[kiwianalog]

I am concerned that a 2ndhand kenwood turntable I bought is using what seems
to me a very unusual and prone to failure method of detecting speed, it is a
directdrive quartz pll table, no strobe or user speed adjustment. Under the
platter is a small metal rod that protrudes down vertically and hit's a
plastic lever everytime the platter does a full rotation, I see no other
obvious speed sensors, this seems like a crap way to do it, can someone
confirm that i am understanding what i am seeing or could this be for
something else that i don't know about.

[Karl Uppiano]

"kiwianalog" kiwi@analog wrote in message
...
I am concerned that a 2ndhand kenwood turntable I bought is using what
seems
to me a very unusual and prone to failure method of detecting speed, it is
a
directdrive quartz pll table, no strobe or user speed adjustment. Under
the
platter is a small metal rod that protrudes down vertically and hit's a
plastic lever everytime the platter does a full rotation, I see no other
obvious speed sensors, this seems like a crap way to do it, can someone
confirm that i am understanding what i am seeing or could this be for
something else that i don't know about.

The mechanism you describe sounds like the auto-shutoff. PLL Quartz
turntables use an electromagnetic tachometer to continuously compare the
motor speed with a quartz reference oscillator.

[@(none)]

Karl Uppiano wrote:
"kiwianalog" kiwi@analog wrote in message
...

I am concerned that a 2ndhand kenwood turntable I bought is using what
seems
to me a very unusual and prone to failure method of detecting speed, it is
a
directdrive quartz pll table, no strobe or user speed adjustment. Under
the
platter is a small metal rod that protrudes down vertically and hit's a
plastic lever everytime the platter does a full rotation, I see no other
obvious speed sensors, this seems like a crap way to do it, can someone
confirm that i am understanding what i am seeing or could this be for
something else that i don't know about.


The mechanism you describe sounds like the auto-shutoff. PLL Quartz
turntables use an electromagnetic tachometer to continuously compare the
motor speed with a quartz reference oscillator.

And often, some sort of "tachometer" is build inside the motor.
Check if there are more than 2 wires running from the motor to
a control-pcb.

Andre

[Laurence Payne]

On Wed, 22 Nov 2006 21:03:56 +1300, "kiwianalog" kiwi@analog wrote:

I am concerned that a 2ndhand kenwood turntable I bought is using what seems
to me a very unusual and prone to failure method of detecting speed, it is a
directdrive quartz pll table, no strobe or user speed adjustment. Under the
platter is a small metal rod that protrudes down vertically and hit's a
plastic lever everytime the platter does a full rotation, I see no other
obvious speed sensors, this seems like a crap way to do it, can someone
confirm that i am understanding what i am seeing or could this be for
something else that i don't know about.



This isn't a speed sensor. Probably an auto-stop mechanism. Speed
will be regulated by a feedback system within the motor.

Are you having speed problems with this unit? If not, relax :-)

[Mark D. Zacharias]

Laurence Payne wrote:
On Wed, 22 Nov 2006 21:03:56 +1300, "kiwianalog" kiwi@analog wrote:

I am concerned that a 2ndhand kenwood turntable I bought is using
what seems to me a very unusual and prone to failure method of
detecting speed, it is a directdrive quartz pll table, no strobe or
user speed adjustment. Under the platter is a small metal rod that
protrudes down vertically and hit's a plastic lever everytime the
platter does a full rotation, I see no other obvious speed sensors,
this seems like a crap way to do it, can someone confirm that i am
understanding what i am seeing or could this be for something else
that i don't know about.



This isn't a speed sensor. Probably an auto-stop mechanism. Speed
will be regulated by a feedback system within the motor.

Are you having speed problems with this unit? If not, relax :-)

It definitely trips the auto-return cycle. I have a Kenwood KP-5022 which
has this, and Pioneer used it on the PL-A35 model.

Mark Z.

