When 15 yr old pool pump motor died (?) I ordered a brand new motor. Installed the new motor. Only electrical work we did was to unwire and to rewire the power line to the motor. Never touched the main or the 2 timer connections (sidebyside timers).
The new motor worked like a charm. A day later I realized that the timer for the booster pump had stopped. So I started using the booster timer switch manually. The power comes from the motor timer, so the pool motor has to be ON.
About 10 days later the pool motor stopped while the timer was ON. Now BOTH timers have stopped working, though there is power. We checked for power at all connections all the way down to the motor. There is power everywhere.
I took the brand-new motor to the pool store and had it bench-tested it would not work.
The booster pump is still working. The small timer motors on the back of the panel indicate power. Some friends told me I should change these Intermatic small motors.
In the meantime I am waiting for the new motor to arrive.
BUT my WORRY is all those 1 week apart timer failures. Is this a coincidence or is there a possibility of a short or another reason that might result in frying the new motor?
PS- when pool pump timer switch is on the booster pump still works...

Should I just change the two small timer motors and install the new motor,
Or is there anything further I should look into.

Help appreciated.

Your motors work, you bench tested. You have power everywhere so that brings the timers in the line of fire. Bypass the timers and confirm your motors run on manual, if so R&R the timers.

I am sorry if my story was confusing... booster motor works in its usual place.. only by means of manual swich.
New Pool pump motor AOsmith 1,5 HP ( after working perfectly for 10 days )
did NOT work when bench tested That is why I am getting another new motor.
Both timers do not work but there is power between connectors and to the timer motors.

First the old motor died.
As soon as we installed the new motor for the pool pump the Timer for the booster died.
The new motor worked perfect for 10 days and in the middle of the 8 hour working cycle
Both the pool motor timer and the pool motor stopped.
Now both timers are not working but the booster pump works when tested.

I also ordered 2 intermatic 1573 timer motors for both timers. And the new motor is on its way.

My question is this; 2 motor and 2 timers dying within short intervals seems to be not so coincidental!! Is there anything else that I should check before I change the 2 timer motors and install the new motor ?