Hello friends,
I bought a PT for my Panasonic 308 off of ebay: a KX-T7030. When I connect it to ext. 11 (CO line to #1), it is dead as a door nail. I switched out the line cable with a known working one. I know the 308 works when our cordless phone is connected to ext.11. Is there something obvious that I am missing?
Thank you for the input,
Tina Loyd
As far as I remember this phone use 4 cords, the 4 in the middle of th RJ plug.
dsk
Yes, a 4-wire cable is needed, the inner pair is voice, the outer pair is data, without the outer pair, the phone will appear dead...
Thank you!
OK, this is a stupid question but can I tell the difference between a 4-wire cable and the "regular" kind? :-[
Tina
I went and looked at these cords and the one that was shipped with the phone looks to be a four-wire cable. I swapped it out two others and still nothing.
Please keep the suggestions coming!
Tina
With the cord unplugged, count the gold-plated connectors in the plug on either end of the cord. It should have 2, 4, or 6 gold pins.
I am going to point you to this topic about the great array of different Panasonic pbx's and analog/hybrid/digital telephone sets to try to determine that you actually have a compatible phone.
http://www.classicrotaryphones.com/forum/index.php?topic=13519.0
At a quick glance I think the phone you bought looks to be one that would work with the type of Panasonic PBX's that support analog stations as well. But, is that the type of Panasonic PBX you have?
If it is compatible, I am not certain if there is a polarity issue with these phones or not. It is very easy to have a 4 conductor set cord that reverses the polarity of each pair. I know that many digital Nortel sets would appear dead if the polarity were reversed. Simply having a plug crimped on rotated 180 degrees from how it should be will reverse the polarity to the phone.
One more thing. Generally counting the number of brass pins in the plugs is indicitive of the number of cord conductors, it isnt guaranteed. Look to see how many individual conductors there seem to be in the cord. A 4 pin plug can be crimped onto 2 conductor cord and a 2 pin plug could be crimped onto a 4 conductor cord as well. Either of these combinations will only add up to 2 working conductors.
Terry
Quote from: poplar1 on February 02, 2016, 05:20:03 PM
With the cord unplugged, count the gold-plated connectors in the plug on either end of the cord. It should have 2, 4, or 6 gold pins.
The upper section about RJ 11 here could help: http://www.westernet.net/Help/RJ45.htm
It could be 4 or 6 golden pins, and the middle 4 should have wires.
dsk
Tina .... I'm sure you've probably already checked this, but every now and again, we all miss something obvious. According to the set's "Operating Instructions", there is a "handset / headset" selector slide switch on the back of the set. If your using the set's standard handset, that slide switch needs to be set to handset. The handset / headset switch should be the center switch in a group of 3 switches on the back of the set to the left of the line cord.
If it's already set to the proper position, disregard this posting.
Jeff Lamb
Also, try plugging the proprietary phone into some other extension jacks.
"The upper section about RJ 11 here could help: http://www.westernet.net/Help/RJ45.htm
It could be 4 or 6 golden pins, and the middle 4 should have wires.
dsk"
I greatly appreciate all of the input. I will do more problem-solving when I get home and take pictures to post as well.
dsk, I looked at the westernet link and it talked about the black wire being on the left in the cable/RJ-11 (tab on the underside) and stays there to the other end and enters the RJ-11 (tab down). Does that mean that the black wire is on the right side of the opposite RJ-11 plug? Wouldn't that make it directional? I have never noticed that in my casual use of phone cable.
Anyway, I already tried turning the cable end for end to ensure that wasn't the case. Should I try it again to make sure?
Thanks,
Tina
What is the model number of the Panasonic phone.
What is the model of the Panasonic KSU.
Panasonic made many different models of phone's and systems. Not all Panasonic
phones work with all other Panasonic systems.