[Robert Gault]

Mark D. Zacharias wrote:


On Wed, 22 Nov 2006 21:03:56 +1300, "kiwianalog" kiwi@analog wrote:


I am concerned that a 2ndhand kenwood turntable I bought is using
what seems to me a very unusual and prone to failure method of
detecting speed, it is a directdrive quartz pll table, no strobe or
user speed adjustment. Under the platter is a small metal rod that
protrudes down vertically and hit's a plastic lever everytime the
platter does a full rotation, I see no other obvious speed sensors,
this seems like a crap way to do it, can someone confirm that i am
understanding what i am seeing or could this be for something else
that i don't know about.





It definitely trips the auto-return cycle. I have a Kenwood KP-5022 which
has this, and Pioneer used it on the PL-A35 model.

Mark Z.



Which means that the turntable needs adjustment. The auto-return should
make contact when the arm reaches the "end of the record" grooves not
while playing music. That rod ought to be linked to the arm with an
adjustable collar so that the rod can be moved relative to the arm. The
rod should be set to make contact only when the end of a record is reached.

If this rod makes contact at each revolution while playing a record, it
must produce some audibly bad effect.

[kiwianalog]

"Mark D. Zacharias" wrote in message
. net...
Laurence Payne wrote:
On Wed, 22 Nov 2006 21:03:56 +1300, "kiwianalog" kiwi@analog wrote:

I am concerned that a 2ndhand kenwood turntable I bought is using
what seems to me a very unusual and prone to failure method of
detecting speed, it is a directdrive quartz pll table, no strobe or
user speed adjustment. Under the platter is a small metal rod that
protrudes down vertically and hit's a plastic lever everytime the
platter does a full rotation, I see no other obvious speed sensors,
this seems like a crap way to do it, can someone confirm that i am
understanding what i am seeing or could this be for something else
that i don't know about.



This isn't a speed sensor. Probably an auto-stop mechanism. Speed
will be regulated by a feedback system within the motor.

Are you having speed problems with this unit? If not, relax :-)

It definitely trips the auto-return cycle. I have a Kenwood KP-5022 which
has this, and Pioneer used it on the PL-A35 model.

Mark Z.


Thanks everyone for clearing this up for me.

[kiwianalog]

"Robert Gault" wrote in message
...
Mark D. Zacharias wrote:


On Wed, 22 Nov 2006 21:03:56 +1300, "kiwianalog" kiwi@analog wrote:


I am concerned that a 2ndhand kenwood turntable I bought is using
what seems to me a very unusual and prone to failure method of
detecting speed, it is a directdrive quartz pll table, no strobe or
user speed adjustment. Under the platter is a small metal rod that
protrudes down vertically and hit's a plastic lever everytime the
platter does a full rotation, I see no other obvious speed sensors,
this seems like a crap way to do it, can someone confirm that i am
understanding what i am seeing or could this be for something else
that i don't know about.





It definitely trips the auto-return cycle. I have a Kenwood KP-5022
which
has this, and Pioneer used it on the PL-A35 model.

Mark Z.



Which means that the turntable needs adjustment. The auto-return should
make contact when the arm reaches the "end of the record" grooves not
while playing music. That rod ought to be linked to the arm with an
adjustable collar so that the rod can be moved relative to the arm. The
rod should be set to make contact only when the end of a record is
reached.

If this rod makes contact at each revolution while playing a record, it
must produce some audibly bad effect.

Thanks for that explanation, I will try and see if I can figure it out then.

[Geoff]

kiwianalog wrote:
I am concerned that a 2ndhand kenwood turntable I bought is using
what seems to me a very unusual and prone to failure method of
detecting speed, it is a directdrive quartz pll table, no strobe or
user speed adjustment. Under the platter is a small metal rod that
protrudes down vertically and hit's a plastic lever everytime the
platter does a full rotation, I see no other obvious speed sensors,
this seems like a crap way to do it, can someone confirm that i am
understanding what i am seeing or could this be for something else
that i don't know about.

Does the turntable not perform well ? If it is to do with speed (which I
doubt) , and the turntable works well, then it ain't a crap way to do it.

geoff