Hi Folks
I have a FPM-300 with a few dead xtals. I can order the xtals but I have
no clue about the designation of the mount or the pf/ohm of the xtal.

The manual has part numbers but none of the other information. (see below)

As far as the size, the manual describes needing a "type CR-55A/U or
CR-72/U for HC-18/U holder" but http://jancrystals.com/chart.html and
others only describe other specs (HC25 plugin can) that appear to be the
same size.

How wrong could I be in ordering a xtal that physically looks right at
the proper freq?


CR405 43.0Mhz 019-04749
CR406 43.5Mhz 019-04751
CR407 44.0Mhz 019-04752

In article ,
No Spam wrote:

Hi Folks
I have a FPM-300 with a few dead xtals. I can order the xtals but I have
no clue about the designation of the mount or the pf/ohm of the xtal.

The manual has part numbers but none of the other information. (see below)

As far as the size, the manual describes needing a "type CR-55A/U or
CR-72/U for HC-18/U holder" but http://jancrystals.com/chart.html and
others only describe other specs (HC25 plugin can) that appear to be the
same size.

How wrong could I be in ordering a xtal that physically looks right at
the proper freq?


CR405 43.0Mhz 019-04749
CR406 43.5Mhz 019-04751
CR407 44.0Mhz 019-04752

NS-

Holders that look similar may have different pin spacing and/or
diameter. In addition, the crystal must match the circuit it is used
in. Choices may include impedance, whether it is series or parallel
resonant at the specified frequency, and load capacitance of the circuit.

Crystal manufacturers often have a collection of data for equipment for
which they have provided crystals. You need to talk to someone at the
manufacturer to find if they have crystal data for your specific
equipment. If not, you must provide the crystal's circuit diagram so
they can determine the necessary parameters.

Jan Crystals has been around for a long time, so may have your crystal
data in their files. International Crystal and Bliley Technologies are
also older companies that may have extensive data.

Fred
K4DII

No Spam wrote:
Hi Folks
I have a FPM-300 with a few dead xtals. I can order the xtals but I have
no clue about the designation of the mount or the pf/ohm of the xtal.

The manual has part numbers but none of the other information. (see below)

As far as the size, the manual describes needing a "type CR-55A/U or
CR-72/U for HC-18/U holder" but http://jancrystals.com/chart.html and
others only describe other specs (HC25 plugin can) that appear to be the
same size.

If you call up ICM or JAN, they will almost certainly have the required
specs in the book and they can tell you exactly what you need. Expect
to pay $20 each or so.

How wrong could I be in ordering a xtal that physically looks right at
the proper freq?

If it's designed for different load capacitance, it won't be right on
frequency. For an application like this, that's not critical but it
might require a little tweaking. Just call them up and they'll know
how to do it precisely.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."