Re: Daisy Wheel Printer repairs

Both the black and red wires have capacitors on them, which connect to the chassis ground. I'm guessing these are for noise suppression... the Apple branded printer had tons of extra ground straps running all over the place, and some extra shielding the Qume branded printer didn't have.

Perhaps what is making me doubt my pictures is that the Qume branded printer had the motor connected through the microswitch. Perhaps this is why I didn't take detailed photos of the Apple branded printer... the black and red wires hook to the black and red terminals on the motor and the 2 white wires go to the switch.

To get at the black terminal on the motor the chassis has to be removed. But I should be able to do a test without bolting the whole machine back together.

Another difference between the Qume and Apple branded printers: The control / amp board for the sensor on the motor is attached to the motor on the Qume printer, on the Apple printer it is on a socket on the logic board. The socket header is the same on both though, I'm guessing this was just a manufacturing update that happened between 1983 and 1993.

Thanks for the suggestion James, I think it helped jog my memory.

-J

On Tuesday, July 7, 2015 at 10:48:15 PM UTC-4, James MacPhail wrote:
>
>
> >Here's some links to high res pictures I took. I can't tell where
> >the red wire should be going... in one photo it looks like it goes
> >right to the motor, in another it's plugged into the switch. Perhaps
> >I misconnected it somewhere along the way?
>
> Hard to tell for sure from the two photos, but:
>
> 1) It looks like the switch is a simple/common SPDT "microswitch"
> (brand). If so, and depending on its function, it is highly unlikely
> that more than two of its terminals would be connected. ie. the
> controller would want to know when the switch changed state, and it
> only needs two wires to do that.
>
> 2) It looks like the red wire also has a capacitor wired to it. That
> would be for interference suppression, and normally isn't required
> for a switch that operates intermittently, but quite possibly be
> needed for a stepping motor.
>
> 3) It looks like the motor doesn't have any other wires connected to it...
>
> So I vote for "should be connected to the motor", but you could try
> powering it up with the wire disconnected and see if you get any
> information from the behaviour.
>
> Good luck!
>

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