723)
80
This is the dr i ver IC for the viewfinder display. It
is mounted on a separate decoder driver flex which connects
to the main flex by a special small connector. The main
input to the decoder driver is the CPU'S 0 Bus. Since it
1s connected by a connector, the easiest method of
troubleshootinq is by replacement.
1 . I ADJ (lP)
Input to current adjustment circuit for seqment drive.
2. Diqits and Seqments
Each diqit is made of seven seqments. D2 thru D7 are
normal alphametric 7 seqment diqits . Dl is a special
digit . Six segments form the letter "M" for manual.
The seventh seqment is the decimal point between D6
and D7.
1) Diqits
BBBBBBf'1
~02'
03, 04,
05~.06'
07,
Finder
~-r----
Displ a y Di a phraqrn
Dl
01
Display
Fiq. 3-52
2) Seqments
Fiq. 3-53