sundance-communications.com/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Hottest 1a2 system in Florida

OK had my first 1a2 problem today. Recieved a call and the phone went dead, no dial tone on first two lines. Smoke detector goes off and fire alarm is splitting my ears. Ran to panel and it shows zone 1, which is the garage and I run there to see smoke pouring out of the Western Electric panel. Pulled the metal cover off and flames were comming out. Turns out mice had made a nest in there and somehow it caught fire and burned out the CO lines as well as damaged some blocks. Even though I had plugged it with putty, mice had found a way in the 2 inch conduit and filled the whole bottom of the panel with grass and string. Not sure how it caught fire, but what a mess. Good thing I left 3 feet extra cable in the floor box because the end was ruined. No fuses blew on the 1a2 panels or power supply, which are located on the wall outside the box. Still can't figure out how CO lines and extensions from the home pbx could cause such a disaster, but there was thunder in the distance. I have a protector properly grounded at the point of entrance.

It's a good thing you were there to put the fire out! Glad nobody was hurt.

It is possible that the mice had chewed the insulation off of the CO jumper wires and when the call came in the ringing voltage arced enough to set the grass and string on fire. Of course it could have been a lightening strike from miles away that came in over the CO line also.

I've seen lots of cable terminals with mouse nest that had practically all the insulation chewed off the wire and never a fire. I'd guess they got into some of the power leads. Even on a wet cable (old lead paper or pulp) the wet spot would be warm to the touch because of the battery, but never hot. There is the lightning possibility too.

Wow, was this an ITT KEY system? they don't blow fuses as easy as the western electric Stuff does.

This is just my experience. It had to be a lamp lead that set it off. It's one of the things that may cause it. A shorted lamp lead will get hot if the fuse does not blow it may cause a fire.

Was it somthing other than W.E.?

In the past
I would go on troubles on a lot of stuff and see the lamp fuses jumped with cross connect wire. Any small cable trouble with the lamp leads should cause the fuse to blow. Grounding of the power supply is important here. We are dealing with an amp or so and real voltage. With robust power supplies.

My dad was a real good old timer, He did a simple trouble on some Key equipement to make me understand that an old key can cause a fire. Yes, the wires started smoking before he did much damage.

He did this to prove a point..... and to me and teach me about electricity.

He took the fuse out and straped it with crosss connect and said whatch what happens.. When the lamp power supply get's shorted. The lamp battery power leads started to glow red.

I'd never seen that. Hope I never do.

14/24 Volts on the lamps. I would always put the lowest fuse rating I had in my bag. Just rule of thumb. Besides if it blew a week later it gave you time to do your search mission and fix it and another service ticket to boot.

Now the other side of the coin, I would wire the lamps for 24v and if there are less than 15 sets and you go back every other week to change a bulb. The other trick, wire all sets with 14 and they complaine they can't see the lamps. That's after you fixed all the original problems. One more service call...... Besides the secretay looked good.

I've seen wire spring relays fried cause someone went to burnish the contacts and didn't block the battery first. When I think of all the 1A2's I saw with 26 gauge wire where the fuse should be, it's a wonder something didn't get burned down. I helped one of the Telco guys who's 10 button set wasn't working, there wasn't a fuse one, all wire. I put in fuses and left him spares, seems they're always messing around and blowing the fuses.

Man, you gotta use the right fuse. If somethings blowin it somethings wrong. I always trouble shoot to find the cause other than replace w/ jumper. Cant take the risk. A good exterminater or better putty can much better protect your KSU.

When I was in the Air Force we called the jumper wire a "no blow". I never used them but I saw other techs use them over the years. You definitely did not want to get caught using them by a supervisor.

I remember the trouble shooting process like it was yesterday...
1. Remove all the jumpers from the equipment block.
2. Replace the fuse.
3. Punch the jumpers back down until the fuse blew again.
4. Trace the jumper to the "bad" cable or phone, or amp, or whatever was causing the problem.
If you were lucky the telephone had it's own intercom number so you could just call it and ask where they were in the building, otherwise you had to walk all over the place checking each phone.

It sure took a lot of time but you felt like you had accomplished something when you fixed it.

This is a system with two 620 panels and a WE 79B2 power supply. The panel that burned up was a WE H303 which contained punchdown blocks only, it served as the entry point for the CO lines and the VOIP adapters located in the home office. No power runs to or from the box. Because the wires burned I don't know if the mice had eaten the insulation but interestingly there were no dead mice found or mouse droppings in the garage. I have already stripped the remaining paint and dipped the metal in acid and repainted, and replaced the bad blocks and charred plywood backing.

As for the cause I think it may be related to the storms and the contractor installing fiber optic cable. My phones started giving trouble and the Bellsouth tech told me that a lady in an SUV had lost control and rammed the concentrator by the side of the road . Since those things use batteries maybe it got connected to power directly or something? Anyway it drove me nuts as I was back to the box trying to figure out what I did wrong in the repair. The "thunder" I heard may have been the accident. Sur enough when I drove by there the concentrator was bashed in, and a bellsouth truck was there with a funny looking tent and boxes nearby. On my KSU power supply it originally had wires, but I was lucky enough to get fuses with the replacement power supply someone was nice enough to send me.

From now on I am opening that panel once a week!