I have been thinking about Paul's symptoms. If he has lost current on the bias winding, that would leave the bistable relay stuck in the marking position.

If the relay passes the bench test. He could  use Ohm's law to rough out the voltage on the 30 mil and 60 mil windings and try to measure it with the relay in circuit. If there is no bias it comes down to troubleshooting. I would make sure the power supply is working first then start tracing backwards from the relay. If there is a bias current test jack make sure the shorting contact is closing.

Tom  N3CRK