(subj: Need Source for Diode in TS-1285/URM-120 Wattmeter 2-30 MHz Plug-in
Sensor)

Hi, all concerned:

The diode looks like a 1N23-type, with cathode (arrow) toward tip.

Has marking ALPHA D4190A.

TIA & 73,

Dave, N3HE

....
(subj: Need Source for Diode in TS-1285/URM-120 Wattmeter 2-30 MHz Plug-in
Sensor)

Hi, all concerned:

The diode looks like a 1N23-type, with cathode (arrow) toward tip.

Has marking ALPHA D4190A.

TIA & 73,

Dave, N3HE

The book on mine only lists a parts assymble. From an artical in QST May
1996 it states 'it looks like a 1N21 or 1N23 but something is differant. If
replaced with a 1N21 the lowest third of each scale is unusable.'
The author states that a Wetern Electric GA50649 and dated 2/59 is a usuable
replacement.
I think the diodes were selected for each specific meter.

In another artical in September 1996 they are Sierra part numbers
SS-13154-1-n where the n is a specific digit that identifies the specific
plug-in. Sierra also made a version of the watt meter. They were selected
1N21s but you need a bunch of them to select the correct one that will work
in a specific meter.

A company called Struthers also made a version of the meter.

I can not verify any of this info above but just reporting from the
articals.

I have the Struthers version and it has a knob on it for SWR. Lucked out at
a hamfest and found one still in the origional packing box that had never
been opened from the time it was calibrated in 1983. It came with 3 plug
ins for 3 to 1000 mhz and dthe manual but the book does not list the diode
by its self, just an unreconisonable asymble.

....
(subj: Need Source for Diode in TS-1285/URM-120 Wattmeter 2-30 MHz Plug-in
Sensor)

Hi, all concerned:

The diode looks like a 1N23-type, with cathode (arrow) toward tip.

Has marking ALPHA D4190A.

TIA & 73,

Dave, N3HE

The book on mine only lists a parts assymble. From an artical in QST May
1996 it states 'it looks like a 1N21 or 1N23 but something is differant. If
replaced with a 1N21 the lowest third of each scale is unusable.'
The author states that a Wetern Electric GA50649 and dated 2/59 is a usuable
replacement.
I think the diodes were selected for each specific meter.

In another artical in September 1996 they are Sierra part numbers
SS-13154-1-n where the n is a specific digit that identifies the specific
plug-in. Sierra also made a version of the watt meter. They were selected
1N21s but you need a bunch of them to select the correct one that will work
in a specific meter.

A company called Struthers also made a version of the meter.

I can not verify any of this info above but just reporting from the
articals.

I have the Struthers version and it has a knob on it for SWR. Lucked out at
a hamfest and found one still in the origional packing box that had never
been opened from the time it was calibrated in 1983. It came with 3 plug
ins for 3 to 1000 mhz and dthe manual but the book does not list the diode
by its self, just an unreconisonable asymble.

David J. Windisch wrote:
(subj: Need Source for Diode in TS-1285/URM-120 Wattmeter 2-30 MHz Plug-in
Sensor)

Hi, all concerned:

The diode looks like a 1N23-type, with cathode (arrow) toward tip.

Has marking ALPHA D4190A.

TIA & 73,

Dave, N3HE



The Sierra manual claims it's a silicon diode
Bomac BL-161.
mike


--
Bunch of stuff For Sale and Wanted at the link below.
21' RV, 400cc Dirt Bike
Police Scanner, LCD overhead projector
Tek 2465, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

David J. Windisch wrote:
(subj: Need Source for Diode in TS-1285/URM-120 Wattmeter 2-30 MHz Plug-in
Sensor)

Hi, all concerned:

The diode looks like a 1N23-type, with cathode (arrow) toward tip.

Has marking ALPHA D4190A.

TIA & 73,

Dave, N3HE



The Sierra manual claims it's a silicon diode
Bomac BL-161.
mike


--
Bunch of stuff For Sale and Wanted at the link below.
21' RV, 400cc Dirt Bike
Police Scanner, LCD overhead projector
Tek 2465, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

mike wrote:
David J. Windisch wrote:

(subj: Need Source for Diode in TS-1285/URM-120 Wattmeter 2-30 MHz
Plug-in
Sensor)

Hi, all concerned:

The diode looks like a 1N23-type, with cathode (arrow) toward tip.

Has marking ALPHA D4190A.

TIA & 73,

Dave, N3HE



The Sierra manual claims it's a silicon diode
Bomac BL-161.
mike


It is simply a 1N21 which has been selected so that the meter will read
full scale on the lowest range of the plug-in. I have found a suitable
replacement for one of my plug-ins by trying a number of diodes until a
full scale reading could be achieved. This will require recalibration
of the plug-in, which is not a trivial task, unless the wattmeter reads
correctly for a known power source.

Do not forget to wrap the diode with tape, per the instruction manual.

Bob, W6NBI

mike wrote:
David J. Windisch wrote:

(subj: Need Source for Diode in TS-1285/URM-120 Wattmeter 2-30 MHz
Plug-in
Sensor)

Hi, all concerned:

The diode looks like a 1N23-type, with cathode (arrow) toward tip.

Has marking ALPHA D4190A.

TIA & 73,

Dave, N3HE



The Sierra manual claims it's a silicon diode
Bomac BL-161.
mike


It is simply a 1N21 which has been selected so that the meter will read
full scale on the lowest range of the plug-in. I have found a suitable
replacement for one of my plug-ins by trying a number of diodes until a
full scale reading could be achieved. This will require recalibration
of the plug-in, which is not a trivial task, unless the wattmeter reads
correctly for a known power source.

Do not forget to wrap the diode with tape, per the instruction manual.

Bob, W6NBI