So, my first EM restoration attempt and - as is usual - uncovering lots of odd adaptations and workarounds by previous generations of owners and operators.
Now that I have stripped down all four pop bumpers, a question immediate arises for me in the difference between the pop bumper switches.
In my understanding pop bumpers of this era had two switches - the usual cup switch which causes a relay to energise. Some contacts on that relay form a holding ciruit and others energise the bumper coil.
When the coil is fully energised, another switch opens and breaks the hold circuit on the relay and thus the coil de-energises. Is that about right?
Anyway my question is why - on this machine - does only one of the bumpers have what looks like a viable set of holding contacts (photo 2)? The others are either just one leaf left of that switch, or the wires removed.
How is the relay holding cct broken in this case - the pop bumpers were working fine - even though the plastics were all held together with glue and hope! (Thus my need to replace all the plastics).
Now that I have stripped down all four pop bumpers, a question immediate arises for me in the difference between the pop bumper switches.
In my understanding pop bumpers of this era had two switches - the usual cup switch which causes a relay to energise. Some contacts on that relay form a holding ciruit and others energise the bumper coil.
When the coil is fully energised, another switch opens and breaks the hold circuit on the relay and thus the coil de-energises. Is that about right?
Anyway my question is why - on this machine - does only one of the bumpers have what looks like a viable set of holding contacts (photo 2)? The others are either just one leaf left of that switch, or the wires removed.
How is the relay holding cct broken in this case - the pop bumpers were working fine - even though the plastics were all held together with glue and hope! (Thus my need to replace all the plastics).
