DG S/130 progress

Jay West jwest at classiccmp.org
Wed Oct 14 17:07:55 CDT 2015

Henk wrote...

>Great series of pictures Jay!
Thanks! Most of those pics are "so I don't forget where wires go", but some
of them are presentable :)

>After more than a year on a desk, I mounted the 6125 tape drive in the top
of the rack with its power supply on the right side next to it.
I went to mount my 6125 today, but alas I may have to get creative. My 6125
was in a "desktop" stand, and when I remove the power supply and also look
at the DG Installation docs - it appears that they used a different sheet
metal backing to mount the 6125 in a rack (on the side, as you say) rather
than on the desktop unit. I was sooo hoping to just remove and mount. Well,
either they used different metal or my vertical posts are spaced different
than expected. I don't think it's the latter, because all the measurements
matched with the installation guide for the cpu and the 6030 disk unit.
Hummmm.. looking at pictures... it's the former. The sheet metal the PS is
mounted on is definitely shorter (left to right) on mine than what is
pictured. I guess I now have a use for the metal brake that I just bought
yesterday that is still in my car ;)

>Indeed!  I feel like being spoiled by DEC with connectors for everything.
Anything I would say to that would probably start a flame-war between DEC
and DG enthusiasts, so I'll just leave that one alone ;)

>I have the controller board for the 6125, but I do not have the cable from
the backplane to the paddle board. I *think* I do have the cable from the
paddle board to the pin header on the 6125 board (the horizontally mounted
As Bruce pointed out to me, there are actually only a few different
backplane wirings. Since it hasn't been rackmounted yet, I haven't gone
searching all the DG racks to see if I have any of the internal or external
or device cables for the 6125. We'll see. I suspect I will have to make all
my own cables; all my DG gear came from two collectors in separate
acquisitions - with one exception. This 6125 I bought off a shelf at the
local electronics haunt years ago, and it had no cables.

>My 6125 did power up correctly, but when I mount a tape and press BOT, it
spools some tape and then stops. When I press BOT again, it spools again
some tape. Did that a few times ... had to manually rewind the tape as
REWIND did not work. Could be a missing BOT on the tape, or issues ...
If there's no BOT tape on the tape, yeah. If there is, I'd look first at
testing the BOT/EOT sensor. I think there's a procedure for that in the
manual. ISTR that when it hits the BOT tape, it actually backs up a little
so it can get a "running jump".

>Keep posting!  I am a "newbie" on DG stuff with a long road ahead.
Ditto here, new to DG gear as well. Bruce has been a great help, but pouring
over docs for hours has been invaluable.



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