Well you've achieved (stumbled on) a cure so all is well.
Did you make a note of the different resonance points? This can help
indicate the different capacity specs.
e.g. crystals have been spec'd for 30pF, or 20pF, or 12pF, at different
times and for different equipments.
Crystals that get "tired" can play up again so the info might help you then.
Peter
-----Opprinnelig melding-----
Fra: Paul Kraemer [mailto:elespe@lisco.com]
Sendt: 20. juli 2009 05:05
Til: Peter - LC0TC
Emne: Re: [Yaesu] part needed
Peter
Yes, the original crystals resonated significantly different than the new
ones I had tried.
I was able to get the new ones correct by adding 10pf capacity but this
messed up the range of the padder corrector capacitor.
In the end, after swapping parts between the two oscilllators, to no avail,
and re-soldering all the connections in the circuit even though they
appeared fine, I tried the original crystal and now it is perfect.
Must have been a connection?
Go figure.
Paul
----- Original Message -----
From: "Peter - LC0TC" <peter.lc0tc@combitel.no>
To: "Paul Kraemer" <elespe@lisco.com>; <yaesu@contesting.com>
Sent: Sunday, July 19, 2009 7:44 AM
Subject: SV: [Yaesu] part needed
> Is it possible that the standard crystals are made to a different (wider?)
> specification and .have another parallell capacity than that type used by
> Yaesu?
>
> Peter LB0K
>
>
> -----Opprinnelig melding-----
> Fra: yaesu-bounces@contesting.com [mailto:yaesu-bounces@contesting.com]Pa
> vegne av Paul Kraemer
> Sendt: 14. juli 2009 21:21
> Til: yaesu@contesting.com
> Emne: [Yaesu] part needed
>
> Need part 71800106 HC-18/U 18.0MHz xtal #210045-1
> Used in FT-901 counter unit
> Have tried "off the shelf" 18 MHz crystals from Mouser and DigiKey
> The frequency is correct but they cannot be moved by the corrector
> variable
> cap in the circuit
> Am I missing something???
> Paul K0UYA
>
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