At 05:32 PM 12/3/98 , Uzi Paz wrote:
>A strange thing.
>
>I have an external SCSI CD-R (Panasonic CW-7502B) which is connected to an
>Adaptec 2940AU SCSI controller.
>
>I also have an internal CD-ROM (Panasonic CR-588B)
>
>* If I physically connected the CD-R and SCSI card but the CD-ROM is
>  disconnected: the CD-R will be recognized correctly and will work fine.
>  (Both on DOS and on Win95)
>
>* If I disconnect the SCSI controller (and thus the CD-R) but connect the
>  CD-ROM, the CD-ROM will be recognized correctly and will work without
>  problems. (both on DOS and on Win95)
>
>* If I connect the SCSI adapter (PCI), and the CD-ROM (to the IDE2)
>  I will get a letter for the CD-ROM and if I try to access the CD-ROM it
>  will work but I shall always get that the CD-ROM drive does not have a
>  valid media. Also when looking at the drivers, the driver is claimed to
>  be loaded but to be attached to any drive. On DOS the drive letter will
>  not be assigned.


I can add some antidotal information from a personal experience recently.

I had a P200MMX system with a JVC SCSI 2x2 CD-R connected via
a generic SCSI3 adaptor in a system.  The system also had a BTC 24x
IDE CD Rom drive.   The CD-R drive became erratic, working properly
only occassionally.  Both drives were recognized by the system, but the
CD-R would create a great many error messages or create bad CD copies,
even with different CD writer software.

We replaced the CD-R drive with a new Panasonic SCSI 2X4 drive
and the problem persisted.   We switched out the SCSI adaptor and
still no luck.  We then disconnected the IDE CD Rom drive and the
CD-R worked fine.   So, we replaced the IDE CD Rom drive with a
new BTC 32x CD Rom drive.  The system has a new CD-R drive,
new SCSI adaptor and new CD Rom drive...    it works wonderfully.

I then put the old JVC CD-R and old SCSI adaptor into another machine
mated to a new BTC 32x cd rom drive.  They also work fine.  The old
24x BTC CD Rom drive was returned under warranty, (it was less than
12 months old) and the replacement drive has been received.

My conclusion is that the old 24X IDE BTC CD Rom drive went bad,  but
only in a fashion that caused it to no longer be compatible with a CD-R
drive.   It worked fine as a single CD Rom drive...   rather strange...
but, CD-R drives can be real difficult to diagnose.



Bob Wright  -   The NOSPIN GROUP
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