HP tape drive novel repair
jwest at classiccmp.org
Mon Jan 19 07:28:05 CST 2015
Im in the process of building another HP2000/Access TSB system. I pulled a
7970E tape drive out of a shipping container (I had not opened the shipping
container since I bought it about 8 years ago). When I got the unit on the
bench to give it a going over, while it looked pristine someone had
dropped something very heavy (heavy enough to severely deform ¼ steel) on
the top of the unit.
My thought (given theres not a shortage of open space inside the chassis)
was to put a car jack inside and jack it up thus pushing out the top. My
concern there was that there would be an equal and opposite reaction).
Perhaps a 2x4 that goes side to side under the jack would alleviate this.
But on freenode #classiccmp (where I hang out pretty much every night),
PJustice and Sark both had similar ideas for an alternative approach that
took advantage of the fact that the top of the chassis has a lot of vent
holes on top. I implemented their approach and it worked very well so I
thought Id document it with pictures and post here. I should note that this
approach only works because the angle iron I used was 14ga. Anything less
would just bend itself.
If I had facilities to cut the angle iron, I would have put a piece on top
and on the bottom but I dont. Failing that, I just had to pick specific
spots on top to pull out more carefully. As you know when steel bends it
stretches so it would be impossible to get it back 100% perfect but Im
pretty pleased with the results. If you want to use this method and dont
have convenient holes already present from the manufacturer, you could
always drill one or two holes to make it work. Note that without the wood
blocks you can pull it straight but it might bend back (albeit less so), but
with the wood blocks you can pull it further than straight so it bounces
back mostly straight.
And if you want to follow the build of the 2000/Access IO-rack (which holds
tape, terminal controller and bulkhead, and disk controller subsystem):
THANKS SARK AND PJUSTICE J
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