atcomsystems.ca/forum Forums TDM Business Telephone Systems Panasonic Telephones & Systems High Pitch Noise ??

Greetings, I'm at my wits end on a job. I am getting an intermittent high pitch noise on a dual-cabinet KX-TD1232 w/ a TVS100. It sounds like a wireless access point or something of the sort. I've been chasing this problem for weeks and am running out of ideas. I've eliminated the obvious; UPS,feeder cables, equipment adjacent KSU. According to the customer there has not been any changes since the noise has started. Was wondering if possibly the equipment was at fault. We do not have any spare systems to try. Thought maybe someone else had similar experience that would be of some help. I'm willing to try just about anything at this point. I've got rf filters on all ground wires. Anyway, Thanks in advance!!

were is the noise coming from the ksu's,phones or is it coming from the 100 theres a hard drive in there y'know?

That is the problem; I do not know. Although I powered down the TVS100 and the noise still came and went. I have been unable to find it with my toner probe; so I can't tell where it is coming from.

You can hear the noise on C.O. calls, icm, and voicemail via handset or spkr.

A)go there after hours pop the main breaker in the place bring a generator with a ups or even a just a fully charged ups and and power up the system and see if the noise goes away if it does
you have inside noise issues if it doesn't
you have one or 2 bum cabinets (shame on you
all certified dealers must have a back up ksu)

just remember that after testing with a battery backup as your power source, if the noise is still there then it points to the hardware.

the next thing i would do would be to test 1 cabinet at a time (still using the battery)seperate the two cabinets and strip 1 of them down to the "lowest working configuration" - which means disconnect all CO lines, disconnect all exp cards, and remove all amph connectors. hook up a different amph tail to stations 1-8 and connect only one "known working" phone. pick up on the intercom and if the noise is still there then it's a bum system. if the noise is not there, then start bulding up the system till you find what is causing the noise.

Thanks alot for input fellas. I'll give these suggestions a shot. KX-TD1232's are not that easy to find now days;i.e..no backup KSU.

I have one here staring at me on my desk
and if you want a link I can pm a link too
you the guy is sitting on loads of the stuff
your second plan of attack should be if you
strip all the wiring and c.o.'s and start
ksu by ksu and you find it is the equipment that is making the noise sell them a new 200 to replace the dually if they'll Spring for it

Hello All, thought I'd post latest. I started from scratch;i.e.. one cabinet,one amphenol(eight stations) and it wasn't until the last extention module(there are two) that the noise reappeared. Next step; add one station at a time and see what happens. Sometimes I need knowledge reaffirmed; if that makes any sense. Although I still am curious if anyone else has had ksu be the culprit in regard to phantom noise. Thanks again for input!!!!!

so lets get this right you put the last 170 on
with no amp connected and the noise came back
? if yes then get another 170 on order if the
noise came back only after you reconnected the
amp its in the wiring....have had ports and
cards go bad but when a ksu goes it normally goes all the way.

bluzman, after reading your last post, i'm a bit confused. what did you find to be causing the noise problem, one of the stations or the card?

One last tip... if you think it's the card, before you order another 170 card move and program the card to another expansion slot, in-order to prove it's the card and not the expansion slot on the ksu.

bud have you actually seen a slot go before?

iv'e had where a station exp card didn't work in the middle slot on a 1232 but when we put a CO card there it did work. the problem wasn't programming, the slot only worked for the CO card. we swapped positions and reprogrammed the slots and had no problem.

very interesting those kind of little bugs in the hardware can make you crazy.

Just thought I'd post an update. I've isolated the noise to one of the 170's. I still haven't figured out exactly where the noise is originating. Every time I think I've got it it moves. I've heard the noise on several different pair. I've even pulled the bridge clips and tried finding the noise on equip. side of block. Due to intermittency of noise it's proving to be quite a challenge.

Again; Thanks for input.

Here's my two cents- It sounds like`a bad chip. When they start to fail, they malfunction when they heat up. When it's cool, it works. If you're a musician like me, then you know what "feeding back" is- squealing, high-pitched noise. It sounds like it's a main board problem and ksu needs to be replaced.

