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

Well not knowing if the system is the same as a Bell Key system I'm limited in what I can advise. Doesn't sound to me like you have and voltage going into the card to supply voltage to the buzzers. I've never used that card so couldn't tell you where the input would be. I'll bet Ed knows.

Matt:

Yes, there is an input option for the buzzer voltage, but I can't remember for the life of me if it's a jumper on the card or if it's a physical wire strap. If I were you, I'd clip onto digit 0 with one end of a continuity tester and touch the other lead to the various other clips in the general area of the intercom wiring (one at a time). The numbered clips down the lower right side of the block present the various system voltages and I am pretty sure one of them is your buzzer input. Keep dialing 0 over and over again and watch your continuity tester, each time moving to another clip. When it lights during the buzz cycle, then you found the input. Then, stay in that same area of the block and seek out the 10 volt AC power (note that you can always use the intercom's "L" terminal for your power). Strap a jumper between the two clips and you should be good to go.

Ed -

Thanks much, I'll do just that. Also, another contact pointed me to the holy grail for the KSU:

Edit by Bill: I know this is an old system, but board policy is to not post links to manual sites. Thanks

So now I also have the installation/service manual for the KSU, something I've been wanting for a long time.


PS:

Looks like it's a good thing I didn't mess with the jumper(s) on the intercom card. It switches the buzzer outputs from 10 to 105 volts.
Thanks again, will post back soon with results.

Ooops sorry aabout that.... didn't know.

thanks for the info about those lights

Well, I'm about to call this experiment a failure... perhaps the card is bad. Ed - reading through your last post, it sounds basically like the card needs to be fed the power it will pass on to the buzzers. This appears to be selectable from either 10v or 18v.

The manual says to run a jumper from row 28, terminal 6 to row 35, terminal 6 for 18v. Or to run a jumper from row 1, terminal 5 to row 35, terminal 6 for 10v.

Then another jumper from row 27, terminal 6, to any AG terminal.

I did this (which I think accomplishes what you conveyed), and still no volts at any of the signal outputs when pressing any of the keypad buttons.

I do measure 18v at R28 - T6, and 10v at R1 - T5, using LG for a ground, so I know the power is going in.

I'm going to go study the manual again, perhaps there is a jumper I have set improperly.

Matt -

Good luck with the system. I don't know how much luck you'll have finding a replacement for the Intercom card - it was a fairly late arrival. I'm pretty sure I have some Teltone or Melco Intercoms buried in the basement. In fact I'm pretty sure I have a C-10 or C-19 there (Combination Tone & Rotary). These were stand alone units about the size of a paperback that were designed to work with 1A2 systems. If you're interested, PM me. Assuming one of them still works (which I'm sure they do - they were built to withstand Armageddon) you can have it for the cost of shipping.

Always glad to help out an enthusiast.


Sam

Sam -

Cool - that's a very kind offer; I think I'll take you up on it. Actually I think I saw one of the units you mentioned on Ebay the other day, and am in conversations the seller of it as well, looking for more troubleshooting info on this issue.

Again - thanks - do you have a paypal account? If so, I'll transfer the $ as soon as you can get me the amount due.

Thanks -
Matt

Thanks
Matt

Matt -

Send me an address. I'll dig up the unit and ship it out.

Sam

OK,

Last post about this until I get the intercom unit from Sam (Thanks, Sam!).

I found another manual for my KSU, which had some slightly more specific strapping options. I followed them, and now here is what happens:

I hooked a voltmeter between R48/T5 and each signal output. I didn't see anything on 1, 2 or 3, but when I got to 4, the meter shows approx 18.5 volts when 4 is pushed. Also when 3 is pushed. Thinking maybe I had a keyset that was "out of tune" I hooked up a rotary. Same thing happened when dialing 3 or 4.

But no matter, I thought... I don't really mind if 2 buttons will signal 1 station; at this point I have only 2 keysets installed.

But, of course, I don't get off that easy. When I hook a buzzer to the terminals, I get nothing; almost as if there isn't enough currrent to drive the buzzer. Leaving the voltmeter in parallel with the buzzer shows zero when 4 is pressed.

Hooking the buzzer directly between LG and R28/T6 gets a very definite buzz, so there's nothing wrong with them. I have some buzzers with red leads, some with blue. Both colors seem to work OK at 18v.

So now I'm almost positive it's got to be a bad card. Thought I'd throw this out there for any possible comments though.

Thanks everyone, your help/comments are much appreciated!

- Matt