Quote from: cloyd on February 02, 2016, 01:32:26 PM
Hello friends,
I bought a PT for my Panasonic 308 off of ebay: a KX-T7030. When I connect it to ext. 11 (CO line to #1), it is dead as a door nail. I switched out the line cable with a known working one. I know the 308 works when our cordless phone is connected to ext.11. Is there something obvious that I am missing?
This is my original post
Thanks for the input!
Keep it coming.
Tina
Quote from: cloyd on February 03, 2016, 05:44:47 PM
I bought a PT for my Panasonic 308 off of ebay: a KX-T7030. When I connect it to ext. 11 (CO line to #1), it is dead as a door nail. I switched out the line cable with a known working one. I know the 308 works when our cordless phone is connected to ext.11. Is there something obvious that I am missing?
A 308 has 8 extensions - it you have 11 extensions on a 308 you must have optional boards installed. Not all optional boards support both SLT and proprietary telephones. Some are SLT only and some are proprietary only.
Have you tried plugging the proprietary phone into Ext 1 or 2?
Sorry if this has already been covered.
Jack
Quote from: Jack Ryan on February 03, 2016, 06:08:02 PM
Quote from: cloyd on February 03, 2016, 05:44:47 PM
I bought a PT for my Panasonic 308 off of ebay: a KX-T7030. When I connect it to ext. 11 (CO line to #1), it is dead as a door nail. I switched out the line cable with a known working one. I know the 308 works when our cordless phone is connected to ext.11. Is there something obvious that I am missing?
A 308 has 8 extensions - it you have 11 extensions on a 308 you must have optional boards installed. Not all optional boards support both SLT and proprietary telephones. Some are SLT only and some are proprietary only.
Have you tried plugging the proprietary phone into Ext 1 or 2?
Sorry if this has already been covered.
Jack
The first extension number on a 308 system is No. 11. They don't start at 1. A 308 or 616 system cannot be extended with addons, except for the door intercom module which plugs into the rear bay.
The question that has not been answered so far is whether this PT works on any of the other ports of the PBX. While it cannot be used to configure the PBX features on other ports than the first (Ext. 11), it should still work and the LCD display should show the time. This will at least establish the functioning of the telephone.
If this test is passed, and the phone does not 'light up' on Ext 11, then one has to assume that Ext. 11 is bad. The two outer leads (pins 2 and 5) of the 6P4C connector also provide DC power to the telephone. Each port has a protection circuit that can shut the power to the phone off if it draws too much current.
I have heard about systems that didn't provide power to entire groups of ports, but that was on 616, IIRC, where some support chips in the system are dedicated to eight ports, having two of those components internally.
Here is more information for everyone. I really do appreciate all of the help.
The phone does not have power on any of the extension lines 11-19. I know extension 13 doesn't work with my WE500 but all of the others do work. Doesn't that show that the outer two wires are OK? They are getting power if not data.
I checked all of the cables that I have been switching out and they are 4 wire cables with one being a 6-wire cable.
I have included photos and I am happy to supply more if necessary. Perhaps someone with an eagle eye will spot something wrong.
Thank you,
Tina
These are just photos of the other cables that I have tried replacing the original 4wire cable with.
Quote from: unbeldi on February 03, 2016, 08:03:37 PM
The first extension number on a 308 system is No. 11. They don't start at 1. A 308 or 616 system cannot be extended with addons, except for the door intercom module which plugs into the rear bay.
In that case the US 308 is totally different from the Australian version. The Australian version can be extended and although the extension numbers do not start at 1, the extension jacks do.
Jack
Attached is an installation manual for the Panasonic KX-T30810 is attached. I don't have time at the moment to start reading the relevant portions of the manual, however it does state that ext. 11 "MUST BE" a Panasonic KX-T30830 proprietary telephone set. That's stated on page 1-4.
I'll have a better look at the manual in the morning unless someone else has time to look at it.
Jeff Lamb
Quote from: Ktownphoneco on February 03, 2016, 10:22:33 PM
Attached is an installation manual for the Panasonic KX-T30810 is attached. I don't have time at the moment to start reading the relevant portions of the manual, however it does state that ext. 11 "MUST BE" a Panasonic KX-T30830 proprietary telephone set. That's stated on page 1-4.
