DEC RRD40 CDROM Drives

From: Clint Wolff <vaxman_at_qwest.net>
Date: Mon Apr 23 19:14:36 2001

Hi Zane,

I think the board he is talking about is a SCSI <==> audio CD
interface...

The original CD (not CD-ROM) interface is a three (or four) wire
affair with Left/Right, Clock, Serial data which is fed into
a DAC to produce music... The early CD-ROM drives took these
signals, recognized the sector header (00-FF-FF-FF-FF-00 IIRC)
and decoded the data. Presumably, some extra signals were added
to control seeking, etc...

I've got one of these boards, and I suspect the parts removed
were: 80C31, 27C256, and NCR 5380 (only parts socketted).

The drive is completely useless without these chips.

clint

On Mon, 23 Apr 2001 healyzh_at_aracnet.com wrote:

> No kidding, they'd have been interesting if not for that, since I'm assuming
> they're M7552 Q-Bus boards (which aren't really SCSI boards). :^(
>
> Zane
>
>
> > How is anybody going to use the boards if you have removed chips?
> >
> > Chad Fernandez
> > Michigan, USA
> >
> > Eric Dittman wrote:
> > > Also, the SCSI adapters are only for the
> > > RRD40 drives and I've removed the three
> > > ICs that are useful to me from each board.
> >
>
>
>
Received on Mon Apr 23 2001 - 19:14:36 BST