Hello all. Looking for a hand on this guy here.
I recapped the servo unit and it worked fine for a few hours until I put it away in the garage. Fast forward about 6mo or so when I decided to dig it out and give a listen.
Speed is uncontrolled at this point. The ground leg of the motor circuit isn't getting any servo action as far as I can tell. I see a varistor in there next to the freq generator input and am assuming that is the heart of this servo control. The freq is fed to a gain stage (transistor) and on to the varistor so as to vary resistance to ground. Higher V (freq) equals more resistance, which in turn slows the platter.
That's how I'm deciphering the circuit, in it's most basic form anyhow. And that's where I'm lost. Anyone take a look at the schematic and give me a possible lead here? Thanks much.
Sony TTS-3000 Manual - Professional Turntable Motor Unit - Vinyl Engine
I recapped the servo unit and it worked fine for a few hours until I put it away in the garage. Fast forward about 6mo or so when I decided to dig it out and give a listen.
Speed is uncontrolled at this point. The ground leg of the motor circuit isn't getting any servo action as far as I can tell. I see a varistor in there next to the freq generator input and am assuming that is the heart of this servo control. The freq is fed to a gain stage (transistor) and on to the varistor so as to vary resistance to ground. Higher V (freq) equals more resistance, which in turn slows the platter.
That's how I'm deciphering the circuit, in it's most basic form anyhow. And that's where I'm lost. Anyone take a look at the schematic and give me a possible lead here? Thanks much.
Sony TTS-3000 Manual - Professional Turntable Motor Unit - Vinyl Engine
The Circuit Description section of the service manual appears to describe how it works rather well, no?
Maybe, I'm not sure. I can't grasp the technical lingo... Just a lowly mechanic after all.
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