I'll have a better look at the manual in the morning unless someone else has time to look at it.
Jeff Lamb
Well, when these system were designed and the manuals were printed, the KX-T30830 was the only PT set that had the feature. The 7030s came out with a later generation of KX-systems, but were designed for backward compatibility. I posted a chart at one time that outlined some of that. The KX-T30830 sets are rather hard to find these days, and usually at a high price, while 7030s are cheap and apparently plentiful.
I do have a 30830, so I have not found the need to actually test the compatibility, but we do have several posts here where this was discussed.
Quote from: Jack Ryan on February 03, 2016, 09:18:34 PM
Quote from: unbeldi on February 03, 2016, 08:03:37 PM
The first extension number on a 308 system is No. 11. They don't start at 1. A 308 or 616 system cannot be extended with addons, except for the door intercom module which plugs into the rear bay.
In that case the US 308 is totally different from the Australian version. The Australian version can be extended and although the extension numbers do not start at 1, the extension jacks do.
Jack
You are probably referencing a system from a different generation. Even the British versions of these are essentially the same and none of these early small types were expandable. The largest of the series, the 123210 used plugin cards for groups of station, and these were available with not all cards installed.
There were some models, however, and I may be thinking of the first generation 616 (not 61610), that had the extension number starting at 21, IIRC.
Quote from: cloyd on February 03, 2016, 08:44:18 PM
Here is more information for everyone. I really do appreciate all of the help.
The phone does not have power on any of the extension lines 11-19. I know extension 13 doesn't work with my WE500 but all of the others do work. Doesn't that show that the outer two wires are OK? They are getting power if not data.
I checked all of the cables that I have been switching out and they are 4 wire cables with one being a 6-wire cable.
I have included photos and I am happy to supply more if necessary. Perhaps someone with an eagle eye will spot something wrong.
Thank you,
Tina
The power supplied on the outer pins is only for operation of the digital circuitry in the phone, including the display, not for operating the transmitter and dial on a traditional analog phone connected to only the center pins. Those carry the normal signals needed for standard analog phones, i.e. talk battery and ringing.
Thanks Karl. That's good to know.
Jeff
Quote from: unbeldi on February 03, 2016, 10:42:50 PM
You are probably referencing a system from a different generation. Even the British versions of these are essentially the same and none of these early small types were expandable. The largest of the series, the 123210 used plugin cards for groups of station, and these were available with not all cards installed.
Perhaps, but different from what? There was no specific model given that I noticed. I was referring to a KX-TA308 which is expandable.
Jack
Quote from: unbeldi on February 03, 2016, 10:42:50 PM
Quote from: Jack Ryan on February 03, 2016, 09:18:34 PM
Quote from: unbeldi on February 03, 2016, 08:03:37 PM
The first extension number on a 308 system is No. 11. They don't start at 1. A 308 or 616 system cannot be extended with addons, except for the door intercom module which plugs into the rear bay.
In that case the US 308 is totally different from the Australian version. The Australian version can be extended and although the extension numbers do not start at 1, the extension jacks do.
Jack
You are probably referencing a system from a different generation. Even the British versions of these are essentially the same and none of these early small types were expandable. The largest of the series, the 123210 used plugin cards for groups of station, and these were available with not all cards installed.
There were some models, however, and I may be thinking of the first generation 616 (not 61610), that had the extension number starting at 21, IIRC.
The British KX-T30810BE has extensions 21-28, not 11-18. The manual below shows a KX-T7130E for programming; so it's not only the early version KSUs that have 21-28.
http://www.htcnetworks.co.uk/308%20Installation%20manual.PDF
(link provided by twocvbloke: http://www.classicrotaryphones.com/forum/index.php?topic=13541.msg141652#msg141652)
Quote from: unbeldi on February 03, 2016, 10:48:30 PM
Quote from: cloyd on February 03, 2016, 08:44:18 PM
Here is more information for everyone. I really do appreciate all of the help.
