Having repaired an old Kambrook KD36 timer gifted to me by a friend, I'm sharing my circuit schematic and notes for anyone who might find them useful. The timer had been rendered unserviceable due to acid leakage from the two back-up batteries. The leaking acid had damaged some areas of the PCB and actually created a direct short circuit between +15 volts DC and ground. I was able to clean up the mess and resurrect the timer. These timers contain two PCBs. One is the front display and controller section and the PCB in the back provides the power supply, relay and battery back-up. These two PCBs are connected via a short ribbon cable. The back-up circuit might be useful to anyone wanting to design something similar for a project. I have not produced a schematic for the display/controller PCB.
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