Dell External IBM LTO-5 Tape Drive error A

[ky56]

I bought a New Old Stock Dell IBM LTO-5 external tape drive from eBay 6 months ago. Up until 2 weeks ago it was working great. Now I can only write 1TB to 1.5TB Tapes at reduced speed and after a writing full tape it throws up error A on the SCD. According to the manual A means "Degraded Operation". But I'm not getting media or head errors. So what would that mean?

I have used a cleaning tape twice and cleaned the head manually with Isopropyl and cotton tips while being careful to not apply too much force or get any lint get caught in the head. The head looks in pristine condition as far as I know what they're supposed to look like.

I have run "Test Head" and "Test cartridge & media" tests and both pass. But it fails the "Write Performance" Test at 66MB/s instead of the 110/120MB/s I used to get. Using the IBM Diagnostic Software.

The only thing I can think of is that since this drive was NOS and probably sat in its box since Dec 2013 the lubrication has dried up somewhere related to tape head tracking and it preventing it from moving fast enough to maintain tracking.

[coromonadalix]

Never use cotton tips for a head clean up if its a rotating head like vcr ...  they leave some residues in the head gap

Cleaning head tape   sometime called a lapping tape is like an very fine sand paper, I never use this tape unless im in a dead end,    i clean the heads manually with proper cleaning pads,  ipa is generally good, but sometimes i must use stronger stuff

You have to see if the tape path is clogged or have stuck residues



could be as you wrote, some lubrification may be needed ?

[Rasz]

@coromonadalix LTO head doesnt rotate

[ky56]

On LTO drives in general. The head uses factory written servo tracks to precisely align the head vertically to the tape. On my version 5 drive there are 16 read write head elements and the tapes have 1280 tracks across 4 bands. The read and write heads switch operation in software depending of the direction the tape is moving. On IBM drives specifically the head uses a stepper for coarse movement and a voice coil for fine adjustment.

Since both media (Function E) and head (Function H) tests pass and the head visually looks new. The only other thing I can think of is something interfering with head tracking. Could be as simple as old dried up grease on the gears or dried up oil in the stepper. But this shouldn't be that much of a problem since it uses the voice coil for fine tracking. I'm reluctant to just go in have a go cause i'm fairly certain that if I stuff up the rotational head alignment it's finished.

The lack of info on why the "Write Performance" (Function F) test fails, the alert "Degraded operation" (TapeAlert A) appears yet the other tests pass is frustrating. Seems to be a rare failure type.

I was hoping that there might be someone on the forum who has experience with repairing computer data tape drives.

I am no professional or expert on this by the way. I'm just an amateur at home who loves mechanical and electrical engineering.

Drive Manual: ftp://ftp.software.ibm.com/systems/support/system_x_pdf/60y1487_english.pdf
More info:
https://www.lascon.co.uk/Tape-Linear-Technology.php
http://micha.freeshell.org/tape/Tech_LTO.html
https://www.theregister.com/Print/2013/09/19/history_of_magnetic_tape_part_two/ Specifically under "What's in store?" There is a diagram of wraps and head elements.
https://www.ltoultrium.com/lto-ultrium-roadmap/lto-the-technology-behind-the-media-pt2/

[ky56]

By the way if I do end up just disassembling it what grease would you recommend for the gears and what oil for the stepper motor, bearings and sleeve bearings? So far online I heard lithium grease and teflon oil.

[Rasz]

I seem to remember silicon grease was the thing to use.
LTO drivers are very similar to DLT