The phone does not have power on any of the extension lines 11-19. I know extension 13 doesn't work with my WE500 but all of the others do work. Doesn't that show that the outer two wires are OK? They are getting power if not data.
I checked all of the cables that I have been switching out and they are 4 wire cables with one being a 6-wire cable.
I have included photos and I am happy to supply more if necessary. Perhaps someone with an eagle eye will spot something wrong.
Thank you,
Tina
The power supplied on the outer pins is only for operation of the digital circuitry in the phone, including the display, not for operating the transmitter and dial on a traditional analog phone connected to only the center pins. Those carry the normal signals needed for standard analog phones, i.e. talk battery and ringing.
Have we decided that my 308 is faulty? I can still use it to handle my extensions but I would rather they didn't all ring at night. Is there any way to program without the Proprietary Telephone?
Unbeldi, as I recall, you told me that when I turn off the 308, out cordless phone will still operate but the extensions will not. Correct?
Thank you all,
Tina
Tina
We know that the third ext. port is dead. And that your 302 won't function on the system.
However, we still don't know if it's a bad KX-T7030 phone, or a bad KX-T30810 key system.
Quote from: Jack Ryan on February 03, 2016, 11:20:08 PM
Quote from: unbeldi on February 03, 2016, 10:42:50 PM
You are probably referencing a system from a different generation. Even the British versions of these are essentially the same and none of these early small types were expandable. The largest of the series, the 123210 used plugin cards for groups of station, and these were available with not all cards installed.
Perhaps, but different from what? There was no specific model given that I noticed. I was referring to a KX-TA308 which is expandable.
Jack
I see, that is what I suspected. The TA line was called the
Advanced Hybrid System and came out later and was indeed modular. Here on the forum there is a long-standing tradition, so it seems, to call the early models just by their 3-digit number, rather than the full model number, KX-T...
The first series of these was indeed just numbered by three digits, KX-T206, 308, 616, 1232. The next series added two digits (10), KX-T20610, 30810, 61610, 123210.
We should be more precise in naming these, as Panasonic made at least four of five system generations that used the three digit designations as the 'core' identifiers. I think this has caused confusion in the past.
See here (http://www.classicrotaryphones.com/forum/index.php?topic=13519.msg141328#msg141328) for my (also incomplete) summary.
Quote from: poplar1 on February 04, 2016, 01:08:02 AM
Quote from: unbeldi on February 03, 2016, 10:42:50 PM
Quote from: Jack Ryan on February 03, 2016, 09:18:34 PM
Quote from: unbeldi on February 03, 2016, 08:03:37 PM
The first extension number on a 308 system is No. 11. They don't start at 1. A 308 or 616 system cannot be extended with addons, except for the door intercom module which plugs into the rear bay.
In that case the US 308 is totally different from the Australian version. The Australian version can be extended and although the extension numbers do not start at 1, the extension jacks do.
Jack
You are probably referencing a system from a different generation. Even the British versions of these are essentially the same and none of these early small types were expandable. The largest of the series, the 123210 used plugin cards for groups of station, and these were available with not all cards installed.
There were some models, however, and I may be thinking of the first generation 616 (not 61610), that had the extension number starting at 21, IIRC.
The British KX-T30810BE has extensions 21-28, not 11-18. The manual below shows a KX-T7130E for programming; so it's not only the early version KSUs that have 21-28.
http://www.htcnetworks.co.uk/308%20Installation%20manual.PDF
(link provided by twocvbloke: http://www.classicrotaryphones.com/forum/index.php?topic=13541.msg141652#msg141652)
Ok, thanks for clarifying that.
I couldn't remember actually just which one it was that started not at 11. I had one of those some, perhaps ten or so, years ago, and didn't record the details of what it was. These systems were made for many countries with specific details, that I think were simply software nuances.
