SR-52A rebuild project (SR-52A 942058 LTA4176)

[jebem]

Hi Alberto,

I can't really tell what version I have because I am temporally away from home, taking care of my old sick parents.

But I wouldn't worry to much about the version, as there are several releases of the 52 PCB (A to L, if my memory is not failing), and at least one version of the 52A, and of course several modifications were introduced, from circuit design, PCB layout, components selection (brand, floors, etc).

In the manual, look for the schematics diagrams, pages 37 and 39, you should be able to find on the right side of each page a symbol for the Motor, and one terminal is connected either to Q2 or to Q4, depending on the schematic version.
With a multimeter we can check where the motor is connected, it will be to a collector either to Q2 or to Q4.