Converting 50Hz to 60Hz???

[Audio_idiot]

Hi,
Since its a DC direct drive, I would suggest installing a mosfet driver to regulate the supply voltage to the motor, you can even use a pot to trim the voltage until you achieve the requive speed.

Cheers

Ken

[Steerpike]

Since its a DC direct drive, I would suggest installing a mosfet driver to regulate the supply voltage to the motor, you can even use a pot to trim the voltage until you achieve the requive speed.

You can't do that. It's an FG servo system, so it doesn't care what the supply voltage is either (withing certain extrema). It measures the platter speed by means of a magnetic stripe, and then adjusts the motor drive, regardless of the power supply voltage.

[Antripodean]

Thanks for all your replies. To answer a question, it does run when fed the right voltage thru the stepdown transformer. It is the speed that is the question. I have to buy a strobe light to check it.

[Steerpike]

I have to buy a strobe light to check it.

No you don't. Ordinary household lighting works fine. Incandescent (filament) lamps work OK, but fluorescents are better. (tube fluorescents with coil ballasts, not the new CFL types, which mostly have their own oscillators in them)

All you need to do is get a strobe disc for 50Hz (print out one that you download from the www - try the Vinyl Engine library)

It's a quartz PLL drive, so if the speed *is* wrong, it is possibly a fault in the electronics. But the service manual is downloadable for free. I've just had a look at it, and there are internal calibration adjustments for the two speeds.

[eclectic2k]

Originally posted by Steerpike
No you don't. Ordinary household lighting works fine. Incandescent (filament) lamps work OK, but fluorescents are better. (tube fluorescents with coil ballasts, not the new CFL types, which mostly have their own oscillators in them)

All you need to do is get a strobe disc for 50Hz (print out one that you download from the www - try the Vinyl Engine library)

Second that. - It works quite well in fact. years ago I made my own "60Hz strobe disc" and used it to check my TT. Only noticed fairly recently that there are some easlily available for download - shouldn't be hard to find a 50Hz disc you can print out.

With incandescent, it's a bit of an eye test, but as Steerpike says, an old fluorescent works nicely. - just make sure the room is fairly dim or dark aside from your "strobe" light

[peranders]

http://www.vinylengine.com/

[AndrewT]

stick a post it on the turntable.
Count the revolutions for three minutes.
33 1/3RPM comes to 100 revs/3minutes.

if you get 99.5 revs you are 0.5% slow.
if you get 100 3/4revs you are 0.75%fast.

It's that easy.

You may find it easier to stopwatch 100revs and see how close to 180seconds you get.

[Antripodean]

Thanks for the suggestions. I now have a strobe disc and will check it tonight. Trying to find a flourescent light still. Seems like they have gone out of fashion

[AndrewT]

the compact fluorescents have almost replaced the filament type.

[Steerpike]

You can - if pressed- make up a cheap strobe with any LED, which must be powered by *full-wave rectified* AC, but NO smoothing capacitor. And a suitable current limiting resistor (1k for 12V ac.)

12V full wave rectified AC can be got from an *old* AC wall transformer/adapter, as used for portable tape recorders, answering machines, etc. You need the old style with transformer - not a modern switched-mode one.
All you do is chop out the big smoothing capacitor.