Quote from: cloyd on February 04, 2016, 09:01:47 AM
Quote from: unbeldi on February 03, 2016, 10:48:30 PM
Quote from: cloyd on February 03, 2016, 08:44:18 PM
Here is more information for everyone. I really do appreciate all of the help.
The phone does not have power on any of the extension lines 11-19. I know extension 13 doesn't work with my WE500 but all of the others do work. Doesn't that show that the outer two wires are OK? They are getting power if not data.
I checked all of the cables that I have been switching out and they are 4 wire cables with one being a 6-wire cable.
I have included photos and I am happy to supply more if necessary. Perhaps someone with an eagle eye will spot something wrong.
Thank you,
Tina
The power supplied on the outer pins is only for operation of the digital circuitry in the phone, including the display, not for operating the transmitter and dial on a traditional analog phone connected to only the center pins. Those carry the normal signals needed for standard analog phones, i.e. talk battery and ringing.
Have we decided that my 308 is faulty? I can still use it to handle my extensions but I would rather they didn't all ring at night. Is there any way to program without the Proprietary Telephone?
Unbeldi, as I recall, you told me that when I turn off the 308, out cordless phone will still operate but the extensions will not. Correct?
Thank you all,
Tina
Tina
Yes. When the system is powered off or looses utility power, the relay switches on each of the first three ports reset and connect the station ports directly to the CO ports, so that the PBX is taken completely out of the telephony paths.
CO line 1 ----> Ext. 11
CO line 2 ----> Ext. 12
CO line 3 ----> Ext. 13
In this power fail mode, the proprietary telephone should still work to make a call, but the phone will not ring on incoming calls, nor will the display function. But when picked up you should have dial tone. A standard analog telephone functions as if directly connected to the CO line, in fact they are directly connected in that case.
That said, you can plug the proprietary telephones directly into a PSTN line, and they can dial calls in either pulse mode or touch-tone mode.
Quote from: poplar1 on February 04, 2016, 09:15:28 AM
We know that the third ext. port is dead. And that your 302 won't function on the system.
However, we still don't know if it's a bad KX-T7030 phone, or a bad KX-T30810 key system.
What else can I do to determine whether it is the 308 (Easa-phone system) or the proprietary telephone (KX-T7030) that is causing problems? If I bring my 7030 phone with me to school and plug it in where my Cisco IP Phone 7911 is plugged in, should it work?
Tina
Quote from: cloyd on February 04, 2016, 06:49:08 PM
Quote from: poplar1 on February 04, 2016, 09:15:28 AM
We know that the third ext. port is dead. And that your 302 won't function on the system.
However, we still don't know if it's a bad KX-T7030 phone, or a bad KX-T30810 key system.
What else can I do to determine whether it is the 308 (Easa-phone system) or the proprietary telephone (KX-T7030) that is causing problems? If I bring my 7030 phone with me to school and plug it in where my Cisco IP Phone 7911 is plugged in, should it work?
Tina
Your Cisco 7911 is a VoIP set that uses Ethernet for communication to a Cisco call manager system. Under no circumstances should you even try and the connectors are not even compatible. Ethernet uses an 8P8C connector.
Have you verified audio operation just by plugging it into an old fashioned telephone line? That's the first baseline test for about 1/2 of the internal circuitry.
To test the rest, a functioning PBX is needed.
Have you verified audio operation just by plugging it into an old fashioned telephone line? That's the first baseline test for about 1/2 of the internal circuitry.
To test the rest, a functioning PBX is needed.
[/quote]
By "old fashioned" do you mean a land line? Is the "audio operation" a dial tone or something more or something else?
Tina
Quote from: cloyd on February 05, 2016, 02:29:41 PM
By "old fashioned" do you mean a land line? Is the "audio operation" a dial tone or something more or something else?
