JFET identification

J

JW

Guest
Hi all,

Looking for a datasheet or any info on a FET used in a Keithley 2000
location Q105. The service manual lists it as:
TRANS, N CHANNEL JFET, SNJ132199(SOT-23)

It is marked with three digits "132". Can't seem to find any data at all
on the device.

Thanks.
 
JW wrote:

Hi all,

Looking for a datasheet or any info on a FET used in a Keithley 2000
location Q105. The service manual lists it as:
TRANS, N CHANNEL JFET, SNJ132199(SOT-23)

It is marked with three digits "132". Can't seem to find any data at all
on the device.

Thanks.
Yeah, it's tough trying to match up a JET if the pin off voltage is a
Click to expand...
critical part of the circuit. Also on top of that, it could be used as a
current source which makes it just as tricky.

I recently repaired a analog PID board that another tech repaired in
the past. They replaced the JFET switch that is in the output that
effectively turns the PID loop on/off. The way it is set in there, the
gate pinch off voltage must fall in the range of 1 to 5 volts(-) and the
tech put a NTExxx replacement in. That was a bad call. The NTE
replacement had a gate pinch off voltage of 5..10V-. This circuit only
had -5 max to play with. Needless to say, it wouldn't switch properly
50% of the time. so wee went shopping for the original replacement,
TO-92 package. guess what, I couldn't find any but I did find one that
had the Gate voltage that I needed and the Idss was even better than the
original.. So we go those. They are like gold these days!

One friendly warning, beware of using NTE parts in critical areas.
They don't always work.

Jamie
 
On Sat, 26 Nov 2011 13:45:55 -0500 Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in Message id:
<jraAq.62910$rF5.39535@newsfe19.iad>:

JW wrote:

Hi all,

Looking for a datasheet or any info on a FET used in a Keithley 2000
location Q105. The service manual lists it as:
TRANS, N CHANNEL JFET, SNJ132199(SOT-23)

It is marked with three digits "132". Can't seem to find any data at all
on the device.

Thanks.
Yeah, it's tough trying to match up a JET if the pin off voltage is a
critical part of the circuit. Also on top of that, it could be used as a
current source which makes it just as tricky.

I recently repaired a analog PID board that another tech repaired in
the past. They replaced the JFET switch that is in the output that
effectively turns the PID loop on/off. The way it is set in there, the
gate pinch off voltage must fall in the range of 1 to 5 volts(-) and the
tech put a NTExxx replacement in. That was a bad call. The NTE
replacement had a gate pinch off voltage of 5..10V-. This circuit only
had -5 max to play with. Needless to say, it wouldn't switch properly
50% of the time. so wee went shopping for the original replacement,
TO-92 package. guess what, I couldn't find any but I did find one that
had the Gate voltage that I needed and the Idss was even better than the
original.. So we go those. They are like gold these days!

One friendly warning, beware of using NTE parts in critical areas.
They don't always work.
Click to expand...
Thanks for that. I think I'll try giving Keithley a call, maybe I'll get
lucky...
 
On Sun, 27 Nov 2011 05:53:46 -0500 JW <none@dev.null> wrote in Message id:
<6k54d7lqctevfg9hee2rpjcssd44kkhkut@4ax.com>:

On Sat, 26 Nov 2011 13:45:55 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in Message id:
jraAq.62910$rF5.39535@newsfe19.iad>:

JW wrote:

Hi all,

Looking for a datasheet or any info on a FET used in a Keithley 2000
location Q105. The service manual lists it as:
TRANS, N CHANNEL JFET, SNJ132199(SOT-23)

It is marked with three digits "132". Can't seem to find any data at all
on the device.

Thanks.
Yeah, it's tough trying to match up a JET if the pin off voltage is a
critical part of the circuit. Also on top of that, it could be used as a
current source which makes it just as tricky.

I recently repaired a analog PID board that another tech repaired in
the past. They replaced the JFET switch that is in the output that
effectively turns the PID loop on/off. The way it is set in there, the
gate pinch off voltage must fall in the range of 1 to 5 volts(-) and the
tech put a NTExxx replacement in. That was a bad call. The NTE
replacement had a gate pinch off voltage of 5..10V-. This circuit only
had -5 max to play with. Needless to say, it wouldn't switch properly
50% of the time. so wee went shopping for the original replacement,
TO-92 package. guess what, I couldn't find any but I did find one that
had the Gate voltage that I needed and the Idss was even better than the
original.. So we go those. They are like gold these days!

One friendly warning, beware of using NTE parts in critical areas.
They don't always work.

