IBM Selectric II carriage return stuck

[Lee Kingston]

My IBM Selectric II typewriter fails to return the carriage when either the
Return or Exp key is pressed. I've taken the typewriter apart and have
gone as far as I can go with what I know. I'd sure appreciate any advice.
(Also, is there is a more appropriate group for this post?)

Here's what I've done so far:
Taking the typewriter roller, cover, and plastic guards off, I can see the
main drive axle, clutch spring, etc. There was some lube oil on the CR
clutch spring, so I cleaned that off. Turning the adjustment screw 1/2
turn, I very slightly adjusted the pressure foot under the clutch spring so
that there was no play in the movement, being sure that the foot is not
riding on the spring. I cleaned some old lube off the shaft that the CR
slides on and applied a slight bit of non-gumming turbine oil. As far as I
can see, everything should work, but it doesn't.

When pressing the Return or Exp key, the pressure foot stops the CR clutch
spring from spinning (no slippage); the drive gear to the right of the
clutch spring jerks and starts to turn the white gear that the CR twine and
wire is spooled on; tension increases on the CR wire; the carriage jerks
slightly on the sudden wire tension; but that's it. From the change in
sound, it sounds like a load is applied, but the carriage does not move.
So, it looks like either 1) the carriage movement is fine but the clutch is
not transferring enough power to the drive gear to pull the carriage to the
left, or 2) the clutch is fine but there is resistance somewhere affecting
carriage movement, creating a load that the CR clutch can't overcome.

Other than this carriage return problem, the typewriter works fine.
Pressing the tab key moves the carriage quickly forward; the backspace key
move the carriage quickly back; etc. Types and erases fine. No broken
parts that I can see.

Searching the web, I found this:
"Here are some of things that can cause return trouble;
Gummy or binding rtn link;
Gummy or binding tab linkage assmbly;
Gummy rtn latch;
Bad or worn rtn clutch;
Bad or worn rtn pinion;
Margin rack stuck or out of adjustment;
Rtn cluch/exp out of adjustment;
A very dirty carrier shaft;
or a combination of all the above."

I'm not a typewriter tech, so I don't know where to look for a "rtn link",
"rtn latch", "rtn pinion", "margin rack", etc.

Can anyone help me troubleshoot this problem? Thanks.

 

[Henry Mydlarz]

Lee,

I spent my first 15 years at IBM fixing these things, but am understandably
a bit rusty now (excuse the pun).

Operation of the carrier return clutch -

Pressing 'return' trips one of the two cams just on the right hand side of
the shaft. The cam operates an arm with a roller (the cam follower). That
arm is connected via a link to the carriage return shoe which presses
against the clutch spring. The clucth spring, which is fastened to the drive
part of the shaft with a clip, compresses and transfers the movement of the
drive shaft to the driven shaft which is geared to the white cable pulleys.
The cam follower arm stays latched until the carriage hits the left hand
margin bar, unlatching it.

I gather you can freely move the carriage manually from right to left, so
it's not the cables that have slipped off the carriage pulleys, or some
other obstruction.

From experience, the problem can be (1) the shoe gap being too far away from
the clutch, not exerting enough force. You can test that theory by gently
touching the driven part of the clutch spring, your finger acting as the
clucth shoe, to see if the carriage moves. (2) the clutch spring should have
absolutely no oil on it. Try flushing it with alcohol or some solvent. (3)
The spring could be worn (shiny) and slipping. That was a common problem (at
one stage we had a large batch of them in Australia which would wear out in
a matter of weeks. The proper thing to do would be to replace it. A quick
temporary way is to remove it and reverse it left to right. (4) the gap
between the drive pulley and the driven pulley (covered by the clutch
spring) should have a gap of no more than 2 thou. Any more and there is a
proportional risk of a clutch rung slipping into the gap.(5) the cam
follower roller could be worn. The roller should not have a groove where the
clutch cam contacts it (You guessed it - we had a faulty batch of those
too). That would mean that the shoe would not get enough motion to even
latch, let alone drive the shaft.

If you are a mechanical type person you may be able to repair it, however I
don't know how easy or hard it would be to get a new clutch spring. You need
special fluted Allan keys called 'Bristos' for all the screws. The procedure
for replacing a clutch spring is difficult if not impossible without a
manual. Replacing a follower arm or roller (there used to be a roller kit)
is a horror job, even with a manual.

