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

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.