Need help resurrecting an old Dynacord EC280 BBD Delay

[drolo]

I have had this great delay lying around dead on my bench for a couple of years now, never finding the courage to debug it.
It was working fine when I bought it but stopped all of a sudden.

I only get dry signal and no delay anymore.

These last weeks, I decided to dive into it (and at the same time learn a bit about BBD's which I have never worked with)

This is a link to the schematic: http://www.davidrolo.com/wp-content/uploads/2014/05/EC_280_Schematic.pdf

Power Supply is working fine. All chips are powered.
I traced the signal up to the input of the first BBD (TDA1022), but no output from that BBD. I tried swapping around a few BBD's but still no output. I can't imagine that all of the BBD's suddenly died..

If I understood correctly, the MC14011 is responsible for the BBD's clock. I hooked up my MM to measure the frequency at its output but don't read anything.
My MM can measure up to 10MHz, from what I understood from the datasheet, the TDA1022 is rated for a clock from 5 – 500KHz. So my MM should be reading it.

Here is the section showing the clock:



Would a missing clock result in the BBD presenting no output?
If yes, I will try to replace the MC14011 (and perhaps the MC14027 and MC14049 as well)

There is also a CA3080 responsible for varying the clock that the MC14011 generates. I measured that its output increases when I turn up the speed button, so this should mean that it is working correctly?

Am I on the right track?

Any pointers or tips will be very welcome.

[Scruffie]

If the BBD has no clock, it will not work so you are right to suspect the 4011, 4027 & 4049, CMOS chips like that are static sensitive so they certainly do die and with no clock pulse being generated by them, looks like you have your answer 

[drolo]

If the BBD has no clock, it will not work so you are right to suspect the 4011, 4027 & 4049, CMOS chips like that are static sensitive so they certainly do die and with no clock pulse being generated by them, looks like you have your answer 

I ordered the chips and am patiently waiting by the mailbox :-)