Replacement 5V crystal arrived today. Extremely fast dispatch but its output is only 1.2Vpp and nowhere near the expected TTL level!
I modeled satbegginers idea in LTSpice but couldn't get it to work properly. The output was barely above zero. Scm's idea works well enough though provided NPN collector goes to Vcc and PNP collector goes to ground! I used 2N2222 for the NPN (transition frequency=250MHz) and 2N2907 for the PNP (transition frequency=200MHz).
