atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 1a2

after storm line goes to hold when hanging up. Already changed line card. same condition on all phones on line 1

Sounds like the A-Lead is open. Does your card work in another slot? If so, check your KSU wiring. The A-Lead on the KSU block should be the the 3rd pair (Wh/Grn).

The A lead is on the second pair, as in the tip side of the white/orange pair, but that is beside the point. What version of line cards do you have?

Are they all the same brand/model/version? Do things behave on the other line(s) on the system? Help us help you.

Do incoming calls on Line 1 come through OK?

Have you checked EVERY telephone on the system to ensure that one of them (1) does not have Line 1 pressed, and (2) is not "almost" on-hook?

You say that you changed the card. Did you use a spare card that was sitting in the dust on the shelf, or did you use a known-working one from another slot in the KSU?

Does the line lamp come on normally, when any station goes off-hook on line 1?

Does line 1 go on Hold normally, when the Hold button is pressed?

If you mechanically pop up the Line 1 button, (by pressing another line button) while in use, rather than placing the handset on hook, does the line go on false Hold?

Sounds like you have a high-resistant short circuit on the STATION T&R leaving the KSU. Maybe moisture, maybe a shorted ringing capacitor, maybe a lightning-struck phone.

You need to remove the line card and using an analog ohmmeter, check for resistance on the STATION T&R (white/blue - blue/white pair) going to each station. With the card out, you should see a kick, if there are bridged ringers, and then the meter should settle at infinity. Any significant reading above infinity indicates a short circuit on T&R, which will cause a false Hold condition.

For the benefit of all of our friends on the Forum, placing a call on Hold in 1A2 requires a very carefully-timed sequence of events:

Hold a call: The A lead must go OPEN just before the STATION T&R goes OPEN.

End a call: The T&R must go OPEN before the A-lead goes OPEN.

Both the line key and SWHK contact pile-ups are designed to open the T&R just before the A lead goes open. If they are out of adjustment, you get a false Hold condition.

When ending a call, if the line card sees a significant current draw on T&R, (caused by a S/C or high capacitance on T&R ... too many bridged ringers after the line card, for instance...) as the A lead goes open it will place the call on false Hold.

Actually, you're both right.

In the standard cut-down of a 584C panel, the first five pairs, and all subsequent groups of five pairs, are:

T&R CO
T&R STA
A-A1
LG-L
GRD-CMB

So, the third pair (x-Gr/Gr-x) is the A leads.

In a 501 or 551 KSU, the cut-down at the KSU block follows the color code of the mounting cord:

T&R STA
A-A1
LG-L

So, the second pair (white-orange/orange-white) is the A leads.

Any chance one of your 25pr cables is WET?

The OP said it happens on all phones so I was adressing the card's A-Lead and not the station's.

Actually, I would just manually test the line at the KSU with a butt set and a screwdriver working the A-Lead. Arthur has spelled out the sequence of events very nicely. You might also find it helpful to disconnect the station cross connect wiring first and then go from there.

I just heard from the OP that the pairs going to an extension in an outbuilding were the culprit. He didn't say exactly, but we assume it was a S/C on the 1st line T&R.

Arthur, S/C? (I know I'm gonna do a forehead smack)