I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
Any help would be appreciated.
Thanks in advance.
Leon

Hi Leon

Most likely a thermister, heat sensitive resistor. The glass cylinder may have carbon powder or small wire inside? Might be able to measure resistance with an ohm meter? Does the schematic show a value for this part?

Norm

:I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
:Any help would be appreciated.
:Thanks in advance.
:Leon

Hi Norm

I was wondering if it was a thermister but both copies of schematics does not show a value. If there is a small wire still in the glass cylinder then it is very small. I have not checked it under a magnifying glass but will.
Thanks Norm.

:Hi Leon
:
: Most likely a thermister, heat sensitive resistor. The glass cylinder may have carbon powder or small wire inside? Might be able to measure resistance with an ohm meter? Does the schematic show a value for this part?
:
:Norm
:
::I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
::Any help would be appreciated.
::Thanks in advance.
::Leon

A resistor symbol with a circle is a lamp. If it looks like a fuse see if you can read volts and watts on end. Probably rated at 3 watts 115 V.
Bill

:Hi Norm
:
:I was wondering if it was a thermister but both copies of schematics does not show a value. If there is a small wire still in the glass cylinder then it is very small. I have not checked it under a magnifying glass but will.
:Thanks Norm.
:
::Hi Leon
::
:: Most likely a thermister, heat sensitive resistor. The glass cylinder may have carbon powder or small wire inside? Might be able to measure resistance with an ohm meter? Does the schematic show a value for this part?
::
::Norm
::
:::I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
:::Any help would be appreciated.
:::Thanks in advance.
:::Leon
:
:

Hi Bill

This component is under the chassis of the TE-22. To have a lamp there would not make sense. No need for a fuse in this location either.....

Leon

:A resistor symbol with a circle is a lamp. If it looks like a fuse see if you can read volts and watts on end. Probably rated at 3 watts 115 V.
:Bill
:
:
:
::Hi Norm
::
::I was wondering if it was a thermister but both copies of schematics does not show a value. If there is a small wire still in the glass cylinder then it is very small. I have not checked it under a magnifying glass but will.
::Thanks Norm.
::
:::Hi Leon
:::
::: Most likely a thermister, heat sensitive resistor. The glass cylinder may have carbon powder or small wire inside? Might be able to measure resistance with an ohm meter? Does the schematic show a value for this part?
:::
:::Norm
:::
::::I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
::::Any help would be appreciated.
::::Thanks in advance.
::::Leon
::
::

Hi

Lamps were used under a chassis not for light but as a thermistor. A lamp changes resistance as it heats.

Norm

:Hi Bill
:
:This component is under the chassis of the TE-22. To have a lamp there would not make sense. No need for a fuse in this location either.....
:
:Leon
:
::A resistor symbol with a circle is a lamp. If it looks like a fuse see if you can read volts and watts on end. Probably rated at 3 watts 115 V.
::Bill
::
::
::
:::Hi Norm
:::
:::I was wondering if it was a thermister but both copies of schematics does not show a value. If there is a small wire still in the glass cylinder then it is very small. I have not checked it under a magnifying glass but will.
:::Thanks Norm.
:::
::::Hi Leon
::::
:::: Most likely a thermister, heat sensitive resistor. The glass cylinder may have carbon powder or small wire inside? Might be able to measure resistance with an ohm meter? Does the schematic show a value for this part?
::::
::::Norm
::::
:::::I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
:::::Any help would be appreciated.
:::::Thanks in advance.
:::::Leon
:::
:::

Hi Leon,

You'll find this lamp in the oscillator circuit. Heating and cooling of the filament affects the oscillations...or the oscillations affect the filament by heating or cooling, changing the resistance, keeping the oscillations constant. Help!
It's been too long, I'm just a mechanical doer nowadays.

:Hi Bill
:
:This component is under the chassis of the TE-22. To have a lamp there would not make sense. No need for a fuse in this location either.....
:
:Leon
:
::A resistor symbol with a circle is a lamp. If it looks like a fuse see if you can read volts and watts on end. Probably rated at 3 watts 115 V.
::Bill
::
::
::
:::Hi Norm
:::
:::I was wondering if it was a thermister but both copies of schematics does not show a value. If there is a small wire still in the glass cylinder then it is very small. I have not checked it under a magnifying glass but will.
:::Thanks Norm.
:::
::::Hi Leon
::::
:::: Most likely a thermister, heat sensitive resistor. The glass cylinder may have carbon powder or small wire inside? Might be able to measure resistance with an ohm meter? Does the schematic show a value for this part?
::::
::::Norm
::::
:::::I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
:::::Any help would be appreciated.
:::::Thanks in advance.
:::::Leon
:::
:::

Being Lafayette and of older? vintage I would just bet that unit
is using a Wien-Bridge oscillator circuit and they very,very commonly
use a lamp in the neg feedback loop circuitry for amplitude regulation.
A 3W/115V like a 3S6 lamp was common , however I have also seen a
7W lamp unit...all just according to design parameters.Even the
use of a miniature lamp in some military designs. Why don't you
check out components in the osc circuitry and see if there might
be a lamp or a dupe of your part in the unit, considering that
one might have been a spare part.
73's de Edd

:I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
:Any help would be appreciated.
:Thanks in advance.
:Leon

:Being Lafayette and of older? vintage I would just bet that unit
:is using a Wien-Bridge oscillator circuit and they very,very commonly
:use a lamp in the neg feedback loop circuitry for amplitude regulation.
:A 3W/115V like a 3S6 lamp was common , however I have also seen a
:7W lamp unit...all just according to design parameters.Even the
:use of a miniature lamp in some military designs. Why don't you
:check out components in the osc circuitry and see if there might
:be a lamp or a dupe of your part in the unit, considering that
:one might have been a spare part.
:73's de Edd
PeeEss:I do see that Tannenbaum does have your TE-22 manual...no freebie,
of course.
:
:
::I have picked up a Layfette TE-22 Sine-Square Wave Audio Generator. The circuit diagram shows one component that I am trying to identify. The symbol on the schematic is of a resistor but with a circle drawn around it. One one schematic it has a 'Th' beside it and on another it has 'ST' beside it. When I picked this up I found, taped to the inside, a schematic and a glass cylinder (1/2" x 1/16"). This cylinder has two leads on it and nothing inside connecting the leads. I am pretty sure this is what is shown on the schematic as TH/ST but am not sure. It does not exist in the circuit and the oscillator does not start. I am thinking whoever had this before had this component go bad and removed it. Is it a fuse? or a special type of resistor?
::Any help would be appreciated.
::Thanks in advance.
::Leon