Bruce,
If you were building a replacement for one of these delay relays (hypothetically speaking, maybe for a 533A), would it be enough to have a timer that cut a relay in after a fixed time? Is that really all that the delay relay is doing?
Might there be another way to determine when the heaters are at temperature, like by monitoring the current through the heaters, or even by directly sensing the temperature of the tubes themselves?
Just curious (though I am in the process of refurbing a 533A, and this may be useful information when I get to the point of applying power to the instrument)
-- Jeff Dutky
