SD_WILSON

I hate to be the one to say this but I think you are dreaming. Nortel wants you to buy replacement cards - they jealously guard their schematics and circuit diagrams. I think there are places that refurbish phones by cleaning them and making minor repairs but I don't know anyone who makes repairs at the board level. If cost is an issue try the 2nd hand and refurbish sites on the internet, that will ikely be cheaper than the effort it will take to troubleshoot and repair defective cards - especially 2 sided multi-layer surface-mount. I think your company is still thinking in terms of the 60s' - 80's electronics repair when it was cheap and easy to get parts and make repairs.

We have over a thousand cards installed on site and we have a failure rate of less than one a year. If you have several defective cards you may want to check the grounding on your switch.

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gwebster

SD is correct. Nortel only releases schematics and bill-of-materials to authorized repair centers. These are multi-layered, double-sided surface mount, dense circuit packs. Not only do you have to diagnose the fault, but you have to have access to replacement parts, the tools to actually replace the part, firmware files as required to load into the processors on the boards, as well as a test jig to confirm that the board has been repaired.

The Mean Time Between Failure of circuit packs are given in the NTP and - in most cases - are measured in decades. If you are having a significant number of failures, an investigation should be undertaken.

Are you using the Analog Message Waiting Line Cards to provide service to phones at a distance from you Meridian 1 (the lines leave your building and are thus susceptible to lightning strike)?

michael_zheng

Thank you, SD and gwebster.

I showed those messages to my boss, it seems he changed his mind, or he is going to change it. Anyway, it makes my life a little bit easier.

gwebster, we don't have any lines out of the building. So, lightning strike won't be a problem. Still thanks, this is a good angle to think about this problem. Right now, I am checking the grounding and other possible shorten.