Hey guys, it's the new guy...again. Thanks for the help again. Out of the 4 400e cards I have in my 551b, 2 work perfectly and 2 have totally opposite problems. One will not go on hold at all in any position in the KSU. It was in the 4th line slot which is unused so I didn't realize it until I swapped it for the other card that goes on hold whenever the line is terminated. It does ok at first, but gets worse as the unit is used. I can get it to terminate if I slowly depress the hook switch. I also hear almost a double relay click when it's acting up. The problem also follows the card in differed positions. I ordered 4 400h cards (found a smoking deal), but should I bother to diagnose and repair them, or just toss them? Also, is the itt card of equal quality and reliability? Thanks again.

Just for kicks, try these with a different phone if you have one. Usually these kind of hold issues lie with the hook switch in the phone. There are 2 sets of contacts that must make and break in a carefully timed sequence. If they are out of whack, false holds are the usual result. Then again, you may simply have 2 line cards that gave up the ghost.

** I have a mix of ITT and WECO line cards in my ksu and both work flawlessly. There are some cards to stay away from, but I'll leave that to a member with more experience to tell you which ones.

400 series cards of all manufacturers just worked.......till they didn't.

To be honest, if we had a bad card we just tossed it, but they didn't go bad too often. Of course, all these cards are now all at least 30 or 40 years old, so really - what do you expect?

We never used WECO cards. Depending who I was working for, it was either ITT, AE, Sanbar or ........whatever. I never had a problem with any of them.

Sam

Most probably, dried up capacitors, tired relays and, if the card has an op-amp, the op-amp are sources for failure. Just as Sam said, "what do you expect for 30-40 year old electronics?"

Rcaman

Just to clarify my last post - We did not use WECO cards because they were not available to us, not because of quality issues. WECO was well known for their quality. But if you weren't a Bell Operating Company it was difficult, if not illegal to get Western Electric material.

Sam

Could the cards that are configured differently (different modifications) result in the described linecard problem described with a 551B? Yes, linecards are less than eight bucks on ebay, but I'm curious if that could make the difference.

Line cards are available for a few bucks apiece, if you ask the right people. Check Ebay periodically. I suggest that you use SanBar 4000F cards, which are the ones that Bell used when their own 400-series were either failing or not available.

Just toss the ones you have and replace them.