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Encoder

I ripped apart an HP printer and on the back of the carraige that the
moved the print heads around was an encoder and a 400 LPI encoder
strip. The encoder is labeled H9721P. I can not find a datasheet for
it, but there are only 4 pins. I'm guessing one is power, another is
ground, then two sensor outputs. I'm curious if the is any way to
determine what pins are what?

http://rowell.info/~richard/h9721P-front.jpg
http://rowell.info/~richard/h9721P-back.jpg

It looks like C2 connects pin 2 to pin 4 (if you count the pins from
left to right as viewed on the "front" image)

TIA!
 
N

Nutz

Jan 1, 1970
0
I ripped apart an HP printer and on the back of the carraige that the
moved the print heads around was an encoder and a 400 LPI encoder
strip. The encoder is labeled H9721P. I can not find a datasheet for
it, but there are only 4 pins. I'm guessing one is power, another is
ground, then two sensor outputs. I'm curious if the is any way to
determine what pins are what?

http://rowell.info/~richard/h9721P-front.jpg
http://rowell.info/~richard/h9721P-back.jpg

It looks like C2 connects pin 2 to pin 4 (if you count the pins from
left to right as viewed on the "front" image)

TIA!


By convention pin 1 often has a square pad. Is your pin 1 really pin 1?
 
I ripped apart an HP printer and on the back of the carraige that the
moved the print heads around was an encoder and a 400 LPI encoder
strip. The encoder is labeled H9721P. I can not find a datasheet for
it, but there are only 4 pins. I'm guessing one is power, another is
ground, then two sensor outputs. I'm curious if the is any way to
determine what pins are what?

http://rowell.info/~richard/h9721P-front.jpghttp://rowell.info/~richard/h9721P-back.jpg

It looks like C2 connects pin 2 to pin 4 (if you count the pins from
left to right as viewed on the "front" image)

TIA!

Well, the capacitor that goes to what you think is pin 2 would suggest
it's the power pin. The other side of the cap would be ground, now you
can beep it out.
Or just apply power to the board and measure it. Or find a
conventional IC on the board and measure it.
So many ways.
 
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