120A CSU Test Issue

[Avayatech714]

Here a good one I hope someone can figure out for me.

Here is a puzzling on for you.

We have a Prologix test switch running R9.5 (had Echo Cancellation turned on and 5 RTU for NC boards turned on) we use this switch to test various CPs but have been testing 1000s of 120A CSUs for the past few years - no problem. We have a TN464F in Slot 10. We always have the board busied out - we disengage it from the slot - put the test 120ACSU on the back AMP50 connector and connect the Loopback jack to it. Re-insert the DS1 board and then run the DSI loopback test on the CSU. It will light up the LBJ and then show PASSED in the test results.

We also use this #10 slot to test our DS1 packs. So we got in a TN464HP pack and were testing it ... we connected our lab test 120A2 CSU to the cabinet and ran the LBJ test first and it passes then run the test DSI board 01A10 Long test and it passes. Ok - TN464HP is working.

But my tech decides to test a few 120A 4 -5 & 6 CSUs while the TN464HP is still in the cabinet. He disengages the DS1 pack - puts the first 120A4 on the back connector and the 120A4 passes the LBJ test fine. Then he tests a A5 & A6 CSU and they both light up the LBJ for 15 seconds or so then go out and the test fails??? We don't think the CSUs are bad as we removed them from a MCC cab we just got in directly out of service.

So we swap out the TN464HP w/ our normal TN464F test DS1 board and both the A5 & A6 CSUs pass the LBJ test. We swap back the TN464HP and they both fail. Then we get curious and test them with a TN464GP - they both fail - but 120A2s-3s & 4s pass fine with the GP.

So we are really scratching our heads as all the CSUs pass on the Tn464F but the 5s & 6s fail on the HP & GP. We think it might be some type of echo cancellation conflict - even though I have sold 100s of GP & HPs with 120A 6s and never had one come back. I turned off the echo cancel option on the switch and reset the EC boards to 0 - saved trans and reset SYS 4 and the problem continued. So it wasn't that issue.

Any ideas?

 

[Mitch672]

just a SINGLE bad 120CSU can blow the fuse on the DS1 circuit pack, it's a surface mount fuse, and I have replaced them many times. If you are getting no LED's, and the 120CSU seems dead, it's probably because you have a blown fuse on your DS1 card.

I have bought the fuzes from DigiKey, and they are fairly large, so with just solderwick and a decent soldering iron, the fuse can be replaced.



Mitch

AVAYA Certified Expert

 

[Avayatech714]

M. We always check the fuses on the DS1 boards in our repair lab and know that issue but if you read the post I left - it definately isn't a bad CSU or DS1 board as all the CSUs A2 thru A6 test fine on the TN464F but only the 120A2-Thru A4s test good on the GPs & HPs. The 5s & 6s won't pass on the GPs-HPs but do on the F.

Strange issue.

 

[4merAvaya]

Are you running the most-current firmware (FW24) on the TN464GP & TN464HP?

Kevin

 

[Avayatech714]

Is that a requirement for A5s & A6s to work properly on the GPs & HPs? Never heard that before? Is that in an Avaya tech bulletin?

 

[4merAvaya]

Don't know. Is it worth trying to see if it solves the problem?

Kevin

 

[Avayatech714]

Sure - we will try anything - but why do the A5 & A6 test fine on the older TN464Fs?