[GreenKeys] Refurbishing a 33 KSR

[Don Robert House]

Hi Chris,

I will ask my webmaster to put the scanned 33 training manual up on my
website.  Take a look at the site you have not already done so.  Some of
the images are messed up, but there is a lot of information there.

http://www.nadcomm.com/

Most people have a lot of trouble with 32 and 33 keyboards because they
remove the unit to work on it.  I used to do that but is not a good  
idea...

Here is how you do it...

With the cover off the rest of the machine you will notice two C rings,
one on each side of the plastic keyboard top. Remove thesed with a pair
of pliers. Be careful not to loose them. Then make sure the two mounting
screws holding the keyboard in place are nice and snug.  Do not remove
the so-called "H Lever" which is actually an "X".  The H-Lever is what
trips the distributor to serialize the parallel data coming from the
keyboard, the answer-back drum, and/or the tape reader if an ASR. All
of those contacts are in parallel.  If one bounces it garbles the other.

Take a wide flat screwdriver, or preferably an old butter knife and
pull the right side metal frame away from the plastic "tits" that
protrude through the frame and lift.  This makes it a bit easier to pry
the left frame away from the left side "tits." Remove the plastic cover.

You will now notice that the keys alternate from being held in the front
and held in the back with the opposite end of each key lever being loose
in a slot.  Using a long nose pliers SLIGHTLY bend the horizontal frame
rectangle that holds the key lever you want to change the keytop on.

Wiggle the keytop with its key lever until it pulls up and out. Take the
key lever to a strong vice and put the lever in the jaws of the vice.
Then use your long nose pliers as a double lever to remove the unwanted
keytop.  Once it comes off. (Some can be difficult) you can put the key
top you want on the lever.  Make sure the vise is tight and use a small
flat piece of wood, such as a tongue depressor, to cover the top of the
key top while you tap it down with a tack hammer or wood hammer.

The only keys you have to be careful of are the HERE IS key and the
REPEAT key as they are only loosely held in place with their springs
by rectangular holes in the frame.  When you have completed your
desired keytop changes you simply reverse the procedure starting from
the left side. Use the eraser on the end of a pencil to align any key
tops that are not falling into place as you lower the keyboard top into
place,

You will be pleased when you get done.  I replaced the O with the
arrow with the O with the underscore on my 35ASR so I could send
you this keytop. However the keytops I removed are less than perfect.
Paul Cembura has most of the keytops and they are all new old stock.

Best,
Don
K9TTY


On 31 Jan 2011, at 12:26 PM, Christian Gauger-Cosgrove wrote:

Hello,

I would quite enjoy having a set of manuals, only problem is the manual
set on eBay (the one I found, and I think the one you were referring to)
I personally cannot purchase. (Yay for not having a PayPal account at
all.)

The training manual could provide an interesting read. (Also, why not
put the PDF on BitSavers if you do end up scanning it. Let the whole
world get a chance to read it.)

As one person told me when I asked about the keyboard "don't touch it
as it is filled with a great many parts that have a tendency to go  
'sproing'
and fling themselves to the other end of the room." Where could one get
a replacement type wheel though? I ask because I personally find I like
ASCII '63 compared to later ASCII variants; plus every DEC manual that
mentions the teletype and software involving the teletype, is based on
ASCII '63 which has the up arrow and left-pointing arrow.

That fix for the print hammer doesn't sound all too difficult. I'll  
end up
doing it as soon as I get some spare time and money to buy some tubing
(I also need some spare time and money to get the rest of the TTY
working too).

I have some photographs of the KSR-33's I/O cables, and I can provide
them if you're interested as I'm still trying to figure out what the
interface actually is. Because I'm not wholly sure at all.

Thanks for the help, and cheers to you.



On 31 January 2011 00:08, Don Robert House wrote:

Christian,

A set of manuals would be helpful for you to figure these things out.
There is a nice five volume set up for bids on eBay.

I also have a 33 training manual here I could scan and send to you.
I am not sure when I will have time to do it yet however.

There were at least a dozen different type wheels and the keytops
were not always changed to match.  Changing keytops on a 32 or
a 33 is a bit of a challenge.

The best print hammer is a piece of 7/16 inch vinyl tubing cut to
7/8 inch long.  Warm it in your hands and push it over the print
hammer after cleaning the gunk off.

The 33 was made in different configurations depending on the
interface that was needed. Some have an EIA interface and some
have a 20 Milliamp current interface.

Good luck...
Don
K9TTY



On 30 Jan 2011, at 10:51 PM, Christian Gauger-Cosgrove wrote:

Right, well hello everyone.

I need a bit of help figuring out what - in general - could be
the problem with my KSR-33 teletype, and what I could do to get
it back to the point of actually working. I'll quickly list and
describe the problems that affect the KSR-33.

Firstly, and this problem cropped up most recently. While running
the teletype to check something regarding it; I noticed the teletype
had begun to make an odd noise, before I could kill the power, the
main drive motor blew it's fuse. On a whim - and at the suggestion
of a person who shall remain nameless - we popped a spare fuse in
to check to figure what the problem could have been. Unsurprisingly,
the second - new - fuse blew in a very short time; however the odd
noise seemed to have disappeared.

Secondly, and the teletype has had this problem since I got it, is
that the carriage will not move at all. Though I am unsure if that
is completely correct, as the carriage is at the furthest point
rightward in it's travel, and therefore cannot proceed right any
further. But it also will not return to the left.

Thirdly, the rubber part of the print hammer is completely vanished
into nothingness. But luckily I'll be making a stop at Home Depot
sometime in the near future, so that issue will be resolved quite
shortly.

Fourthly - and this issue is not all that pressing until everything
else has been fixed - but I have no idea what the connection for
the input/output of the teletype is. I say this because the connector
isn't what I ususally assumed was a current loop connection. But
the connector - which is a male DB-25 connector - doesn't seem to
have enough of it's pins connected to the cable to the teletype to
make sense as an RS-232C serial connection. (However, the giant
brick of a box made by "UTEC" looks like it could be a current loop-
to-RS232 converter, so that may be the solution to that.)

I've already downloaded - and paged through - the manuals for the
machine that are on BitSavers. Though I do find them somewhat
impenetrable.

Oh, and as a question; were the type cylinders of all Model 33 teletypes
the same throughout their production lifetime? Or did they ever change
the type cylinders? I ask because the keyboard of my KSR-33 has replaced
the up-arrow and back arrow-symbols with the caret and low-line ASCII
symbols. Would that mean that the type cylinder of my KSR-33 has those
ASCII characters on it as opposed to the arrows? Or is the cylinder
always the same? If the type cylinders are different, how difficult
would it be to get a Model 33 type cylinder with the "original"
character set?

Two final queries; firstly, what kind of ink ribbon does the Model 33
teletype use, and where can one find a replacement ribbon? Secondly,
Is it possible to use 8.5" roll paper with an inner core diameter of 2"
instead of 1" when replacing the paper roll?

In conclusion to this rather long, and very rambling e-mail I look
forward to any replies to my questions, and any suggestions as to what
I could do to get my KSR-33 back up and running again.

Thanks in advance,
C. M. Gauger-Cosgrove