What PBX systems would work for me?

[HarrySmith]

Did you leave it turned off after removing the battery long enough for the capicitors to discharge?

[TelePlay]

What do you have plugged into CO1?

Take that line out of CO1 and see if that does anything.

[Kmoody]

I had it unplugged for several hours without the battery attached.
In the CO1 jack. I plugged in the line from the OOMA voip box.
If I unplug the CO1 line, I still don't have dial tone on the 616.
I think I will open the 616 up again ( I had checked the fuses before) and clean the plugs from the power supply and interface cables between the boards. Maybe, I'll get lucky.

[TelePlay]

What happens if you disconnect all of the phones and plug one phone with an original modular connector into one internal port, #11, then #12 etc. to check for dial tone on each of the 16 lines?

[poplar1]

It works great as an intercom, but no dial tone from the 616.

Do you mean that you can call from one extension to another, the called phone rings, and both parties can hear each other? You just don't hear dial tone?

[poplar1]

Also, I do not have my 616 attached to a landline and if I dial 9, I do not get a dial tone. The dial tone after dialing 9 is the CO dial tone, the outside line dial tone.

You can connect a 2-conductor modular cord to CO6 and any EXT. Dialing that extension # will ring all the other extensions.

[Kmoody]

I can call other extension phones (without dial tone), by dialing their extension. The other phone rings and I can talk between phones.
I have plugged just one  regular original modular corded phone into each jack, no DT on any port.
Is turning off the 616's DT an option on the original programming. That doesn't reset with the reset button or powering down the unit?
I would think this 616 has had all its programing erased, from sitting around for awhile before I bought it, as the caps and battery discharge over time.

[poplar1]

I believe that you have a bad tone generator -- hardware rather than software or programming problem.

What about busy tone (when dialing your own extension number, or an extension that is off-hook) or ringing tone (when dialing an idle extension)?

[Kmoody]

I do not have a busy signal when dialing my own extension, or an extension that is off hook. When I dial an extension that is on hook, I can hear a relay clicking, but no ringing tone on the phone that I'm using, The other phone does ring.
Sounds like the tone generator is bad as Poplar1 mentioned.
I'll have to try to return it on Ebay.

[5415551212]

Thats unfortunate its not working, hopefully they can get you a working one.
If you can't return it, you can check the DC power rails with a multi-meter
I think it needs to generate a few outputs and one might be just for that tone generator, I know someone has posted a service manual on here before, its a few voltage rails like  +18,  +13.4, -5, -5.6, -9, -13.4 -24 ..
There are something like 4 fuses you can check also.
Just a reminder be sure your all your RJ11's to old phones are not using the yellow/black pair, old phones sometimes have yellow a ground and that second pair is a digital signal.

[TelePlay]

Many manuals on the forum but keep in mind there were 2 or 3 versions of the 616 and I don't know what the version changes were. Here's a link to "one" service manual:

https://www.classicrotaryphones.com/forum/index.php?topic=13613.msg168900#msg168900

This link is to a main topic that lists all manuals available/posted on the forum:

https://www.classicrotaryphones.com/forum/index.php?topic=16290.0

The TCI site may also have manuals, and a Google search for a 616 service manual will give other sources, some of which were used to compile what's available on the forum.

Can you post a picture of your 616's number plate (on the bottom edge) which has your model/version number.

[5415551212]

Nice link to the schematic, I struggle with the tiled schematics, but if that one is correct the tone generator runs off the -5V rail. (Note the minus)
Looks like pin 12 of Connector 'CN 4' should have -5V, and pin 14 should have clock. 

[Kmoody]

I'll check that CN4 pin 12 connector tomorrow and see if it has minus 5 volts on it.

[TelePlay]

IIRC, the circled "3" indicates you have version 3, the newest and last version they made. Look for a service manual that covers version 3.

Also, the version 3 never had a battery. There is a huge capacitor mounted on a PCB that provides programming backup during power failures. There is a topic on the forum discussing that "battery backup" for version 3 units:

https://www.classicrotaryphones.com/forum/index.php?topic=14945.0

To erase programming, you have to carefully drain the capacitor.

[Kmoody]

I measured what I could on the voltages. On IC602 ( tone generator) pins 1&3 had -5 volts on them. So I am getting the correct voltage to the IC. On the OPAMP IC 603, I'm getting the correct voltage on pin 4 (18  volts).
My 616 has a battery pigtail on it. So it might not actually a version 3, as the case tag says. There are two capacitors on the 2nd board, but no extra battery. I think I have to give up on this. I've done all the testing that I'm capable of.
Thank you everybody for your help.