SL500 - Belisarius Card on IBM LTO 4 and IBM LTO 5 Can Short Out Disabling Card

Asset ID:	1-72-1533757.1
Update Date:	2017-09-25
Keywords:

Solution Type Problem Resolution Sure

Solution 1533757.1 : SL500 - Belisarius Card on IBM LTO 4 and IBM LTO 5 Can Short Out Disabling Card

Applies to:

IBM LTO5 Tape Drive - Version All Versions to All Versions [Release All Releases]
Sun StorageTek SL500 Modular Library System - Version Not Applicable to Not Applicable [Release N/A]
IBM LTO4 Tape Drive - Version All Versions to All Versions [Release All Releases]
Information in this document applies to any platform.

We have been made aware that there is a possible issue with the Digi Module on the Belisarius cards for IBM LTO4 and IBM LTO5 drives.
The issue is that there is a top and a bottom metal case on the Digi Module that snap together. Then a label is placed onto them and is used to help hold the case together. What is being found is that in rare scenarios the bottom of the metal case on the Digi Module can drop down, as a result of a small amount of pressure, and can short to traces on the Bel card. Please see picture -
We use an EMI shielded metal connector on the Ethernet cable in order to pass EMI certification. The cable shield intentionally contacts the case of the Digi Module. Thus if the case of the module comes into contact with the traces under the module, it is then possible to ground to the traces on the Bel.
The SL500 is the most susceptible to this issue since when a FE has to replace a drive they have no choice but to mess with the Ethernet cable and the Bel card to get them out of the way so that they can get to all of the connectors that need to be unplugged and plugged back in to the back of the drive. The Ethernet cable is so short on the SL500 trays that it has to be aggressively creased to allow it to go from the connector on the tray to the Bel card which in turn puts strain on the Digi chip and thus the bottom metal case on the Digi chip.

See Pictures IBM LTO 4
See Pictures IBM LTO 5

The Bel cards we have seen with this problem have behaved 2 different ways. In one failure the Encryption LED on the tray would never go off after a power cycle. In another failure the Green LED would not turn on after a power cycle. So far we have only seen this issue at one customer site running a SL500 although it was not physically verified via a full failure analysis – the Bel cards were scrapped locally.

If we become aware of any Bel issues escalated to us where the library is losing communication with the drive that we have the FE power up the drive in the tray and see if the green LED stays on and never goes out or the LED never comes on period and a physical inspection of the Bel card shows that the metal plate on the Digi Module is angled down and touching the Bel card then engineering would like those Bel cards to be sent back to them. This could be a Bel that is grounded. A Bel card should turn the LED on for approximately 30 seconds while the Bel IPLs after power is applied and then turn off.

Engineering is working with Guadalajara to see if we can get a temp fix in place and then they also are pushing IBM to put a permanent fix in place.
But for the time being we are going to have to handle these as one offs and see if we can get good Bel cards to the customer in a case by case scenario.
The one site that we know of that has seen symptoms of this problem on their SL500 has had 3 Bel failures but none were confirmed via FA to be this specific issue. The failure symptoms were pretty much the same from the drive side of things where the drive just stops communicating with the library. However depending on where the drive was in the library the symptom was different for how the library reacted to the hung Bel card. If the drive was in the base module and thus plugged in directly into the RLM card we saw where the library couldn’t be used and seemed to be hung. The local OP panel wouldn’t respond, the robot wouldn’t move and the FE couldn’t get on via SLC or the CLI port. Once the drive was pulled out the library came back to life and could be used. But if the drive was down in the Expansion module the library didn’t seem to be affected by the hung Bel card.

Symptoms

The Belisarius card on IBM LTO 4 and IBM LTO 5 can short out disabling card.

Cause

Metal shield on card can touch card frame if very little pressure is applied.

Solution

New releases of Belisarius are beiing given a insolator tape between frame and card.

Should this problem occur, the Belisaris card, PN 7065357, should be ordered to fix this issue as it has plastic tape fitted between the metal shielding and the solder points on the Belisarius card.

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