A question for Panasonic PBX owners

[GG]

Bingster, thanks for pointing that out to me. about the "most recent" link.   D'oh!, I should have looked more carefully to begin with.

[Nick in Manitou]

I know that this thread has been dormant for a while, but it seems like the place to ask a question about the Panasonic 616 (KX-T61610) that I just picked up used from ebay.

(I should state that I don't know anything at all about the Panasonic 616 and not much about the technical end of the telephone in general.)

I have VOIP and purchased the 616 to allow us to connect some of the old phones so that we can hear them ring and dial out using the rotary dials.

Until tonight while I was trying to make the 616 system work, I never tried to get one of the older phones to ring with the VOIP system...BUT as a result of futzing with the 616, I found that at least a couple of the old phones have ringers that will function with the VOIP system.

I have connected the 616 to an incoming VOIP line, connected an older phone to one of the extension ports (11 - 26 ) and although I can dial out with the rotary dial, the phone will not ring when a call comes in.  (This is one that rang on the VOIP system.)

The unit currently has no battery, so the old program should not be an issue.  My impression is that a battery only serves to preserve any programming that is done, so the unit should function in its basic fashion without a battery present.

All I have done is plug the unit into the AC, ensure that the programming switch is in the "Set" position rather than the "Program" position and plugged in the CO line and tried several phones, one at a time in various extension ports.

As I mentioned, the phone that convinced me that I should post this question actually rang very well on the VOIP side, but didn't ring at all when connected as an extension to the 616.  I DID hear clicking in the 616 when the phone should have been ringing. (This might be a clue as to what is going on!)

I probably should mention that I am using a splitter (or whatever one might call a device that has one male end and two female ports) to hang the 616 off the VOIP modem while not interrupting the phone service to the house.

The ad for the unit I purchased said that the unit had been tested.  I obviously don't know what that entailed, but supposedly, it worked for them.

Any suggestions?

Thanks,
Nick

[Phonesrfun]

An incoming call on any of the ports should ring at any and all extensions with the default program.  Where the phone connects to an extension port on the 616, there should ONLY be the inside pair (red and green wires) connected, not pair 2 which is normally connected to the yellow and black wires in a modular cord.  Pair 2 is reserved for power and multiplexed data functions if a proprietary Panasonic extension phone is connected instead of a POTS phone.  Having anything connected to pair 2 on any of the extensions can interfere with the 616's operation.  I would start there. 

[poplar1]

If you call from one extension (11 for example)  to another extension (16 for example), does the called extension ring?

[Nick in Manitou]

Thank you for the suggestion.

I have verified that I have a 2 conductor modular cable connected from the extension port to the phone and that the problem persists.  (Phone not ringing, clicking from the 616.)

Any other suggestions?

Nick
P.S. Poplar1, I just saw your question.  I will give that a try now.

[Nick in Manitou]

Poplar1,

I have just tried calling one extension from another and then reversed that.  In both cases the phones did not ring, but a connection was made between the two extensions when the phones were picked up.  Again, there was a rhythmic clicking from the 616, in the pattern I would expect from ringing.

[Phonesrfun]

You mentioned the clicking sound.  I don't recall mine ever making this sound.  Perhaps it is not as "tested" as it was made out to be.  I will see if mine clicks when dialing an extension.

[twocvbloke]

You mentioned the clicking sound.  I don't recall mine ever making this sound.

My 616 clicks on all calls, internal and external, it's the relays inside operating to connect the ringing current to the extensions in an appropriate cadence to suit the type of call being made...

[Doug Rose]

Nick.... if the extensions do not ring there is a programming issue. Unplug the battery and then unplug the 616 from the AC. It will return to default programming where all exts ring. I run mine on default as it is for my test bench and my phone room. Mine also clicks when dialing. ....Doug

[unbeldi]

The fact that none of your phones ring when connected to the ESS, without a battery, probably indicates that the ringing supply is defective. I would contact the seller, from what I remember about your previous posting, they had multiple units for sale and provided a guarantee.
Do you have any modern telephones such as a cordless phone to try?  Some modern, especially cordless phones, draw very little current when ringing, their REN value is close to zero, 0.1 or smaller.  This might test whether the ESS delivers any ringing voltage.
The unit should click as described, each line has a ringing relay. This at least indicates that the extensions are being addressed at all.
Depending on your energy to explore, rather than get your money back, it might be worthwhile to open the unit and make sure the ringing transformer is connected. Could someone have disconnected it intentionally?  But it should best be the seller's job to figure this out at this juncture actually, until they refund your money.

