How do i fix a Malibu timer ML121RT to override the unit to use a separate timer?

SOURCE: Wiring diagram for the ML121RT?

You connect the lights to the A and B terminal.

The C terminal is used for an optional photo control.

SOURCE: I purchase a Malibu ML600TW.

With the 600 watt ML series, there are two sets of a-b-c terminals. C terminals are used with photo eye.
Connect 300 watts of bulbs to one set a-b terminals, connect 300 watts to other set of a-b terminals.
I'm not sure what is inside the power pack. However if you run less than or more than 600 watts or let your bulbs burn out for any length of time, the power pack can burn out. Save your receipt for limited 5-year warranty.

For your benefit, open following link for more information on ML power packs, plus troubleshoot, plus tips to keep power pack from burning out, and links to trippers:
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html

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SOURCE: two things, what size and

ML series power pack has 2 sets of A-B-C terminals.
1) The terminals are not on separate circuits.
2) Typically, Intermatic timers have 10-32 screw.
Open following link for Intermatic/Malibu resources, tips and links to Malibu and Intermatic manuals.
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html

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SOURCE: The timer on my Malibu

Some people report taking apart clock module and cleaning gears.
Others report gears are stripped out.

Might be easiest to buy cheap plug-in timer, set power pack to override, then plug power pack into cheap timer.

Timer clock module is not sold separately.
With receipt, power pack has limited warranty against workmanship defects.
Open following link for power pack tips and resources:
http://waterheatertimer.org/Malibu-power-pack-stopped-working.html

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