18 Apr
2021
18 Apr
'21
10:40 p.m.
From: Fritz Mueller
I'm reassembling an PDP-11/34 in a BA11-K chassis
right now, and am a
little puzzled by the front mounting brackets (the ones that hold a
KY11-L of either sort on the bottom, and a half trim-panel on the top).
In particular, on the bottom half, the available place for screws to go
to attach the bracket to the chassis is nearly completely blinded by an
overhanging tab.
..
Anybody have an 11/34 in a BA11-K and care to take a peek and tell me
how the hardware here is properly configured?
Well, I have an KY11-LA mounted on a BA11-K; the KY11-LA and -LB use the
same bezel, and should have identical hardware.
There's an intermediate 10" or so high adapter piece (one either side, of
course) mounted to the KY11-L. (That's attached to the KY11-L with short
machine screws which are inserted from the rear, and go into tapped holes in
the KY11-L bezel.) That piece attaches to the BA11-K with different hardware
at the top and bottom: on the bottom, a single 1" or so machine screw (#8, I
think) goes through the vertical tab on the side at the front of the BA11, to
a tapped hole in the adapter piece. At the top, a pair of short countersunk
machine screws (#10, I think - definitely larger than the 1" machine screw at
the bottom) attach a pair (one each side) of those black plastic mounting
widgets which have a pair of balls on stalks; those go into holes on the back
of the blank panels, and those screw also hold the adapter piece to the
BA11-L at the top. (I looked for the DEC formal name for those pieces, but
couldn't find it.)
I'll get some pictures of the brackets I have, too
-- maybe they aren't
the standard/correct ones for an 11/34...
I'll take a look. I'm too burned out (COVID long haul) at the moment to take
pictures or do a drawing right at the moment; if needed, I can do it tomorrow
(or so).
Noel
PS: A while back you were after measurements on the KY11-L power knob;
did you ever get those: If not, I've got one, and can measure it.
19 Apr
19 Apr
1:45 a.m.
On Apr 18, 2021, at 7:40 PM, Noel Chiappa <jnc at
mercury.lcs.mit.edu> wrote:
There's an intermediate 10" or so high adapter piece (one either side, of
course) mounted to the KY11-L... on the bottom, a single 1" or so machine screw (#8,
I think) goes through the vertical tab on the side at the front of the BA11, to a tapped
hole in the adapter piece.
Thanks for the details, Noel!
Pictures of my brackets should be viewable at https://photos.app.goo.gl/wni3mDAQHozK9Ho27
The interesting/confusing bit for me is the bottom part... In the second picture you can
see that my brackets just have a punched oval hole at the bottom, and not a "tapped
hole" per your description above. The tabs on the chassis to which these brackets
mount all have #10 press fit threaded bushings.
The bit at the top, with the plastic pieces (called out on the parts lists as "latch,
molding") and countersunk #10 screws is clear, and looks like what you describe.
I'll take a look. I'm too burned out (COVID
long haul) at the moment to take
pictures or do a drawing right at the moment; if needed, I can do it tomorrow
(or so).
Something a lot of us are going to have to face in the upcoming months/years, it seems --
wishing you best!
PS: A while back you were after measurements on the
KY11-L power knob;
did you ever get those: If not, I've got one, and can measure it.
I did not get exact measurements, however, I did find this part:
https://www.millsupply.com/knob-fan-speed-grumman-olson-53777.php?p=324629
...which turns out to be a very suitable replacement: bezel diameter and post height are
just right, marking lines up nicely with the panel, good feel and very sturdy.
cheers,
--FritzM.
3:38 a.m.
Apparently DEC redid their design; my entire assembly is quite different and
"it just works". I imagine that you aren't the first to be flummoxed by
their original design.
In my6 case there is no bump-out sub-assembly spot-welded to the plate,
instead there is a separate wide-flat U bracket where the ends attach
above/below to the plate (which is threaded) and the middle attaches forward
to the console (which is threaded). The wide-flat U bracket is first
attached to the flat-plate (chassis in any position). The flat-plate has a
wide notch aligned with the attached wide-flat U bracket center to allow the
console to be screwed in from the back (chassis necessarily extended). The
3-U filler panel is attached with Velcro to the flat plate; no ball-breaking
required :->.
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Fritz
Mueller via cctalk
Sent: Monday, April 19, 2021 1:45 AM
To: General Discussion: On-Topic and Off-Topic Posts
Cc: Noel Chiappa
Subject: Re: DEC BA11-K KY11-L mounting brackets -- how?
On Apr 18, 2021, at 7:40 PM, Noel Chiappa <jnc at
mercury.lcs.mit.edu> wrote:
There's an intermediate 10" or so high adapter piece (one either side, of
course) mounted to the KY11-L... on the bottom, a single 1" or so machine
screw (#8, I think) goes through the vertical tab on the side at the front
of the BA11, to a tapped hole in the adapter piece.
Thanks for the details, Noel!
Pictures of my brackets should be viewable at
https://photos.app.goo.gl/wni3mDAQHozK9Ho27
The interesting/confusing bit for me is the bottom part... In the second
picture you can see that my brackets just have a punched oval hole at the
bottom, and not a "tapped hole" per your description above. The tabs on the
chassis to which these brackets mount all have #10 press fit threaded
bushings.
The bit at the top, with the plastic pieces (called out on the parts lists
as "latch, molding") and countersunk #10 screws is clear, and looks like
what you describe.
...
cheers,
--FritzM.
1195
days inactive
1195
days old
2 comments
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participants (3)
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fritzm＠fritzm.org -
jnc＠mercury.lcs.mit.edu -
pbirkel＠gmail.com