Your best bet is to do as I suggested and first wash out the clutch spring
with alcohol, then touch the spinning free end of the return clutch to see
if that causes the shaft to drive (keep your finger clear of the clip at the
other end). Adjust the shoe links (I think the express backspace link is
under the machine, and the clutch link is at the end of the cam follower arm
behind the machine) for maximum application (minimum gap when not engaged.

I have manuals for this machine, but at present have no time to refer to
them. Please let me know how you go. If you like I will scan in the relevant
pages when I get a chance and email them to you.

Henry
Melbourne, Australia

"Lee Kingston" <SoundOp_TakeThisOut@Hotmail.com> wrote in message
news:Xns93E78F808668FSoundOpTTOHotmail@66.93.87.101...

My IBM Selectric II typewriter fails to return the carriage when either
the
Return or Exp key is pressed. I've taken the typewriter apart and have
gone as far as I can go with what I know. I'd sure appreciate any advice.
(Also, is there is a more appropriate group for this post?)

Here's what I've done so far:
Taking the typewriter roller, cover, and plastic guards off, I can see the
main drive axle, clutch spring, etc. There was some lube oil on the CR
clutch spring, so I cleaned that off. Turning the adjustment screw 1/2
turn, I very slightly adjusted the pressure foot under the clutch spring
so
that there was no play in the movement, being sure that the foot is not
riding on the spring. I cleaned some old lube off the shaft that the CR
slides on and applied a slight bit of non-gumming turbine oil. As far as
I
can see, everything should work, but it doesn't.

When pressing the Return or Exp key, the pressure foot stops the CR clutch
spring from spinning (no slippage); the drive gear to the right of the
clutch spring jerks and starts to turn the white gear that the CR twine
and
wire is spooled on; tension increases on the CR wire; the carriage jerks
slightly on the sudden wire tension; but that's it. From the change in
sound, it sounds like a load is applied, but the carriage does not move.
So, it looks like either 1) the carriage movement is fine but the clutch
is
not transferring enough power to the drive gear to pull the carriage to
the
left, or 2) the clutch is fine but there is resistance somewhere affecting
carriage movement, creating a load that the CR clutch can't overcome.

Other than this carriage return problem, the typewriter works fine.
Pressing the tab key moves the carriage quickly forward; the backspace key
move the carriage quickly back; etc. Types and erases fine. No broken
parts that I can see.

Searching the web, I found this:
"Here are some of things that can cause return trouble;
Gummy or binding rtn link;
Gummy or binding tab linkage assmbly;
Gummy rtn latch;
Bad or worn rtn clutch;
Bad or worn rtn pinion;
Margin rack stuck or out of adjustment;
Rtn cluch/exp out of adjustment;
A very dirty carrier shaft;
or a combination of all the above."

I'm not a typewriter tech, so I don't know where to look for a "rtn link",
"rtn latch", "rtn pinion", "margin rack", etc.

Can anyone help me troubleshoot this problem? Thanks.

 

[Lee Kingston]

Henry, thanks a lot for the reply.

Yes, the carriage moves right and left OK when using all keys that move the
carriage, other than the Return and Exp keys. The CR wire cable and nylon
twine have tension and are where they should be as far as I can tell;
(haven't seen anything off its pully). When pushing the carriage to the
left by hand, and then pressing the Exp key, the Exp key provides a little
"power assist", but that's all. Beyond an initial shudder from tension on
the CR wire, the Exp and Return won't move the carriage without a manual
push.

It looks to me like the clutch spring is not or is not fully transfering
the movement of the driven shaft to the gears that pull the CR cable.

Going through the potential problems you list:
(1) Shoe gap is OK. The Return and Exp keys, as well as a rubber tipped
instrument pressed manually against the clutch spring will stop the spring
from spinning. The drive gear on the main shaft, however, does not turn.
(2) I cleaned the little oil residue with alcohol. No change.
(3) The spring isn't shiny anywhere I can see it. As to slipping, I don't
know what Im looking for there. Using the Return key, Exp key, or manual
pressure the clutch spring stops spinning OK, with no slippage. The main
shaft continues spinning with no drag, but the drive gears to the right of
the clutch spring do not turn. With pressure applied, is it slippage of
the clutch spring that I am looking for? (if so, then there's no slippage)

To answer 4 and 5, can you further describe these parts so I'm clear on
what they are:
a) Driven pulley (covered by the clutch spring). (Is this the 90 degree
gear (black) on the main shaft just to the right of the clutch spring? I
know gears from pulleys, but I don't see any pulleys in the clutch spring
area.)
b) Drive pulley. (Is this the 90 degree gear (white) with the CR twine
wrapped on it?)
c) Gap between drive and driven pulleys. (where to look for this?)
d) Clutch rung. (?)
e) cam follower roller (?)
f) clutch cam (?)

