atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems In SV8300,single line voltage is 108.8 DC Volts

System environment:
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Stand alone SV8300 , CPU is CP00 with R7 software (SC-4081 J1-0005.01.00)
System consists of single CPU chassis and three expansion chassis

Beginning of the issue:
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More than 10 single line users reported their telephones were dead (no dial tone & no ring).
Digital telephones, CO trunk lines, TIE lines with the HQ SV8500, and Operator console all were working normally.

Actions taken:
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replacing the faulty LC cards with new ones solve the issue and all FAULTY extensions were restored to normal operation.

Measures taken for future safety and preventive reasons:
=====================================
Testing AC voltages found in the normal range (220~225)
Testing earth connection & tightening screws. all found OK.
Measuring extension line voltages on ALL RJ45 socket located in the LC cards , we found:
ABNORMAL readings (108.8) DC Volts on all the LC cards EXCEPT the reading of the first four extensions of the LC card located in "SLOT 04" it was measuring 26.6 DC Volts

Corrective actions taken:
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Removing ALL the RJ 45 connectors from the cards sockets ONE by ONE, and testing the extension voltage of the 1st four ports in SLOT 3 , same reading was noticed (108.8) DC Volts.
Removing all the cards; COT, DLC, and LC; one by one ((leaving only the LC card used for testing)) and measuring the extension voltage of the SAME 1st four ports in SLOT 3 ,same reading (108.8) was got.
Replacing the LC card used for testing with a NEW card, no reading changes were noted.
Initializing the pbx, and testing, same abnormal voltage.
Powering off two expansion chassis and disconnecting their BUSS cables, and measuring the voltage on the same card , same reading was noted.
Now , WHAT???
Should we have to replace the expansion chassis....!why not?
when the chassis #1 was replaced, voltage reading was NORMAL (26.6) DC volts,
less than 5 minutes later voltage reading was back to (108.8) volts.....!!! should we try another chassis?. we did try the new chassis but again with the same results...!
Finally we have nothing to replace BUT the CPU, and we did replace the CPU with a NEW one and loaded it with the system and office data and repeated the test, the reading was good BUT ONLY for 10 minutes this time...!
Did we forget to replace any thing else? for sure nothing was NOT replaced in the PBX....! and we still have the same abnormal voltage readings?
by the way we ALSO did not forget to use another volt
tester....!
Your help is very much appreciated.

I could not find a setting in the manual to switch over from 110v to 220v. If there is a switch setting, verify that all KSU's are set to 220v. Or, try to find a 110v source and move it over.

there is no issue with the AC source, the voltage reading here is measured on the RJ45 sockets located in the front side of the 8LCA cards it should be ~26 DC Volt but is is reading 108 DC Volts...Hope it is clear.

Have you tried cancelling message wait on all affected stations?

Hello R4+z, nice to see your post on board.
there were no waiting messages. NOT at all...!
By the way every thing is working normally EXCEPT the voltage readings, on one LC card located in slot 4, the first 4 ports measures ~26 Volt BUT the other 12 ports measure ~108 Volts...!!!!

Hi

Still lurking around but the forum seems to have shifted to SV8100s and to add insult to injury, I have not had too much exposure to SV8300s and 9x00s. Best bet would be the shelf as it would appear the shelf has a problem as you have swapped out the cards. How many shelves do you have? Can you try swapping one shelf for another and see if the problem stays with the hardware?

As said in my first post I replaced the shelf with a new one and that did not help, I have three expansion shelves and all LCs in these shelves give the same voltage reading (108.8) I do not think the three of them are faulty.

I can't see it being three faulty PSUs either but the only way I know of for the Volts to be up via software is message wait and you have excluded that. The only other thing common to the problem is the Voltmeter!

First I would check your meter to see if it's faulty. I had a Fluke go bad and it drove me nuts on a car battery once.

We didn't forget to try another voltmeter, also if it s the voltmeter why the reading of the first four circuits in the LC card located in Slot 04 is reading correctly 26 volt , please see my first post again.