Codan 8525B Series - Page 5

8525B/8528 Technical Service Manual Table of Contents iii
Publication No: 15-02036 Issue 6
4.5 Microprocessor Controller PCB (04-02451 & 04-03031)................................4-12
4.5.1 Microcontroller Bus ......................................................................4-12
4.5.2 Internal I
2
C Bus.............................................................................4-13
4.5.3 External Bus..................................................................................4-14
4.5.4 Reset and Watchdog Circuit..........................................................4-14
4.5.5 RS-232 Port (ALE Option Only)...................................................4-14
4.6 Motherboard and Chassis (02-02453)..............................................................4-15
4.6.1 Power Supplies..............................................................................4-15
4.6.2 Antenna Control Facility...............................................................4-15
4.6.3 Extended or Remote Control—Option R......................................4-15
4.6.4 External Microphone Audio Clamp..............................................4-16
4.6.5 Additional Audio Facilities—Option RC......................................4-16
4.6.6 Headphone Output—Option PH ...................................................4-16
4.6.7 CW Facility—Option M................................................................4-16
4.6.8 External Selective Call or RTTY—Option PS..............................4-16
4.6.9 AGC Dump Circuit .......................................................................4-17
4.7 8525B Front Panels and Control Head.............................................................4-17
4.7.1 Display PCB..................................................................................4-17
4.7.2 Switch Matrix................................................................................4-18
4.7.3 Digiswitches..................................................................................4-18
4.7.4 Microphone Amplifier and Interface.............................................4-18
4.8 8528 Front Panel and Control Head.................................................................4-19
4.8.1 Display PCB, LCD........................................................................4-19
4.8.2 Indicator and Display Dimming....................................................4-20
4.8.3 Links..............................................................................................4-20
4.8.4 Switch Matrix................................................................................4-21
4.8.5 Microphone Amplifier and Interface.............................................4-21
4.8.6 8532 Display Head........................................................................4-21