On #5, I'm not sure what you mean by "latch" or "drive the shaft", but I
can say that when Return or Exp is pressed, the shoe does stop the clutch
spring from spinning. Pressure to the shoe appears OK.

Something else that might identify the problem:
In addition to the clutch spring that the shoe presses against, there is
another similar but larger spring to the left of the clutch spring clip.
This larger diameter spring has fewer wraps, is of sturdier build, and is
part of a larger assembly attached to the main shaft; the assembly appears
to have some adjustment (has "A", "B", "C" stamped on notches). When the
Return or Exp key presses the shoe against the smaller clutch spring, the
smaller spring stops spinning and so does the hub part inside the larger
spring. The larger spring continues spinning. Is that how it's supposed
to work?

Thanks for the clarification.



"Henry Mydlarz" <hemyd@optushome.com.au> wrote in
news:3f513ff3$0$6525$afc38c87@news.optusnet.com.au:

Lee,

I spent my first 15 years at IBM fixing these things, but am
understandably a bit rusty now (excuse the pun).

Operation of the carrier return clutch -

Pressing 'return' trips one of the two cams just on the right hand
side of the shaft. The cam operates an arm with a roller (the cam
follower). That arm is connected via a link to the carriage return
shoe which presses against the clutch spring. The clucth spring, which
is fastened to the drive part of the shaft with a clip, compresses and
transfers the movement of the drive shaft to the driven shaft which is
geared to the white cable pulleys. The cam follower arm stays latched
until the carriage hits the left hand margin bar, unlatching it.

I gather you can freely move the carriage manually from right to left,
so it's not the cables that have slipped off the carriage pulleys, or
some other obstruction.

From experience, the problem can be (1) the shoe gap being too far
away from the clutch, not exerting enough force. You can test that
theory by gently touching the driven part of the clutch spring, your
finger acting as the clucth shoe, to see if the carriage moves. (2)
the clutch spring should have absolutely no oil on it. Try flushing it
with alcohol or some solvent. (3) The spring could be worn (shiny) and
slipping. That was a common problem (at one stage we had a large batch
of them in Australia which would wear out in a matter of weeks. The
proper thing to do would be to replace it. A quick temporary way is to
remove it and reverse it left to right. (4) the gap between the drive
pulley and the driven pulley (covered by the clutch spring) should
have a gap of no more than 2 thou. Any more and there is a
proportional risk of a clutch rung slipping into the gap.(5) the cam
follower roller could be worn. The roller should not have a groove
where the clutch cam contacts it (You guessed it - we had a faulty
batch of those too). That would mean that the shoe would not get
enough motion to even latch, let alone drive the shaft.

If you are a mechanical type person you may be able to repair it,
however I don't know how easy or hard it would be to get a new clutch
spring. You need special fluted Allan keys called 'Bristos' for all
the screws. The procedure for replacing a clutch spring is difficult
if not impossible without a manual. Replacing a follower arm or roller
(there used to be a roller kit) is a horror job, even with a manual.

Your best bet is to do as I suggested and first wash out the clutch
spring with alcohol, then touch the spinning free end of the return
clutch to see if that causes the shaft to drive (keep your finger
clear of the clip at the other end). Adjust the shoe links (I think
the express backspace link is under the machine, and the clutch link
is at the end of the cam follower arm behind the machine) for maximum
application (minimum gap when not engaged.

I have manuals for this machine, but at present have no time to refer
to them. Please let me know how you go. If you like I will scan in the
relevant pages when I get a chance and email them to you.

Henry
Melbourne, Australia

 

[Henry Mydlarz]

Sorry Lee. I told you I was rusty. As well as that I think Alzheimers is
getting to me. Yes, they are really gears, not pulleys. If you put pressure
on the end of the clutch while the drive shaft is moving the spring should
not stop spinning, but transfer the drive to the other part of the shaft.
The spring clutch must be secured to one end of the shaft (I think the right
end) by a sort of a clamp. On the right hand side of the shaft are two large
cams which do a full revolution when they are tripped. One is the spacebar
cam; the other is the carriage return/index (linespace) cam.

