CEM 3340 chip problems

[Chris Christensen]

Greetings,

	I recently purchased a batch of CEM 3340 VCO chips from OnChip.  
I have been testing the chips in a breadboard circuit. Some of the 
chips   function perfectly but some seem to have problems. Some exhibit 
non-periodic oscillation (noise) at some frequencies which varies as I 
touch certain places in the circuit.  I can fix some of the problem by 
adding a small capacitor from pin 10 or pin 15 to ground.(?)   

	Are these chips sensitive to stray capacitance or are they 
defective. I have heard that these chips have not been  tested but I am 
surprised that so many seem to have problems. Has  anyone 
else had problems with these chips?  Is the circuit layout I use for 
testing  the chips critical? 

Thanks for any help,
Chris <cchris at hooked.net>