[Allen Corneau]

Howdy folks,

I picked up a Hitachi HT-MD03 turntable that has a small multi-pin connector
which connects to another component (receiver?) for power and audio.

I've cracked it open and I know which cables are audio and which are power.
The question: is there any way to find out the proper voltage for this unit?

I'd rather not drop $15 for the service manual if I can help it.

Any know off the top of their head? Or is there a better place to ask? Any
help would be appreciated.

Thanks,


Allen
--
Allen Corneau
Mastering Engineer
Essential Sound Mastering
www.esmastering.com

[Tim Schwartz]

Allen Corneau wrote:
Howdy folks,

I picked up a Hitachi HT-MD03 turntable that has a small multi-pin connector
which connects to another component (receiver?) for power and audio.

I've cracked it open and I know which cables are audio and which are power.
The question: is there any way to find out the proper voltage for this unit?

I'd rather not drop $15 for the service manual if I can help it.

Any know off the top of their head? Or is there a better place to ask? Any
help would be appreciated.

Thanks,


Allen

Allen,

One possibility is to open up the turntable and see if there is a
voltage listed on the motor. Most of the Small DC motors are 6, 9 or 12
volts. Of course if this is a direct drive servo unit, that won't tell
you much. You might also be able to tell from what sort of electronics
is inside the turntable. For example, if the power in leads to a
blocking diode with a smoothing capacitor and then a 6 volt regulator
IC, then I'd expect to need 9-12 volts to be applied to the regulator to
make sure it has enough voltage drop to work with.

Since the power come in on the same connector as the audio, I'd guess
that the turntable came with some sort of rack system. It might even
have the phono preamp built into the turntable. Have a look.

Regards,
Tim Schwartz
Bristol Electronics

[Mark D. Zacharias]

Tim Schwartz wrote:
Allen Corneau wrote:
Howdy folks,

I picked up a Hitachi HT-MD03 turntable that has a small multi-pin
connector which connects to another component (receiver?) for power
and audio. I've cracked it open and I know which cables are audio and
which are
power. The question: is there any way to find out the proper voltage
for this unit? I'd rather not drop $15 for the service manual if I can
help it.

Any know off the top of their head? Or is there a better place to
ask? Any help would be appreciated.

Thanks,


Allen

Allen,

One possibility is to open up the turntable and see if there is a
voltage listed on the motor. Most of the Small DC motors are 6, 9 or
12 volts. Of course if this is a direct drive servo unit, that won't
tell you much. You might also be able to tell from what sort of
electronics is inside the turntable. For example, if the power in
leads to a blocking diode with a smoothing capacitor and then a 6
volt regulator IC, then I'd expect to need 9-12 volts to be applied
to the regulator to make sure it has enough voltage drop to work with.

Since the power come in on the same connector as the audio, I'd guess
that the turntable came with some sort of rack system. It might even
have the phono preamp built into the turntable. Have a look.

Regards,
Tim Schwartz
Bristol Electronics

12 volts would be pretty common for this application. Maybe use a limiting
resistor and a variable power supply and just experiment. Run the voltage
down to the point where the motor drops out, then increase the voltage at
least 25 % or so. Might give you an idea of about where it ought to be...

Mark Z.

[Allen Corneau]

On 4/23/07 6:08 AM, in article , "Tim Schwartz"
wrote:



One possibility is to open up the turntable and see if there is a
voltage listed on the motor. Most of the Small DC motors are 6, 9 or 12
volts.

Tim,

First off, thanks for your help.

I looked inside again and there was no voltage marked on the motor, but a
Google search on the part number helped me find out that it's 9 volts.

Thanks,


Allen
--
Allen Corneau
Mastering Engineer
Essential Sound Mastering
www.esmastering.com