L700 - DLT7000 drive errors

Hi all,
our customer has a problem with TSM server and library SUN L700 (oemed STK
L700) with four DLT7000 drives - he can use only three drives in this
library. All four drives are defined on TSM server. One of them, does not
matter which one, must be manualy changed to status online=no. If four
drives are online, TSM server generate lot of error messages on drives -
write errors, read errors, locate errors, flush errors (approximately ten
messages per hour).
Does anybody have similar problem or environment?

TSM server 3.7.3 (IP21999) on Solaris 7
SUN StorEdge L700, F/W 2.00.00
4xDLT7000, F/W 95



type of messages:

ANR8302E I/O error on drive DRIVE1 (/dev/rmt/1mt)
(OP=WRITE, CC=306, KEY=03, ASC=0C, ASCQ=00,
SENSE=F1.00.03.00.00.00.00.16.00.00.F6.C3.0C.00.00.00.00-
.00.80.00.00.00.00.00.00.00.00.00.00., Description=Drive
or media failure).  Refer to Appendix B in the 'Messages'
manual for recommended action.

ANR8302E I/O error on drive DRIVE1 (/dev/rmt/1mt)
(OP=FLUSH, CC=422, KEY=03, ASC=80, ASCQ=01,
SENSE=F1.00.03.00.00.00.00.16.00.00.6F.9F.80.01.00.00.00-
.00.81.00.00.00.00.00.00.00.00.00.00., Description=An
undetermined error has occurred).  Refer to Appendix B in
the 'Messages' manual for recommended action.

ANR8302E I/O error on drive DRIVE3 (/dev/rmt/0mt)
(OP=LOCATE, CC=306, KEY=03, ASC=11, ASCQ=00,
SENSE=F0.00.03.00.00.6F.9B.16.00.00.00.04.11.00.00.00.00-
.00.87.00.00.00.00.00.00.00.00.00.00., Description=Drive
or media failure).  Refer to Appendix B in the 'Messages'
manual for recommended action.

ANR8302E I/O error on drive DRIVE1 (/dev/rmt/1mt)
(OP=OFFL, CC=208, KEY=0B, ASC=44, ASCQ=89,
SENSE=F1.00.0B.00.00.00.01.16.00.00.3B.85.44.89.00.00.00-
.00.81.00.00.00.00.00.00.00.00.00.00.,
Description=Command aborted).  Refer to Appendix B in the
'Messages' manual for recommended action.

ANR8302E I/O error on drive DRIVE1 (/dev/rmt/1mt)
(OP=READ, CC=422, KEY=03, ASC=80, ASCQ=01,
SENSE=F0.00.03.00.00.00.00.16.00.00.C9.CC.80.01.00.00.00-
.00.87.00.00.00.00.00.00.00.00.00.00., Description=An
undetermined error has occurred).  Refer to Appendix B in
the 'Messages' manual for recommended action.


Thanks.

Viliam Varga