Transistor identification help (HP3457A)
 

I have a TO-92 Motorola transistor that I've been unable to identify. It
markings a
______
| 4-|
| 094|
|m913|
-----
The m in the above pic is the Motorola logo.

It's out of a HP 3457A DMM. Unfortunately, none of the service manuals
that I've downloaded has the schematic or parts list of this particular
revision of the circuit board. It located on the analog portion of the
meter and is part of the optically coupled serial interface to the digital
section.

Thanks for any help!

Transistor identification help (HP3457A)
 

JW wrote:

I have a TO-92 Motorola transistor that I've been unable to identify.

How do you know it's a transistor ?

Graham

Transistor identification help (HP3457A)
 

On Fri, 18 May 2007 09:48:13 GMT Eeyore
wrote in Message id:
:



JW wrote:

I have a TO-92 Motorola transistor that I've been unable to identify.

How do you know it's a transistor ?

Assuming. I, of course, could be wrong...
The device is shorted, so I can't test it to be sure. Of course it's the
only one in the whole meter, otherwise I could have extracted another for
testing.

Transistor identification help (HP3457A)
 

They appear to be HP numbers.
The 4- is the end of 1854-xxxx. Don't know about the rest. I have a pdf file of
cross references if you want it? email me direct.

Colin
"JW" wrote in message
...
I have a TO-92 Motorola transistor that I've been unable to identify. It
markings a
______
| 4-|
| 094|
|m913|
-----
The m in the above pic is the Motorola logo.

It's out of a HP 3457A DMM. Unfortunately, none of the service manuals
that I've downloaded has the schematic or parts list of this particular
revision of the circuit board. It located on the analog portion of the
meter and is part of the optically coupled serial interface to the digital
section.

Thanks for any help!

Transistor identification help (HP3457A)
 

On the circuit board is there a reference designator for the part
(Q123 for example) ?

On May 18, 5:21 am, JW wrote:
I have a TO-92 Motorola transistor that I've been unable to identify. It
markings a
______
| 4-|
| 094|
|m913|
-----
The m in the above pic is the Motorola logo.

It's out of a HP 3457A DMM. Unfortunately, none of the service manuals
that I've downloaded has the schematic or parts list of this particular
revision of the circuit board. It located on the analog portion of the
meter and is part of the optically coupled serial interface to the digital
section.

Thanks for any help!

Transistor identification help (HP3457A)
 

Colin Horsley wrote:
They appear to be HP numbers.
The 4- is the end of 1854-xxxx. Don't know about the rest. I have a pdf file of
cross references if you want it? email me direct.

Colin
"JW" wrote in message
...
I have a TO-92 Motorola transistor that I've been unable to identify. It
markings a
______
| 4-|
| 094|
|m913|
-----
The m in the above pic is the Motorola logo.

It's out of a HP 3457A DMM. Unfortunately, none of the service manuals
that I've downloaded has the schematic or parts list of this particular
revision of the circuit board. It located on the analog portion of the
meter and is part of the optically coupled serial interface to the digital
section.

Thanks for any help!





I have a cross reference that says (if the above is true) that it is
1854-0094 = MPS3646 Don't know if this is even similar, but just
thought I would throw it out there.

Transistor identification help (HP3457A)
 

On Fri, 18 May 2007 12:43:41 GMT Ken wrote in
Message id: :

Colin Horsley wrote:
They appear to be HP numbers.
The 4- is the end of 1854-xxxx. Don't know about the rest. I have a pdf file of
cross references if you want it? email me direct.

Colin
"JW" wrote in message
...
I have a TO-92 Motorola transistor that I've been unable to identify. It
markings a
______
| 4-|
| 094|
|m913|
-----
The m in the above pic is the Motorola logo.

It's out of a HP 3457A DMM. Unfortunately, none of the service manuals
that I've downloaded has the schematic or parts list of this particular
revision of the circuit board. It located on the analog portion of the
meter and is part of the optically coupled serial interface to the digital
section.

Thanks for any help!





I have a cross reference that says (if the above is true) that it is
1854-0094 = MPS3646 Don't know if this is even similar, but just
thought I would throw it out there.

Bingo! That was it. Meter is up and running again. Thanks everybody for
all your help, and thank you Colin for those cross refs - they will prove
to be quite valuable, I'm sure!