DECstation 5000/240 With the TURBOchannel Extender

Recently I repaired the H7826 power supply in my TURBOchannel Extender. So now I wanted to get it working with the DECstation 5000/240 it came with. The trouble is, I don’t have the cable to connect the Extender to the DECstation. However, I found a 100-pin SCSI cable that works for connecting the two enclosures.

The TURBOchannel Extender also has a SCSI connector for the disks and the CD-ROM Drive. To use the SCSI devices you have to connect a separate cable. The TURBOchannel Extender cable is just used for TURBOchannel cards. In messing around with the TURBOchannel Extender I found that if I install a PMAD (network interface) card in it, this seems to prevent any other card installed in the Extender from being recognised. I have not worked out why.

I have now configured the machine as follows. In the main DECstation enclosure I have installed a PMAG-D (actually upgraded to PMAG-E as it reports a 24-bit depth, the D is only 8-bit), and TURBOchannel Extender option. In the TURBOchannel Extender I have installed just the video capture card, which Ultrix does not recognise (not surprising as I think it is an experimental card), and the RRD42 CD-ROM drive and the two RZ25 drives that came with the machine.

Sadly the RRD42 does not seem to work. It will take in a caddy and eject it when I press the button, but I have been unable to use it to read any CDs. This will have to go on my list to look at some day.

I installed Ultrix 4.5 on one of the disks that came with the Extender. Sadly the other disk gives hard error if I try to install to that one. So I now have Ultrix 4.5 running on the DECstation, using the Extender as it was intended. The TURBOchannel Extender cable is a bit redundant though as the only TURBOchannel card in it is not supported by Ultrix. I have NetBSD 1.5.3 on a SCSI disk in a Storage Expansion enclosure, I can’t really put this disk in the Extender because it is too big.

Unfortunately I do experience intermittent startup problems. Sometimes the LEDs will indicate a “memory slot 0 could not be initialized” error. Cycling power seems to resolve this.

This entry was posted in Retro-Computing. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s