Hi All, Here's my latest. I swapped out the 170 that appeared to be the culprit. Reasoning; when I unplugged that module noise went away. Wrong, made absolutly no difference. So, I strip 66 block associated with that 170, and station by station,I reconnect and listen. Got down to the last three stations and noise came back. So my reasoning is it's one of the three. Through process of elimination, I get it down to one station. No noise for a couple of days; then BAM, it's back. The volume of calls seems to have a direct effect on volume of the noise. The crazy part of this thing is the noise is moving around to different stations at diffetent times. Again; thanks for your suggestions.

Bluz, It sounds as the system is notcausing the noise but amplifing an induced noise.
Did you install the station cabling?
It's possible that some of it may be ran parallel
or strapped to some AC conduits or maybe laying on top of florescent lights.
also have you isolated the power to the unit with a good UPS?
Is it possible to go without those stations for a few days?
It's still possible that as JJimm had mentioned that a chip or some other IC is heating up and with those 3 disconnected the load isn't great enough to heat it up.
You may want to swap those 3 stations to another card. If it's 1 or all of those 3 then it should follow. If it's in the IC then it will stay at that card regardless of the field wiring as long as it has the same load on it.
Just a though.
--------------------
MrG

Yes; I did try another filtered UPS. We did not install this KSU; someone else did. And it's been working well since 97'. This noise started back in Nov. and there has been no changes in wiring in the recent past to explain the inductance theory. We are a small outfit and are phasing out Panasonic equipment; i.e..no back-up cabinets. I've has several experiences in the past where the keyset was actually making a similar noise and resetting the tel. cleared the noise. This noise is moving around?? The women that work in this customers office swear it's the building ghosts. I'm beginning to believe them.

bluzman.....do they have MOH? BGM?

Turn off the BGM and see if the noise goes away.

***UPDATE***I narrowed down noise to 1 extension. Pulled it off of block. No noise for several days. Now every once in awhile they hear it very briefly. I'm counting on the receptionist to monitor frequency/volume,etc...
We still are not sure if it increases in porportion to number of calls. It seems to be worse in the morning when they are busiest/on the tele. the most???Thank you all. I disconnected the MOH at the beginning of this adventure; to answer last post.

Greetings All, Got a call from this customer yesterday. I thought we had the problem solved. Now Receptionist is telling me that noise is coming back only when 3 or more CO lines are in use. jjimm's theory is making more sense all the time; due to the noise/call voluume relationship. I suppose I'll switch the cabinet and see what happens. Thanks again!!

Would it not be more cost-effective to just switch out the board, instead of the whole cabinet?

Probably not Bluz, what version is that?
There are quite a lot of TD1232s around.
You may want to check with Sundance 1st as they do provide this board.
The equipment link is at the top of the page, either call or email them.
If he doesn't have any I can PM you a few used equipment dealers that I'm sure would have them.
Just an FYI for all,
Equipment and manual links should always be done through PM or email.
MrG

We chased similar trouble at a local Harley Davidson shop and finally caught the culprit when I noticed a shop tech leaving for the day. Just before he walked out the door, the problem stopped. We had him go back into the shop and turn on everything that he had just shut off. Turns out that they had hooked up a new neon girly sign on the backside of the wall that the KSU was hanging on. The only access to the shop was outside this showroom and through a locked gate, so it just didn't jump out at us immediatly. Look at what is on the other side of the wall, just to be sure there isn't a microwave or Pamela Anderson all lit up.

Hi All, Friday I swapped the cabinets; made what was slave the master and vice verse. Moved the 170's to new master. Now I'll wait and see. A co-worker suggested I try this; assuming the cabinet handeling bulk of traffic will now be secondary cabinet. Make any sense?

Just thought I'd post latest. Since I swapped cabinets there has been no reoccurance of noise. It's been two full working days and no noise. ?? I'm not sure I get it, but we'll see.

:toast: I'm closin the file on this one. For whatever reason; switching the cabinets fixed the problem. Thanks folks for all the assistance!!

BIGGEST mistake you ever made! It WILL come back to git ya! Should have just 'snuck out the back, Jack', QUIETLY. John C. (Not Garand)

Only time will tell. When I get bit, I'll be sure to post. Via Con Dios!