TI Silent 700 model 733 manual

Tony Duell ard at p850ug1.demon.co.uk
Sun Jun 7 12:34:14 CDT 2009


> > This is a well-known problem on all sorts of devices. Someitmes the 
> > grease will soften with common solvents (propan-2-ol, etc). There's a 
> > green grease used in some camera lans mounts that goes rock hard with age 
> > and nothing wil shift it short of scraping it out....
> 
> yes... I had to clean it out of the raceway of the solonoid as well as
> off the plunger.  It was really like glue.  WD-40 seemed to do a nice
> job cutting it actually.

I hope you cleaned the WD40 off as well. The problem is that the lighter 
solvents evaporate and leave a waxy deposity (the longer chain 
hydrocarbons) behind. Just what you want for its original use of Water 
Displacemnt, but not what you want in a Silent 700.


> 
> > > I also see that the stepper motor that actually turns the platen (or equiv
> > > of) is not making a full increment each time.  Sometimes it advances but
> > > other times it de-advances.  So, something it messed up in the stepper
> > > circuit or the grease in that stepper motor has turned to honey too.
> > 
> > Maybe you've lost the drive to one of hte stepper phases. That can make 
> > them step in thwe wrong direction sometimes.
> 
> That was absolutely it.  It was a fun afternoon tracing out the circuit

Occasionally i make a good guess :-)

> Great stuff.  Cool to see all those TTL parts and not a one of them is
> LS or HCT or anything close.  74XX was it in 1973.

Well, at that time there was also 74Lxx (lower power, slower), 74Hxx 
(higher power, faster) and 74Sxx (fast!). I've come across all those 
families in classic HP hardware of that period.

> 
> Note that I have really good luck with modern thermal FAX paper in these
> units.  Around here it is readily available at office supply stores on

I am not suprised. I use it in my HP thermal printers with no problems. 
My 9866A (full-width thermal printhead, it's a sort of line printer...) 
just works....

I repaired an HP2761G (moving head thermal printer). I went to a 
stationers locally, and all they had was 210mm wide paper, the 2761 
having a 216mm wide chassis. I found if I positioned the roll just right, 
it would work, and the head wouldn't snag on the edge of the paper. So I 
machined a couple of brass disks to put on the paper roll spindle to hold 
it in the right place. Worked fine, and I was happy until I went to 
another branch of the same stationers to find they also had 216mm thermal 
papepr...

> 98 ft rolls.  They have a 1/2" dia core which needs a piece of dowel
> to support it in the 725 (and probably in the 733 too) and it is a much

I am sure I can make up something to hold it...


-tony




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