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Umm, a "lazy" 10.24 MHz crystal that's slow to start up?

Kinda far out there, but if you have a way to "sniff" for this crystal's signal, it's worth a look.

More than once I have accidentally "awakened" a lazy slow-starting crystal by poking one side of it with a 'scope probe while looking for that signal. A radio that just magically comes back to life when you poke a crystal circuit with a 'scope probe points to trouble in that circuit, whether or not the crystal itself is the culprit.

Now I just listen for it with a service monitor or any handy receiver that covers that frequency. Don't have to touch any part of the circuit to do that. The 'scope probe becomes an antenna if you hold it a half-inch from the crystal.

For that matter, checking the 5-Volt supply pin on the PLL chip would be a good idea. If that voltage is low, wacky things can happen.

73

<blockquote data-quote="nomadradio" data-source="post: 659723" data-attributes="member: 22">Umm, a &quot;lazy&quot; 10.24 MHz crystal that&#039;s slow to start up?Kinda far out there, but if you have a way to &quot;sniff&quot; for this crystal&#039;s signal, it&#039;s worth a look.More than once I have accidentally &quot;awakened&quot; a lazy slow-starting crystal by poking one side of it with a &#039;scope probe while looking for that signal. A radio that just magically comes back to life when you poke a crystal circuit with a &#039;scope probe points to trouble in that circuit, whether or not the crystal itself is the culprit.Now I just listen for it with a service monitor or any handy receiver that covers that frequency. Don&#039;t have to touch any part of the circuit to do that. The &#039;scope probe becomes an antenna if you hold it a half-inch from the crystal. For that matter, checking the 5-Volt supply pin on the PLL chip would be a good idea. If that voltage is low, wacky things can happen.73</blockquote>

[QUOTE="nomadradio, post: 659723, member: 22"] Umm, a "lazy" 10.24 MHz crystal that's slow to start up? Kinda far out there, but if you have a way to "sniff" for this crystal's signal, it's worth a look. More than once I have accidentally "awakened" a lazy slow-starting crystal by poking one side of it with a 'scope probe while looking for that signal. A radio that just magically comes back to life when you poke a crystal circuit with a 'scope probe points to trouble in that circuit, whether or not the crystal itself is the culprit. Now I just listen for it with a service monitor or any handy receiver that covers that frequency. Don't have to touch any part of the circuit to do that. The 'scope probe becomes an antenna if you hold it a half-inch from the crystal. For that matter, checking the 5-Volt supply pin on the PLL chip would be a good idea. If that voltage is low, wacky things can happen. 73 [/QUOTE]

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