Most humble apologies on the time offset delay . . . . of reply.
Looking at your soldering, I believe that we can now not worry about the possibility of a solder joint connectivity issue.
With concentration now being on two aspects . . .
1. The provision of a DC supply of ~1.5 VDC to your clocks timer portion.
2. The provision and adequacy of the ~4.5 VDC supply to run the motor that drives the ball pendulum arm, for its 1
turn cycle and then a resting.
(Would my guess-timation of a 5-10 second cycle be correct, with an ensuing 50-55 second resting time ? )
Now I have done a re-read back, to see if you gave the summation of the battery voltage of its series strung cells.
Not finding it, so can I expect 3 series "C" cells for 4.5 VDC with new cells installed .
THEN we would see the battery stacks negative terminal coming into the top corner of the PCB.
The battery + comes into the bottom corner
NOW hows about we concentrate on that clocks power supply and have you take a single C cell and connect two wires **********one to each end and run those wires directly to the RED CIRCLE and BLACK CIRCLE in the top left corner of my mark up.
That will give constant DC battery power to the clocks dedicated 1 minute timer portion.
From other owners comments, we might now expect 3-4 months of run time from that single "C" cell, until the inability to run on that
cells depleted voltage level.
If you then plug in the wall wart and use it as it has been used for 10 yrs, we will then be depending upon that DC supply for the gear train motor drive and its associated ball pendulum drop.
If you can repeatedly have success in making that mechanism cycle by placing a wire short across the YELLOW or parallel connected RED switch wires, that portion is not being at fault.
*********
HOWYOUDODAT?
I'll just bet that your soldering iron doesn't have enough
THERMAL OOOOOOOOOOOOMMMMMPPPPPTTTTTTHHHHH to be able solder onto those end caps, with the cells metallic mass siphoning away heat like an ice cube.
I even think that my 320W Weller gun would be taking a loooong warm up time.
An alternate . . . . . is to prepare the wires ends by forming one of each ends into concentrically decreasing spirals that then get pressed into the cell centers and initially taped down to hold in place and then cut multiple cardboard squares 1/2 the diameter of the cell ends to press against the centers, and then tightly winding tape or twine binding from end to end, to continually hold pressure on the end caps.
Then the loose wire ends get soldered to the PCB's top left corners marked up RED & BLACK circle solder blobs.
Then hook up and see if the main 1 minute clock runs . . . . . and if ever stopping . . . . then confirm that the "C" cell is still feeding its required 1.5 VDC.
I think that when you read 0.85 VDC on that supply line, was when the screw to bared copper foils was shorting and altering the regulated supply.
Since, that thus created misconnection was affecting the two FAR right side transistors which form a voltage regulator circuit to develop the 1.5 VDC from the main supply voltage.
I am including this MARK UP addition below , which I will be explaining in detail if so required later. The RED line path is the power flow to the motor driver transistor .
LUCKILY, when you jumper wired from your red circle , you just applied 4.5 VDC direct to the gear train motor and bypassed the main driver transistor. Then, as soon as the bottom, red wired, micro switch closed, it cycled on its own until getting back to its park position.
Normally, consulting the referencing below, the RED 4.5 supply line ( less the .7 volt drop of the series inserted 1N4007 steering diode ) takes a foil path up sweep to connect to the top lead of a 4.7K resistor which then has the resistors bottom lead routed downward to 3 hole pad which it shares with the RED and Yellow switch wires.
Then, the timer, in making a yellow switch closure takes the voltage and current reduced output of that 4.7K resistor to the left to the base of the motor driver transistor where its conduction then starts the gear train motor.
Now lets experiment and therewith, hope for monthly updates of . . . its still running !. . .
HOWEVER, if it stops and
STILL has its 1.5 clock run voltage, I'm then fully suspect of that 1 RPM mechanism.
ITS MARK UP TYME . . . . . . . .
(With the worst central offensive blackened solder flux deposits colored over, to be able to see the foil paths below)
View attachment 56884
73's de Edd . . . . . .
I think that the person who invented autocorrect should burn in hello.