Tina
Yes, a landline would be ok, or any standard telephony service with an RJ11 jack, your cableTV modem telephone jack, or other voip ATA. When plugged into any of these, the 7030 should work fine for placing a call. When picking up the handset you hear dial tone, and you can dial a number and converse with someone. Everything that is needed inside the phone for this purpose is powered from the center two pins, just like for any other telephone. The outer two pins on the connector serve the digital aspects of the set for data and power, to run the display, to run the feature and line buttons, etc. None of these will work when connected to a telephone line.
If that doesn't work, then there is probably little hope that it will work with the Panasonic PBX.
This is probably frustrating to you without electronics experience and test equipment, for which no one can blame you, really. So it requires some tenacity to work through these issues... Old electronics always brings with it the risk of failing or not working, whether it is an old phone or an old PBX. These boxes are long past their expected lifetime, we can agree, despite of being built still before the modern era of throw-away-buy-new electronics, that appears to be designed often to only last long enough until the marketing department decides they need a new model number anyways.
Anyhow, perhaps you might want to look out for a local electronics hobbyist that can help hands-on with these difficulties and troubleshooting.
Was the KX-T7030 advertised on eBay as working properly?
Quote from: unbeldi on February 05, 2016, 02:37:23 PM
Quote from: cloyd on February 05, 2016, 02:29:41 PM
By "old fashioned" do you mean a land line? Is the "audio operation" a dial tone or something more or something else?
Tina
Yes, a landline would be ok, or any standard telephony service with an RJ11 jack, your cableTV modem telephone jack, or other voip ATA. When plugged into any of these, the 7030 should work fine for placing a call. When picking up the handset you hear dial tone, and you can dial a number and converse with someone. Everything that is needed inside the phone for this purpose is powered from the center two pins, just like for any other telephone. The outer two pins on the connector serve the digital aspects of the set for data and power, to run the display, to run the feature and line buttons, etc. None of these will work when connected to a telephone line.
If that doesn't work, then there is probably little hope that it will work with the Panasonic PBX.
When I plug the phone directly into the wall jack, I still get no signs of life. I think I will ask for a refund and get another phone off ebay. Or not. If it will work without going through the hassle again, I may wait awhile. I still have to get the house wired to serve my old phone extensions anyway. IF I get a new P.T., I will know how it should work!
Thank you for all of your help!
Tina
A KXT7030 telephone set will not give dial tone if plugged into a standard POTS wall jack. It needs the power from the outer two wires to make it work. Even though a legacy POTS analog phone will work when plugged into a 308, the reverse is not true. The 7030 needs to be mated with the proprietary PBX to work.
This thread seems to be long and I haven't been following it, and so this might have already been pointed out, but have you tried the KXT7030 in the 308 with no other items plugged in? If any other item plugged into an extension jack has a short or a cross between the outer pair and inner pair, it would probably keep the entire system from functioning. The outer pair of wires is both a power source and a multiplexed signal source for all the functions like the lights and buttons. Maybe that has already been suggested.
If your phone does not work, I think I have one I could sell, but it is black.
I located a service manual for the 7030 with the circuit diagram and I have to agree with you now, after studying it a bit.
The 7030 did not have power-fail feature. It has only one power supply connection to the outer pins.
In comparing the operating manuals with the 30830 set, which was the original 'programming' (configuring, really) PT for the KX-T308(10), it is notable that the power-fail feature is not mentioned in it, as it is for the 30830. Unfortunately, I have not found a service manual for the 30830 so far, and have to go by my pictures of the circuit board of the unit I have.
Interestingly, the 123230, also does not seem to provide it, for which I do have a circuit diagram.
Tina, sorry to have led you on an excursion, but at least we learned an additional bit of info about these.
In looking at the list of telephones compatible with the KX-TA series of PBXes, which Jack mentioned, there is listed a 7033, which does seem to have a power-fail switch, not the automatic fail-over as on my phone.
Also lacking in the 7030, appears to be the capability to use pulse-dialing in the telephone, which makes sense since it doesn't support the analog line feature. Clearly the intend was to produce a line of cheaper telephones in the 7000 series.
