atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems ITT 501C Intercom

Matt:

The buzzers with red leads are for 18 volts; the ones with blue leads are for 10. Obviously, the life span of the 10 volt buzzers will be shortened if used with 18 volts.

The relays on the card form a matrix, almost the same matrix formed by a DTMF dial. For each digit dialed, a different combination of relays are activated. That's probably why you see something from two different digits when you are testing. You should see two separate relays operate for any digit dialed. The fact that you are getting the same response leads me to believe that the card is not bad.

It's not possible for an "out of tune" dial to cause the problem that you are having. If half of a DTMF digit isn't produced, then nothing will register.

You are very, very close to solving this. I am sure that the whole problem revolves around your input terminal for the 10 volts. I'll do my best to look around tomorrow and see if I can get you some more definitive information tomorrow.

Thanks Ed -

I can send you a link to show you exactly how I have the 66 block strapped, if that will help ya any.

Sure, send it on. I'll be happy to take a look for you.

Thanks Ed -

I PM'd you, as I wasn't sure if posting a page from a manual is against forum etiquette.

Thanks!
Matt

Matt:

I've done a little more research. On the intercom card itself, check the jumpers on TC1 and TC2. These are near the edge connector. These should both be in the "B to C" positions for buzzers. TC1 affects the even-numbered stations and TC2 affects the odd-numbered ones. Both should be set the same way.

For 10 volt buzzers, run a single jumper from row 1, terminal 5 to row 35, terminal 6.

For 18 volt buzzers, run a single jumper from row 28, terminal 6 to row 35, terminal 6.

Note that row 35, terminal 6 is the buzzer voltage input to the intercom card. Do not install both jumpers.

Lastly, your card may utilize two-digit dialing, meaning that the dial codes are 10-19 instead of single-digits.

Ed -

Yep, both are in B-C. I've also tried Jumper W in and out, no difference.

I'm currently using the 18v strapping; I've also tried the 10v to no avail. I've never hooked them both up, I imagine that would cause the magic smoke to get out.

I've also tried the 2 digit dialing - i.e. 14 for station 4. When doing this, it presents 18v at station 4 for 1-2 secs, just as only pressing "4" does. The manual says somewhere this capability is there to support up to 20 stations.

I think the main problem right now is I seem to have the voltage required, just not the current (at least at the signal output - if I hook the buzzer to the 18v term on the 66 block, it buzzes, so I've ruled out the power supply as a problem).

For a laugh I even tried one of the 10v line bulbs instead of the buzzer; it won't even drive that.

Oh well, if nothing else I'm learning a heck of a lot about 1A2.

It surely seems as if the other lead from your buzzers isn't reaching a ground connection.

Jumper W is removed if the touch tone adapter card is used and should be removed completely. Jumpers X,Y and Z are for call announce intercom via speakers built-in to the phones. All three of these jumpers are likely not the problem.

The only other straps that I can think of that might help are as follows:

AG: Strap row 27, terminal 2 to row 27, terminal 6. This will place a ground on rows 46 and 48 for lamp and signal grounds used by the intercom.

RG: Strap row 32, terminal 6 to row 34, terminal 6. This ties the ring generator's ground to the other grounds in the system.

One last effort might be to try substituting 10 volts AC for the 105 volts AC input to the intercom card. To do this, connect a strap from row 1, terminal 5 to row 34, terminal 6. Remove any other straps associated with these terminals. Then, on the intercom card, move the jumpers on TC1 and TC2 to positions A and B instead of B and C.

Ed -

I had a jumper from row 27, terminal 2 to row 27, terminal 6, so I was covered there.

I added one from row 32 T6 to row 34, T6.

Still no buzz.

Last night I read that AG needs to also be tied to the incoming ground connection, so I also have a jumper from AG to earth.

Going to try the last suggestion now.

Bingo! No earth ground 1A2 does all kinds of funny things. Ground the grounding lug to earth, water pipe (if not plastic).

Well, no joy in mudville.

The only difference is that I now read 10v across sig term 4 and ground vs. the 18 that was there.



Looks like it's going to be Sam to the rescue...! Although I am on your side of the fence with this card... my gut keeps telling me that something is missing that is unrelated to the card; but I've practically memorized the manual; combining this with all the suggestions you and others have made makes me think there can't possibly be any more configuring to do. The card doesn't have any obvious signs of damage (i.e. burnt resitors or leaking capacitors); and as I've said, it does click when pressing the keyset buttons (in my mind if a relay is clicking, the card is good; I would think all the IC's and associated circuitry are for decoding the signal from the keyset, and the relays do the work of passing the voltage on to the option punchdowns).

I bought the KSU on ebay about 2 years ago, it came with 5 line cards and this intercom card. I pulled the intercom card and it's been sitting on a shelf until this past week; so I have no way of knowing it's particular history. It's just that they seemed to build these things so rock solid that I'm hesitant to blame a card.

I guess my next step could be to pull the back off the KSU, and examine the backplane wiring. That's going to be a lot of work though.... I have the thing mounted pretty securely and I'm also not real keen on the idea of pulling my keysets off (I wire directly to the unit).

Or maybe some of the contacts in the option slot aren't making good contact with the board. One thing I havn't done is to clean them with an alhohol pad; maybe I'll try that.