Before the ringing transformer is a ringing signal amplifier, quite simple and easily debugged and repaired as the power supply circuit board is not densely populated. Its input is a 20 Hz sine wave 10V peak-to-peak synthesized in the CPU. It would be fairly easy to repair if this signal is present, but shipping these unit around the country is too expensive.

[Nick in Manitou]

Thanks for all the responses. 

Last night after I turned off the computer to head to bed, I thought of another thing to try with the system.  I connected a more modern telephone that has an electronic ringer rather than the old mechanical ringers that were in the phones I had tried up to that point.  The electronic ringer functioned when connected to the 616.

Unbeldi is probably on the correct track.

I have sent a message to the seller and have not heard back yet.  While awaiting a response from the seller, I will try to figure out what the "ringing transformer" looks like and if it is connected.  If someone has any documentation or can point me to a photo of where the component is or what it looks like, I would appreciate it.

Thanks for the assistance!

[unbeldi]

ok, that's exactly what I was after.
This means the ringing transformer is indeed connected... no real reason to check that.  But I will attach a picture to this post, it will take me only a few minutes to locate it, I have these units somewhat well documented.

So...  this also means that the CPU generates the requisite sine wave, a big positive.

I suspect that the ringing signal amplifier has a defective stage transistor.  The amplifier is of bipolar design, meaning separate amplifiers are used to amplify the positive and the negative period of the sine wave separately, after which the two are recombined into the ringing transformer.

We now know that at least one of these two parts of the amplifier is working, since your electronic ringer is responding.
Likely the unit has a failure in either the positive or the negative side of the amplifier, and this causes:
a) a ringing signal that has only 1/2 the required amplitude
b) effectively only 1/2 of the design frequency, and thereby missing the resonant frequency of any electromagnetic ringer by half. The electronic ringers don't care much about frequency, but about some voltage level, probably ~45 V AC, which could possibly be achieved with only half of the amp working, because full amplitude is ~90V.


PS:  I added a picture indicating the ringing generator section.

[Nick in Manitou]

Unbeldi,

Thanks for that. 

The unit I have is a version 3 as well, it that is designated by the number '3' in a circle on the ID tag. (?)

I have heard back from the seller and they seem to be responsive.  Their test was to ensure that there was a dial tone on all the ports.

I will forward extracts of what has been discussed here if no one objects.

What would be the best way for a non-engineer/technician to proceed?

I have taken some photos of the lower portion of the unit, showing the area in my unit that you showed in your photo.  I see that the capacitors (?) (the black cans) on the lower (horizontal) PC board all seem to have leaked. One can see in photo -3911 that they seem to have leaked from right to left. (The two cans on the left have also leaked although it can not be see in this photo.)  There is also a rectangular mark on the lower right corner of the upper PC board that seems to line up with the rubber spacer on the back of the front panel.  This may just be due to age, but I figured I'd point it out in case it means anything to anyone.

Photo -3913 is a closeup of the board showing what looks to me to be the material that leaked from one of the cans.

If the cans have leaked, could the unit still function as it seems to be doing?  Is it possible that the problem with the ringing could be fixed by replacing the transistors and the unit continue in service without concern about what seems to be components leaking?

Is replacing the transistors a job for an amateur like me? 

Should I just ask for another unit, or perhaps have the seller send me another board to swap out?  (Would swapping out the board be a matter of unplugging and unscrewing one and replacing it with another?)

[unbeldi]

Yes,  (3) on the ID tag is the version number.

That looks strange. It looks like the unit was mounted sideways.  I am wondering whether that gunk is not actually leaked from the caps, but whether it is a glue used to secure the large caps so that they would not just be supported by their electrical leads.

If it is leakage from the large capacitors, it should be cleaned off, because electrolytes would short out other components.
It's just odd that three of them have leaked identically.

Seeing this, it could also be that the power supply is not providing the necessary power to the ringing amplifier, perhaps there is some kind short from the "leakage".    The ringing amplifier needs two supplies, +16V and -16V, these are not regulated or stabilized, but would be affected by capacitor failure.

It seems there multiple potential sources of problems here. The very large capacitor on the right is also "leaking", it's for the talk battery supply.

Given that it's really not your responsibility to fix the unit, and you don't have the test equipment and experience to test further, I would leave the responsibility with the seller.  He can decide what he wants to do, but you have a right to be satisfied.   You shouldn't have to swap boards either, which is possible, but in the end ... it is tedious.

PS: The transistors in the two parts of the amplifier are complementary (matched) pairs, and are probably impossible or very hard to get anymore,  so if one of them is bad, they need to be replaced in pairs with similar types. I do have the data sheets, but haven't looked for equivalent types.  But now, the power supplies needs to be verified first.

[Nick in Manitou]

I have sent another communication to the seller outlining your take on this, Unbeldi.  I will let you know what the response is.

Thanks