Thanks for that. I think I'll try giving Keithley a call, maybe I'll get
lucky...
Click to expand...
Or not. They'll sell me the $2 part, but with a $150 minimum. They claim
this part is made to Keithley spec (!). They also offered the following
info:

"I also show that we purchased these (which were not made to KI spec)
Interfet SJN132280
Fairchild Semiconductor 5149B51374A
Fairchild Semiconductor 5149_NB51374B"

I was unable to find any datasheets or stock on any of them. *sigh*
 
JW wrote:

On Sun, 27 Nov 2011 05:53:46 -0500 JW <none@dev.null> wrote in Message id:
6k54d7lqctevfg9hee2rpjcssd44kkhkut@4ax.com>:


On Sat, 26 Nov 2011 13:45:55 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in Message id:
jraAq.62910$rF5.39535@newsfe19.iad>:


JW wrote:


Hi all,

Looking for a datasheet or any info on a FET used in a Keithley 2000
location Q105. The service manual lists it as:
TRANS, N CHANNEL JFET, SNJ132199(SOT-23)

It is marked with three digits "132". Can't seem to find any data at all
on the device.

Thanks.

Yeah, it's tough trying to match up a JET if the pin off voltage is a
critical part of the circuit. Also on top of that, it could be used as a
current source which makes it just as tricky.

I recently repaired a analog PID board that another tech repaired in
the past. They replaced the JFET switch that is in the output that
effectively turns the PID loop on/off. The way it is set in there, the
gate pinch off voltage must fall in the range of 1 to 5 volts(-) and the
tech put a NTExxx replacement in. That was a bad call. The NTE
replacement had a gate pinch off voltage of 5..10V-. This circuit only
had -5 max to play with. Needless to say, it wouldn't switch properly
50% of the time. so wee went shopping for the original replacement,
TO-92 package. guess what, I couldn't find any but I did find one that
had the Gate voltage that I needed and the Idss was even better than the
original.. So we go those. They are like gold these days!

One friendly warning, beware of using NTE parts in critical areas.
They don't always work.

Thanks for that. I think I'll try giving Keithley a call, maybe I'll get
lucky...


Or not. They'll sell me the $2 part, but with a $150 minimum. They claim
this part is made to Keithley spec (!). They also offered the following
info:

"I also show that we purchased these (which were not made to KI spec)
Interfet SJN132280
Fairchild Semiconductor 5149B51374A
Fairchild Semiconductor 5149_NB51374B"

I was unable to find any datasheets or stock on any of them. *sigh*

More than likely a standard fet in fairchild list of JFETS with a custom
Click to expand...
number on it for them. This is done very often to force you to
use their service centers or to force you to buy new from them. However,
buying new would mean they have a good product! :)

THe last company I can remember that made custom things for their
products were people like Tektronics and I know there are a slew of
others that do that for undisclosed customers.

If you had a schematic with voltages and basic functions as to what
it does, it would be easy to come up with a replacement.

Jamie
 
JW <none@dev.null> wrote:
On Sun, 27 Nov 2011 05:53:46 -0500 JW <none@dev.null> wrote in Message id:
6k54d7lqctevfg9hee2rpjcssd44kkhkut@4ax.com>:

On Sat, 26 Nov 2011 13:45:55 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in Message id:
jraAq.62910$rF5.39535@newsfe19.iad>:

JW wrote:

Hi all,

Looking for a datasheet or any info on a FET used in a Keithley 2000
location Q105. The service manual lists it as:
TRANS, N CHANNEL JFET, SNJ132199(SOT-23)

It is marked with three digits "132". Can't seem to find any data at all
on the device.

Thanks.
Yeah, it's tough trying to match up a JET if the pin off voltage is a
critical part of the circuit. Also on top of that, it could be used as a
current source which makes it just as tricky.

I recently repaired a analog PID board that another tech repaired in
the past. They replaced the JFET switch that is in the output that
effectively turns the PID loop on/off. The way it is set in there, the
gate pinch off voltage must fall in the range of 1 to 5 volts(-) and the
tech put a NTExxx replacement in. That was a bad call. The NTE
replacement had a gate pinch off voltage of 5..10V-. This circuit only
had -5 max to play with. Needless to say, it wouldn't switch properly
50% of the time. so wee went shopping for the original replacement,
TO-92 package. guess what, I couldn't find any but I did find one that
had the Gate voltage that I needed and the Idss was even better than the
original.. So we go those. They are like gold these days!

One friendly warning, beware of using NTE parts in critical areas.
They don't always work.

Thanks for that. I think I'll try giving Keithley a call, maybe I'll get
lucky...

Or not. They'll sell me the $2 part, but with a $150 minimum. They claim
this part is made to Keithley spec (!). They also offered the following
info:
Click to expand...
haha, what assholes.
 
On 11/26/2011 7:51 AM, JW wrote:
Hi all,

Looking for a datasheet or any info on a FET used in a Keithley 2000
location Q105. The service manual lists it as:
TRANS, N CHANNEL JFET, SNJ132199(SOT-23)

It is marked with three digits "132". Can't seem to find any data at all
on the device.

Thanks.
Click to expand...
Wild guess

Interfet IF1320?

JC
 
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