atcomsystems.ca/forum Forums TDM Business Telephone Systems Panasonic Telephones & Systems KX TA824 - tone, but no dial tone

Problem with 6 month old TA824 system. Any handset pickup will give constant tone (not dial tone). No function keys operate, the LCD display is blank, and key pad does not give unique tone when depressed. This has occurred twice . The first time, a system reset restored the system to proper operating status. This time, system reset does not affect system. The system is currently "locked up" in constant tone mode. Any ideas on solution? Thanks

Sounds like you have a processor problem. Unplug all phones from the KSU at the KSU. Plug one display phone into jack 1 with a line cord and perform a RAM clear. This will rule out a wiring issue. Post your results.

Per your instructions - unplugged all phones at KSU, plugged in one display phone into Jack 1 with line cord, performed RAM clear.
RESULT - Phone plugged into Jack 1 worked perfectly. Dial tone heard, function keys and keypad worked. Next, Plugged all phones back into Jacks 1-8. System did not perform properly - back to original problem.

Ok.. you have a short in one of your cable runs. Plug in one extension at a time until you can find the bad extension. Could be the jack, phone, linecord, wiring between KSU or the jack. I usually find problems at the KSU with the plug that plugs the extension into the KSU. You are on the right path to resolution..

Found a short with this process - Sequentially plugged each extension into Jack 1, then went to phone location and checked operation. Suring the process, I found one phone that did not work properly (would not switch between line 1 and line 2, slow to illuminate lights, and other strange actions. Replaced this phone with another, and the new phone worked fine. That convinced me the phone was likely causing the short.
However, I then ran into a little complication. After checking all extensions and replaceing the bad phone, I plugged all the extension lines back into their assigned Jacks at the KSU. Bingo, the same problem as originally encountered - blank LCDs, no dial tones, non-functioning keypads. Just as a double check, I then unplugged the extension of the problem phone(although it had been replaced) at the KSU, and ran a RAM clear. Problem persisted.
My conclusion is I must have another short in the system, even though I only found one short with the initial tests. Any thoughts?

Yes, you probably do have a second problem that the bad set covered up....keep looking one cable at a time....sometimes it needs a set on the end for the problem to show up.

Hang in there... :scratch:

Plug in one at at time to isolate the short. Your problem isn't in the system, It is in the wiring. Isolate the short then repair. You must plug in one extension at a time, test, plug in another extension,test, Voila, your problem extension will appear. You can try replacing all of the clear plugs that plug into your KSU, I don't know your knowledge on telephone systems but I would bet that your problem is in one of the clear RJ11 crimp plugs. Especially if they are crimped on solid cross connect wire.
Where in VA are you?? I was born and raised in VA!! You are getting close..

Update - Back to square one, started over with troubleshooting. Here's the conclusion so far: Any phone plugged directly into Jack #1 at the KSU works properly. With the assigned extension plugged into Jack #1, any other extension line plugged into any other Jack position (i.e., #2-#8) causes system failure - that is, extension assigned to Jack #1 and the other extension plugged into its assigned Jack have blank LCD, non-function keypad, no dial tone. What next?

So if you plug in any extension, it dumps the system??

Any extension plugged in (except extension assigned to Jack#1) will dump the system.