R_Lyle said:
What I worry about with the A-type is the solonoid switch which is so expensive to replace.
Huh? You lost me there; the J-type solenoid is more than twice the price of the A-type! See for example
https://www.zeni.net/trf/TR6-250GC/158.php
That's reasonable of course, as the J-type soleoid is more complicated (it includes a hydraulic valve while the A-type is just a solenoid).
BTW, I feel it's a worthwhile modification to add a fuse to the circuit for the A-type, to protect the solenoid in case it hangs up for some reason and the contacts don't open.
A-type solenoids have two coils internally, the holding coil only draws about an amp and can run forever; but the pull-in coil draws about 20 amps and normally is only energized for an instant. When the plunger reaches it's final position, it pushes against some internal contacts that open the circuit to the pull-in coil. If the plunger hangs up for some reason, or the little plastic pushrod for the contacts breaks or falls out; the pull-in coil will quickly overheat. By using a fuse smaller than 20 amps, the fuse will blow first and offer at least the potential for fixing the problem with the solenoid.
Stags actually came with such a fuse, but TRs did not. On my 3A, I used an 8 amp "slo-blo" just because that's what I had on hand, but I believe an ordinary 5 or 10 amp fuse would do fine.