I had the same problem: the NO-OD light would glow lightly, and I would occasionally not get OD (it never droped out, just wouldn't go all the way up, sometimes). I had all sorts of plans (swap, manual conversion, rebuild) but the were all out of ignorance.

I pulled the relay out and took it to my bench, cracked it open, and strated cleaning up solder joints on the printed circut board. Don't know if I did any good, but I haven't had the problem since (2 years ago).

Apparently, these relays over-heat and the solder used to make them was less then the highest quality. Repairing them is just as easy as finding a faulty one in a junkyard.

In short: I wouldn't trust it unless you test it.

--Aubrey