Digital BW, The Print

I agree regarding troubleshooting the stepper -- not much fun, but 
from John's last post it does sound like there is some life in it.

The stepper motor is driven by an LB1845 (a pair in the 9000). This 
is a PWM current control type device that has internal thermal 
shutdown circuitry -- it's a pretty common and sturdy chip.

There isn't any direct feedback loop in that section of the circuit 
(but the ASIC may well be sensing the state of the 42V supply line). 
The the main board just outputs it's control to the stepper on a four 
pin cable, CN24 -- that's the connector that was giving John grief 
before, so it's definitely suspect... 

Richard 

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "dfaprinting" 
<dfaprinting@y...> wrote:
> --- In 
DigitalBlackandWhiteThePrint@yahoogroups.com, "richard_h95050" 
> <richardh@j...> wrote:
> > --- In 
DigitalBlackandWhiteThePrint@yahoogroups.com, "dfaprinting" 
> > <dfaprinting@y...> wrote:
> > 
> > 
> > We're thinking along the same lines here regarding the pump motor 
> and 
> > trying to save John a lot of work in case it's not the main 
> board ;>)
> > 
> > The motors in the 7000 and 9000 are the same spec-wise, but carry 
> > diffent part numbers. They are both steppers (4 phase 200 cycle 
HB 
> > types) with the same control voltages.
> > 
> > Ciao,
> > 
> > Richard
> > 
> > 
> That stepper isn't going to be much fun to trouble shoot. Too bad 
> they couldn't have just used some kind of simple DC motor with a 
gear 
> head for reduction. Do you know if there is any feedback from the 
> motor that the board needs to tell if it is running?