Garrard Zero-100 speed control problem
My Garrard Zero-100 International idler wheel turntable won't slow down to proper speed. The Synchro-Lab motor in inscribed with the usual international blessings for 120 V/60Hz and 240V/50Hz, and the power cord inputs have little copper wire jumpers (what used to pass for a fuse in Britain) with guidance diagrams -- hence the International designation. Everything worked fine in England where I acquired it, but now that I have finally gotten around to unpacking it and coverting it for North American use, it is playing too fast.
With one neglible exception, everything is still original on this unit, including the magnificent plastic-&-cardboard plinth. The only change I have made is to attach the 60Hz strobe pattern donut to the underside of the platter. This paper donut sticker originally came with the unit, and was given to me by the original owner when he gave me the turntable. It just goes over the original 50Hz strobe donut sticker already on the underside of the platter.
I was about ready to start the tweaking and new plinth building process, but I did not expect to encounter problems with the speed after moving the voltage jumpers (fuses) to their correct positions. I have checked underneath to make sure the minor speed control adjustment is able to travel as far as it physically can, and it is functioning as designed. But even with it set as low as it can go, the speed is too fast, with both 33.3 and 45 rpm settings.
My suspicion is that while this International version only requires a fuse re-positioning to accomodate voltage changes and a change to the pattern for the strobe images, it requires a different wheel somewhere in the drive system to overcome the power supply cycle difference. Maybe this came with the unit when new, like the strobe pattern replacement donut, but was forgotten about by the time the original owner gave it to me decades later.
If this is actually the case, which wheel needs replacing? Do I need a smaller idler disk, or do I need a bigger version of the wheel attached to the motor shaft (the wheel which actually spins the idler disk which is contact with the platter)? Is either one of these easily available? I am not relishing the thought of either grinding down the idler wheel or putting tape on the outside of the motor spindle wheel pulley.
I confess that I have not yet actually measured the voltage inside to verify that it is indeed now 120V, so it is possible that maybe something is goofy with these wire jumper fuses. They are very short lengths with each end looped to fit over one of the four terminals available. When configured for 240V, the two jumpers BOTH sat on terminals 2 and 3. For 120V, the diagrams on the housing indicate that terminals 1 and 2 be joined together, and then 3 and 4 be joined together. I had thought that the different arrangements were only affecting whether the circuit was a parallel or series flow, but maybe there is more going on. Maybe I need TWO fuses on each leg of the 120V arrangement, since there were two on the one leg in the 240V configuration. I guess I could just wrap some more wire around the terminals and see...
I am open to all pearls of wisdom.