Hi Geoff
Nothing out of IC551 pins 25 and 26 which feed IC601 , ic601 is underneath so very hard to get to but checked on ic551 pins 25 and 26 and nothing at all with a good clean signal on pin 4. i haven't checked pin 13 on 551 yet but will try and get to it by the end of the week. Also thinking about ordering another chip to replace ic551 - they are relatively cheap and worth a shot. If it doesn't fix the problem then the issue lies somewhere else
James
