Hi Stephen and thanks for the reply.

>The burden capacitors belong to the crystal and not to the processor. What happens when you use a sensible burden cap, like a 22pF ?

It swamps the oscillator voltage down too low - about 200mVpp.

>What is the crystal spec ? At 24 Meg are you using an overtone crystal ?

Fundamental mode, AT-Cut, 18pF (yes this is the normal loading cap value I use for these crystals for optimal accuracy), HC-49 package. CTS is the manufacturer of this one, also have other on hand with similar specs.

I'm not aware of any 5pF crystals. I agree with everything that Kai said in the post you pointed to. It's basic oscillator theory, but seems to be left out of most of the data sheets.

Thanks again
Trev