SP10 Mk II vs Mk III

The answer to your question about whether or not the power supply governs the strobe function must be "yes", based on your own observation. It's most likely that the power supply supplies a voltage to the circuitry that runs the strobe. If that voltage is not present, the whole strobe circuit would not work. If it's as simple as that, repair should be no big deal. Have you replaced the electrolytic caps in the power supply? In a Mk II, if they have never been replaced before, then they are at least 25 years old. That's ancient for an electrolytic cap and maybe failure of one of those caps could account for your problem. Does the PS that can't power up the strobe still work properly for all other functions?

I have never replaced the caps, when I got my first SP10 about 10-12 years ago, It was in a McCurdy Plinth with some strange broadcast arm. The strobe did not work on it, so I began a several year hunt for a strobe. I found one on Ebay (remember the good old days on Ebay?? 1997-8!!) You could find anything there!!I never did try to replace the bulb assembly, my tech did not want to open the SP10 up. I never imagined it was a problem in the Power supply. That SP10 got sent down the road as I jumped into some other mad Turntable project. It was not until the last two SP10s that I started to suspect it was some kind of Power supply issue. Somewhere in my basement is an SP10 strobe!?
Thanks Lewm, I will get that PS looked at this week. Is a schematic needed or is it pretty obvious/straight forward?
John T

Schematic is available either from Vinyl Engine or from a pay site. (I can't remember where I got it.) If you're knowledgable, you may be able to read it yourself. I build tube stuff all the time, but I cannot make out what's going on in the SP10 schematic.

Does any one know of a good tech who can change out the capacitors since I wouldn't know a capacitor from a diode? Also, does anyone know of a tech comfortable with cleaning out and replacing the old bearing oil?

The SP10 MkII power supply has three voltages +5V, +32.5V and +140V. The 140V supply is used to power the strobe light. It is simple half wave rectifier circuit using a single diode, protected by a 315mA fuse - always check fuse F3 before anything else.