I've Googled till I'm blue, but I haven't been able to find it.  What
 would be a good cross for a DEC 3639 PNP transistor?  Or, failing   
Most fo the time, for transistors, you replace 'DEC' with '2N'. Would a
2N3639 make any sense in the circuit (is it the same polarity, same
package, etc?)
-tony