I really like the ITT 400E cards. I've only had a couple fail. Both times it was bad diodes. Nothing special, just your garden variety 1N400x type. I keep a bucket of 1N4007's around so I just swapped them with those. They work just ducky.

They don't have that stupid thing of some western electric cards where they only ring up on grounded ringing (like pre issue 15 400D's) or some of the wackyness of the later WECO 400 cards. I had some 400H's that if you quickly pressed the hold button and released it (LIKE ANYONE NORMALLY WOULD) it would drop the call. You had to keep the hold button depressed for a solid second or more to reliably hold the call. They've since been sitting on a shelf for 5 years. I like the issue 15 400D's. 5 of my 6 line cards are currently those. They work wonderfully. Someone at the Lancaster TCI show a couple years ago had a 1A2 rack with like 5 or 6 loaded 584 panels and I asked if he'd sell some of the line cards. He said sure, so I picked out all the Iss 15 400D's. I doubt I paid him more than a few dollars a piece for them.