Bush TR82C.

[Robert Darwent]

mains droppers where a section had gone open circuit and then bridged with a replacement dropper section only to find that the original section had remade it's contact

Yes if it were a mains dropper Lawrence, then safety becomes the prime concern and you would remove the faulty section without question - but it is a small signal diode we are talking about here.

If the old detector is left in circuit and it fails short circuit it is inconvenient but not fatal. It is a compromise to me

Let's consider the two failure extremes with this detector diode.

If it's failed open-circuit, then it has already taken itself out of the signal pathway and soldering a replacement underneath or inside the IFT is the same either way and you have saved yourself the hassle of removing the IFT can.

If it's failed short-circuit, then soldering a replacement underneath is going to make no difference to the existing fault condition as the new diode will be bypassed by the short. But at least you would now know the IFT can needs removing for definite.

If the detecor diode has failed in some other intermediate fashion, then adding a replacement underneath will either solve the problem or it won't. If it does solve it - again you have saved yourself the hassle of removing the IFT can.

There is no compromise I can see by adding a diode underneath in the first instance. It will either solve the problem or tell you for definite you need to remove the IFT can.

It's a bit of a faff to remove IFT3 as you have a few connections to disturb... You also need to exercise care when replacing the diode that you don't break any of the fine wires of the IFT windings.

As pointed out by David earlier in this thread, you risk damaging the fine wires inside the IFT by opening it. Remember, Laurie who will be carrying out this work is a self-confessed beginner and may not feel confident to safely open a delicate IFT as the rest of us might.

Regards