Legend R7 - 012 w/ Ring Gen. Keeps Blowing!

[dostrow]

HELP!!!

We have a customer with a Legend R7 (lots of Analog Phones) that has obviously been for a long time. We got a call that some analog phones were not working. When we went on-site we found a BLOWN 012 w/ Ring Gen. We replaced the board, the phones all came up. 1 1/2 days later the same slot with the new 012 Blew again. We then went out and replaced the expansion cabinet (with new power supply) that it is in and put in a third 012 with Ring Gen. It is now 1 1/2 days later and we just got a call with the same problem and went on-site to find the 4th Board blown.

Has anyone experienced anything like this? If so, what did you do to rectify it?

I would greatly appreciate anyones help on this.

Thanks!

Don

 

[HiDesert]

You might start looking at what is connected to the 0x12.
Sounds like a s/l device is back feeding or overloading the
board. There might be a defective external alert, fax,
modem, vm card...or battery crossed wiring..After you have
replaced the card for the 4th time...go around and see what
s/l device is acting stupid..

 

[dagwoodsystems]

Does it hold a tune when it blows?

On a more serious note, I agree that it sounds like there's something hanging off the board that's causing the problem. The Partner ACS, Merlin II and oldest Legends have a history of blowing ports due to prolonged shorting and whatnot, but the later one's have proven to me to be fairly bullet-proof.

The only other thing that occurs to me is that you may have moved the Ring Generator from 012 board to 012 board. And that the Ring Generator itself could be the problem. Anything like that going on?

 

[HiDesert]

Even if the RG blew...he would still have station dial tone.
Still proceed with the assumption that you have a defective
s/l device or wiring.

 

[dagwoodsystems]

True. However, there is a possibility that the Ringing Generator is indirectly causing the trouble (what we call a cascading failure). Let's wait and see what other details dostrow gives us.

 

[dostrow]

HiDesert, Dagwood;

Thanks for the response.

As to the 'Ring Generator'. We are actually using cards with the Ring Generator built in. So it is a different Ring Gen. each time we replace the card. My tech is telling me that there are a few other cards that have at least one bad port on them. He remembers that someone once told him a bad port on one card could affect another card. Any ideas on that?

Also, he is now telling me that some of the stations have more then one phone 'daisy-chained' to a single port. That doesn't sound right to me although this is not a new install and this has been set up this way for a long time.

We do need to have some of the wiring cleaned up as it is a mess and it is possible that some wires are shorting.

Any other thoughts?

Thanks again for the response.

 

[dagwoodsystems]

I've seen one port on a board affect other ports on the SAME board. I've also seen board failures cause other boards to appear dead (a failed ETR will cause every board to the left of it to be unusable until the ETR is replaced).

I've never definitively seen a port over in Slot #3 proven to be responsible for a failed port in Slot #5.

But let's not get distracted by the details. The fact that there are several dead ports lends a lot of credability to the idea that there's some shoddy wiring in that shop.

 

[HiDesert]

Loading up on the ringer impedence "could" cause the overload...are you getting latest vintage 0x12 cards or
are they the older cards....that might be the difference.
Just a thought.

 

[dostrow]

How about the fact that apparently there are analog ports that have more then one phone hanging off of them (daisy chained)?

Is it possible that that is causing a bigger power draw and somehow frying the boards?

 

[dostrow]

The cards that we are using are 517H13's. The different versions we have are 517G13(28), H13's, and J13's.

Also, apparently now only the last 4 ports are blown, not the whole card. With, at least, one of the other cards we replaced the whole card blew and you could smell the card burning.

 

[HiDesert]

look at the lowest port that is OD....bet you thats the
culprit...check and see whats on that port..and work your way up. Daisy chaining a few sets together shouls not a
problem...the old E1A external ringer used to be one of the
issues...., but your getting close.
We'll get this problem fix yet!!!!!!!!!!!!

 

[dostrow]

HiDesert;

Thanks again!

We will be back out there next week and will work our way through it.

I will keep you posted.

 

[allisland]

Take a close look at the PC board, you'll probably find a burn mark,just to the left of the jacks(jacks facing right)( if your eyes are anything close to mine you'll need a magnafying glass that's the sta port causing it to blow, remove that sta and then replace the board, then when that stays in service, trouble shoot the wiring for that sta. had a few like that that were grounding out to metal studs

 

[phonesrus]

You could make an adapter with a couple of screw terminal biscuit jacks that would let you place a milliamp meter in series with the ring lead and connect between the switch and the station cable at the PBX and test the loop current and the ringing current (separately of course) on each connected set, using a meter with AC and DC Milliamps. You could have a phone with a leaky ringer capacitor that is overloading the RGen. Or,as stated above, cabling issues!
It's tedious, but cheaper than cards in the long run.

PBX tip 0---------------------------0 tip station
ring 0---------0 0--------0 ring
|_meter__|

If you have a Tempo kick meter you could test the loops that way too!

 

[dagwoodsystems]

Are any of those stations extended out of the building? And if so, what is the longest distance of those extended runs? Thanks in advance for your reply.

 

[dagwoodsystems]

Are you still around dostrow? Please post back when you have a moment. I need closure, man.

 

[dostrow]

dagwoodsystems;

Sorry for not getting back to but even thouh some of the ports are blown we haven't gone back out to the site.

As to your question about stations extended out of the building; this is not the case. To my knowledge there are no stations that are extended that far.

We are supposed to go to the site tomorrow. We will be focusing on the wiring and the devices that hare hanging off of the 4 ports that always blow (mostly the top 4 ports have blown, but in at least one occasion the whole card blew).

I will get back to you (all) and let you know what we come up with.

Thanks again.