ASR-33, was Re: DEC VT05 with OS/8 -- basic system rebuild?

[Tony Duell]

[ASR33]

>    It has an annoying issue with carriage return...If a CR is  
> received, and if the print mechanism hasn't moved far enough to the  
> right for the return action to build up enough momentum, friction  
> causes the carriage to stop before it gets far enough to the left, so  
> it doesn't trip the "the carriage has returned" lever.  I don't know  
> if it's a lubrication issue or if the CR spring is worn out.  I'm  
> pretty sure it's not the dash pot, as it doesn't get quite that far.

My first thought was the dashpot adjustment, but you say 'it doesn't get 
that far'. I assume by this you mean you've stepped the carriage over far 
enough for the piston to be entirely out of the dashpot cylinder, and 
when it gets a CR, the carriage returns, but not far enough for the 
piston to enter the cylinder.

To me this sounds like gummy lubricants. I wouldn't run a second-hand 
ASR33 (or any other piece of mechanical equipment, actually) without 
going over all the lubrication points. Actually, I'd strip it down, clean 
off the old oil and grease and put it back together again (this doesn't 
take that long if  you have the manuals -- I did my first one while still 
at school (so I was working evenings and weekends), I didn't have the 
manuals, and I was learning as I went, and it only took a couple of 
weeks). 

IIRC when it gets a crriage return, it lifts the pawls from the carriage 
feed ratchet wheel at the front left side of the typing unit. At this 
point the carriage is free to return (pullled by the spring), the pawls 
only re-engage when it gets the next character. You should check this is 
the case (if the pawls are not held off the ratchet wheel, then obviously 
the carriage will be stopped). In the state where thhe pawls are lifted, 
the carriage should move freely, you can move it by hand to see if it 
seems to be sticking.

-tony