On Tue, 4 Jun 2002, Dwight K. Elvey wrote:
> Hi
> Look at the wiring. If it looks similar to what is on the other
> 25L6's, you should be OK. You should check the grid voltages
> on all of these tubes. Incorrect bias can cause excess plate
> disapation. This will shorten the tube life to minute/hours.
> See below for pinout:
>
> http://www.nostalgiaair.org/scripts/showbase.dll?TYPE=25L6&BASE=7AC
>
> later
> Dwight
This is excellent advice; however, it assumes a certain inventory of
skills/equipment on the part of the Owner. Barring Sellam's learning a
lot of obsolete elctronic lore and basic tube theory, and then dredging
the chassis out of the pedestal and going thru the wiring and voltages -
what he asked for (and what is the needed info in this case) is:
^^^^^^^^^^^^^^^^^
* What is the tube layout for the 026 Printing Punch electronic chassis? *
One tube is missing; the rest are 25L6s (IBM Badged, no less!) and we
have no 'docatall' for the rig. Therefore, anyone with the correct tube
layout info is encouraged to post it here so that Sellam may fill the
8-pinned, stem-keyed, lonely socket where once a Happy Tube lived and
worked.
The electronic symptom is (for those familiar with the circuit): The
majority of the keys, when depressed, do not seem to perform any
functions, and do not release afterward (they stay depressed). Depressing
the Master Clear under the Read Station clears the machine and releases
the keys. The REL key and (IIRC) the SKIP key do their thing - nothing
else. When prodded manually, the machine feeds cards, and has, from time
to time, tried to DUP punch, but it's severly autistic in it's current
state of repair.
I recall the missing tubels position as being the lower row of tubes,
far left one, when veiwing the chassis in it's normally-installed
position.
That's all I could glean from a pleasant Sunday morning of minor
disassembly, cleaning, oiling, and general TLC. It sat in a garage for
several years, and gathered much dust. Now, it cries out for life! Life!
Life after Scrap!
>
>
>
> >From: "Sellam Ismail" <foo_at_siconic.com>
> >
> >
> >So I'm off to look for a 25L6 tube for my IBM 026. John Lawson says that
> >the tube is a 25L6 because all the other tubes in the rack are 25L6 types
> >and he believes they are hammer drivers. Not to doubt the venerable
> >Mr. Lawson, since he did used to service these,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Minor correction For The Record: I punched my share of cards on various
026s, got in trouble in high school for getting caught by the Math Dept
Head with the covers all off one of the ones we had there (investigating
it's beautiful complexity, nothing more..), used shopping bags full of
chads for illicit confetti, but I never actually made my living keeping
'em punching. Roads not taken...
> >but I just want to make
> >sure this is in fact the right tube type that goes into the socket that is
> >currently empty. See photo here:
> >
> >http://www.vintage.org/gallery.php?title=IBM%20026%20Printing%20Card%20Card%20P
> unch&grouptag=IBM026
> >
> >I'd hate to plug in the wrong tube and then witness volumnious
> >amounts of smoke billow from within the machine. Can someone verify that
> >the 25L6 is indeed the correct tube for the empty socket?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> Note required information. Bottom left-most tube, IIRC. <-
Cheers
John
Received on Tue Jun 04 2002 - 21:19:33 BST