I have not been able to find my manuals. When I get around to it in the next
day or so I'll grab my old selectric and take a digi photo, label everything
and email it to you. If the spring stops turning when you apply pressure to
it, then it must be either that the securing clamp on one side of the spring
is missing, or the spring is broken. I'll really get off my bum and send you
a photo.

Henry

"Lee Kingston" <SoundOp_TakeThisOut@Hotmail.com> wrote in message
news:Xns93E7C2725D638SoundOpTTOHotmail@66.93.87.101...

Henry, thanks a lot for the reply.

Yes, the carriage moves right and left OK when using all keys that move
the
carriage, other than the Return and Exp keys. The CR wire cable and nylon
twine have tension and are where they should be as far as I can tell;
(haven't seen anything off its pully). When pushing the carriage to the
left by hand, and then pressing the Exp key, the Exp key provides a little
"power assist", but that's all. Beyond an initial shudder from tension on
the CR wire, the Exp and Return won't move the carriage without a manual
push.

It looks to me like the clutch spring is not or is not fully transfering
the movement of the driven shaft to the gears that pull the CR cable.

Going through the potential problems you list:
(1) Shoe gap is OK. The Return and Exp keys, as well as a rubber tipped
instrument pressed manually against the clutch spring will stop the spring
from spinning. The drive gear on the main shaft, however, does not turn.
(2) I cleaned the little oil residue with alcohol. No change.
(3) The spring isn't shiny anywhere I can see it. As to slipping, I
don't
know what Im looking for there. Using the Return key, Exp key, or manual
pressure the clutch spring stops spinning OK, with no slippage. The main
shaft continues spinning with no drag, but the drive gears to the right of
the clutch spring do not turn. With pressure applied, is it slippage of
the clutch spring that I am looking for? (if so, then there's no
slippage)

To answer 4 and 5, can you further describe these parts so I'm clear on
what they are:
a) Driven pulley (covered by the clutch spring). (Is this the 90 degree
gear (black) on the main shaft just to the right of the clutch spring? I
know gears from pulleys, but I don't see any pulleys in the clutch spring
area.)
b) Drive pulley. (Is this the 90 degree gear (white) with the CR twine
wrapped on it?)
c) Gap between drive and driven pulleys. (where to look for this?)
d) Clutch rung. (?)
e) cam follower roller (?)
f) clutch cam (?)

On #5, I'm not sure what you mean by "latch" or "drive the shaft", but I
can say that when Return or Exp is pressed, the shoe does stop the clutch
spring from spinning. Pressure to the shoe appears OK.

Something else that might identify the problem:
In addition to the clutch spring that the shoe presses against, there is
another similar but larger spring to the left of the clutch spring clip.
This larger diameter spring has fewer wraps, is of sturdier build, and is
part of a larger assembly attached to the main shaft; the assembly appears
to have some adjustment (has "A", "B", "C" stamped on notches). When the
Return or Exp key presses the shoe against the smaller clutch spring, the
smaller spring stops spinning and so does the hub part inside the larger
spring. The larger spring continues spinning. Is that how it's supposed
to work?

Thanks for the clarification.



"Henry Mydlarz" <hemyd@optushome.com.au> wrote in
news:3f513ff3$0$6525$afc38c87@news.optusnet.com.au:

Lee,

I spent my first 15 years at IBM fixing these things, but am
understandably a bit rusty now (excuse the pun).

Operation of the carrier return clutch -

Pressing 'return' trips one of the two cams just on the right hand
side of the shaft. The cam operates an arm with a roller (the cam
follower). That arm is connected via a link to the carriage return
shoe which presses against the clutch spring. The clucth spring, which
is fastened to the drive part of the shaft with a clip, compresses and
transfers the movement of the drive shaft to the driven shaft which is
geared to the white cable pulleys. The cam follower arm stays latched
until the carriage hits the left hand margin bar, unlatching it.

I gather you can freely move the carriage manually from right to left,
so it's not the cables that have slipped off the carriage pulleys, or
some other obstruction.