Attached is the manual set that I have for the 7030:
- Reference Manual
- Service Manual
- Operating Instructions
Quote from: Phonesrfun on February 05, 2016, 11:11:09 PM
A KXT7030 telephone set will not give dial tone if plugged into a standard POTS wall jack. It needs the power from the outer two wires to make it work. Even though a legacy POTS analog phone will work when plugged into a 308, the reverse is not true. The 7030 needs to be mated with the proprietary PBX to work.
This thread seems to be long and I haven't been following it, and so this might have already been pointed out, but have you tried the KXT7030 in the 308 with no other items plugged in? If any other item plugged into an extension jack has a short or a cross between the outer pair and inner pair, it would probably keep the entire system from functioning. The outer pair of wires is both a power source and a multiplexed signal source for all the functions like the lights and buttons. Maybe that has already been suggested.
If your phone does not work, I think I have one I could sell, but it is black.
Bill,
Thank you for giving me more advice. I unplugged all other items and still no life in the 7030. I then tried to only plug in the CO line and, again, nothing. If you have another 7030 that you could part with, PM me with a price. At least I would know that it worked.
Thank you,
Tina
Quote from: cloyd on February 06, 2016, 01:42:11 PM
Bill,
Thank you for giving me more advice. I unplugged all other items and still no life in the 7030. I then tried to only plug in the CO line and, again, nothing. If you have another 7030 that you could part with, PM me with a price. At least I would know that it worked.
Thank you,
Tina
Tina, Here is a photo. It is in fair shape and it checks out on my 616, and it should work on the 308 from all the documents I have read.
I will PM with a price.
-Bill
Reviewing the entire thread, it does seem to me that the most likely culprit of having a defect is most likely the PBX. After all, the third port is known to be defective already, even for standard SLT telephones. Another aspect I find strange is that a 302 would not work in the system. I have never had a 302 not working on any of my KX-T30810s or 616s, I still have two each. The only problems I recall are some intermittent ring trip issues with a 534A subscriber set connected to a 308. The 534A has a low impedance ringer, as we know.
I would be cautious of buying another PT, just to experiment. The money may be better spent at first by buying a simple handheld multimeter at HomeDepot, which will come in handy in many circumstances a collector may face. It should be easy to measure the voltage on the outer pins of jacks. It should be ca. 12 to 13 Volts DC. Simply use a four-conductor modular cord from one of the jacks to a loose (not installed) modular wall connecting box--also available at HomeDepot, I think, but much cheaper when harvested from old telephone installations or at your local ReStore outlet. Open the box, and measure between the yellow and black terminals.
Tina:
Unbeldi brings up a good point. It is my recollection that inside the 308 and 616 are little glass fuses for the DC power supply. Getting the cover off the main unit is not that difficult; there are several screws, and there may be yet another cover over the power supply (I can't remember), but the power supply is found in the lower part of the cabinet and is obvious by a couple of large transformers and capacitors. MAKE SURE IT IS UNPLUGGED BEFORE YOU START.
You can even visually inspect the fuses for being blown even without a multimeter. However a multimeter will aid in doing a continuity check on the fuses, because those little suckers are hard to see sometimes!
It's going to be a day or so before I can get the phone ready to be sent, since I need to go and get a box, etc and my work schedule is insane, so in the meantime....if you have the time.... you might want to check out that part.
Bill & Karl bring up some good points. My 616 was blowing one of the aforementioned glass fuses, about every 12 months. After the same fuse blew for the second time, and for no apparent reason, I installed a surge protector (SP) on the 120V wall receptacle, and pluged the 616 into the SP. That glass fuse inside the 616 hasn't blown since.
Jeff Lamb
The fuses are rated 250 V / 1.5 A. I don't have a spec whether they are fast- or slow-blow, but I would use slow here.
They are just before each of the two rectifiers.
