Yep, which U24 as a 74HC14 chip has the simple job of inverting - except right now all it (seems) to be doing is flatlining it. The correct usually-low, pulsing-high signal is going into U24 and we should see the pulsing-low signal coming out
ok i have checked and triple checked the voltage at pin 14 (5.02v perfect smooth line) and the ground at pin 7 which is a good low resistance connection, i have removed the board and sandpapered the rust off the mounts and groundplane. i have lowered the resistance across the grounds to near enough 0.2 ohms after allowing for the test leads.
to make sure i have also checked the other 5 'not' gates on the same IC and while none of them are oscillating, they are all doing what they should be (low input is a high output and vice versa)
so i have placed an order with farnell for 2 new IC's and 2 sockets. should be here tomorrow according to their website. as soon as they turn up i will get them thrown in and give you the good (hopefully) news