From experience, the problem can be (1) the shoe gap being too far
away from the clutch, not exerting enough force. You can test that
theory by gently touching the driven part of the clutch spring, your
finger acting as the clucth shoe, to see if the carriage moves. (2)
the clutch spring should have absolutely no oil on it. Try flushing it
with alcohol or some solvent. (3) The spring could be worn (shiny) and
slipping. That was a common problem (at one stage we had a large batch
of them in Australia which would wear out in a matter of weeks. The
proper thing to do would be to replace it. A quick temporary way is to
remove it and reverse it left to right. (4) the gap between the drive
pulley and the driven pulley (covered by the clutch spring) should
have a gap of no more than 2 thou. Any more and there is a
proportional risk of a clutch rung slipping into the gap.(5) the cam
follower roller could be worn. The roller should not have a groove
where the clutch cam contacts it (You guessed it - we had a faulty
batch of those too). That would mean that the shoe would not get
enough motion to even latch, let alone drive the shaft.

If you are a mechanical type person you may be able to repair it,
however I don't know how easy or hard it would be to get a new clutch
spring. You need special fluted Allan keys called 'Bristos' for all
the screws. The procedure for replacing a clutch spring is difficult
if not impossible without a manual. Replacing a follower arm or roller
(there used to be a roller kit) is a horror job, even with a manual.

Your best bet is to do as I suggested and first wash out the clutch
spring with alcohol, then touch the spinning free end of the return
clutch to see if that causes the shaft to drive (keep your finger
clear of the clip at the other end). Adjust the shoe links (I think
the express backspace link is under the machine, and the clutch link
is at the end of the cam follower arm behind the machine) for maximum
application (minimum gap when not engaged.

I have manuals for this machine, but at present have no time to refer
to them. Please let me know how you go. If you like I will scan in the
relevant pages when I get a chance and email them to you.

Henry
Melbourne, Australia

 

[Henry Mydlarz]

Hello Lee,

You may want to inspect a twin-spring loaded pulley (yes - pulley) around
which goes the right hand carrier cable. It is just outside the right hand
frame, just above the shift cam assembly. The plastic bracket on which the
pulley is mounted is notorious for cracking and breaking.

Henry

"Lee Kingston" <SoundOp_TakeThisOut@Hotmail.com> wrote in message
news:Xns93E867C1BA8ACSoundOpTTOHotmail@66.93.87.101...

Henry,

From my original post:
"So, it looks like either 1) the carriage movement is fine but the clutch
is not transferring enough power to the drive gear to pull the carriage
to the left, or 2) the clutch is fine but there is resistance somewhere
affecting carriage movement, creating a load that the CR clutch can't
overcome."

Because there was tension on the CR wire when I pressed Return or Exp
(showing that the clutch was trying to pull the carriage), I decided to
work some more on the #2 possibility, and instead of just lubricating the
main carriage shaft, I lubricated absolutely every surface that looked
like it could possibly come in contact with the carriage (front and
back). I worked the carriage manually back and forth, and let the thing
set overnight. Well, something loosened up, and the Return and Exp keys
now will return the carriage without a manual push. The CR action is
dragging a bit and not real smooth, so there still must be some lube
points I missed.

Can you recall the details regarding critical lubrication points for
carriage movement?

While I've got the oil bottle in my hand, what else should I lube while
I've got the typewriter cover off? (I'm using non-gumming turbine oil
(paraffin based); I'm pretty sure that's OK to use on a Selectric. I
also have white lithium grease (petroleum based); not sure if that's OK.)

Thanks.

Lee

(PS: Clutch spring clamp is there and OK, located on the left side of the
clutch spring.)


"Henry Mydlarz" <hemyd@optushome.com.au> wrote in
news:3f517f6c$0$6526$afc38c87@news.optusnet.com.au:

Sorry Lee. I told you I was rusty. As well as that I think Alzheimers
is getting to me. Yes, they are really gears, not pulleys. If you put
pressure on the end of the clutch while the drive shaft is moving the
spring should not stop spinning, but transfer the drive to the other
part of the shaft. The spring clutch must be secured to one end of the
shaft (I think the right end) by a sort of a clamp. On the right hand
side of the shaft are two large cams which do a full revolution when
they are tripped. One is the spacebar cam; the other is the carriage
return/index (linespace) cam.

I have not been able to find my manuals. When I get around to it in
the next day or so I'll grab my old selectric and take a digi photo,
label everything and email it to you. If the spring stops turning when
you apply pressure to it, then it must be either that the securing
clamp on one side of the spring is missing, or the spring is broken.
I'll really get off my bum and send you a photo.

Henry