I don't seem to have a picture of the 308 power supply board, but I have one from a 616. The fuses are clearly seen in the center, both at right angle to each other.
I think I will be able to find and check the fuses. I have a multimeter but never learned how to use it. I understand what you mean by connecting the 308 to an uninstalled jack and testing it. I'll use YouTube to figure out the multimeter. I am glad you guys haven't given up yet! I'll certainly check the fuses tonight.
Tina
Well, no better time to figure out that instrument.
From magnifying the image, you can actually see the wires inside the fuse.
Set your multimeter to a low ohm scale, 2 ohms or 20 ohms, and touch the test probes to the metal caps at each end of the fuses.
The reading should be close to 0.00, zero.
You can also pull those fuses out of the socket and check them visually.
Hello all,
I was able to find the two fuses last night and they looked OK. I could see the wires inside and they are intact and not burned out. I gave the whole board a once-over and could find no broken connections and no goo, bulges or blackened areas. (I apologize for the technical lingo there.) I would still like to try the multimeter; I have been working late and tend to crash early in the evenings. Not a great time of day to be dinkin' around with electrical equipment or anything that requires a modicum of brain power.
Tina
Good work.... But visual inspection is really only good if it yields a result of "blown fuse".
The meter should be definitive.
Well! I'm feeling pretty chuffed!
I was having a hard time figuring out my cheap multimeter and then realized that the furnace guy had left his Fluke deluxe meter! I feel pretty confident that I did it right. We'll see what you all think.
I tested the outer pins on the cable that came with the phone and got continuity on each pin.
With the 308 unplugged, I tested the fuses and got .3 ohms on each. Is that near enough to zero?
To be clear, to test the extensions, I plugged in a cable with a modular cord into one extension (at a time) and then plugged the other modular end into a disconnected wall jack. Then, with the 308 plugged in and turned on, I measured the amps by putting the leads to the black and yellow connections in the wall jack.
The extension results:
ext.#/AmpsVolts
11 = 12.2
12 = 12.2
13 = 5.13
14 = 5.3
15 = 5.3
16 = 15.0
17 = 15.0
18 = 15.0
Do these numbers make sense? Remember, extension 13 wasn't working with my standard phones. (Unbeldi, I rewired my 302 to match another one that I have and now it works. Sorry for the confusion.)
I sure hope this narrows things down. Let me know what this tells us.
Tina
Excellent! Having a Fluke meter is deluxe, indeed. One of the best brands.
Yes, 0.3 ohms is very good. You have to figure into the equation the resistance of the probe wires, and those come out usually as a few tenths of an ohm.
Your table is great, and shows that you do have some problems (PS: no, your PBX I should have said). You column should be labeled "Volts" not Amps, though.
12 to 13 volts is perfect, I am surprised how ports 16-18 can have such a high voltage, but it's not outrageous. But ports 13-15 are way off, too low to run a PT, I think. But I haven't tried running mine so low.
Something is wrong with your PBX.
PS: I don't see a reason off-hand why the voltages would vary so much... I have measured a 308... so I have to consult my circuit diagrams and think about it.
Did you by any chance also measure the talk battery voltage on the two center pins of the ports?
PS: In the meantime I looked at some circuit diagrams. It is puzzling that 3 ports would show 15V instead of 12. It's easier to loose voltage, but to gain it is different. If your measurements are correct, I think there must be something shorting the supply to the 18 V supply.
The system has essentially two power supply circuits, those two are protected with the those two fuses. The two supplies generate a total of four voltages: 5 V, 12 V, 18 V, and 26 V.
26 volts is for the analog talk battery of the station ports. It is also the DC that is superimposed while ringing. It makes it easier and quicker to detect the off-hook transition of the attached phone during the ringing cycle. The 26 volt supply also generates 18 V which seems used for relays and other switching circuits.
12 V runs the PT sets on each station port. The 12 volt supply also generates 5 V to run the CMOS logic, CPU etc.