In article ,
Rory wrote:
ust thought I'd update this - I limped along with my original PCB. I
had tried prodding it - a plastic baby spoon worked well! - and found
two of the relays clicked when nudged, so a bit of gentle 'packing'
helped them work.

That suggests a dry joint somewhere - or a broken track which makes when
flexed.

My first approach would be to remove the board and re-flow all the joints.

If it is a multi layer PCB, make sure any through hole stuff flows to both
sides.

--
*Change is inevitable, except from a vending machine*

Dave Plowman London SW
To e-mail, change noise into sound.