Problem with GPUSB

Questions about hardware and software obtained directly from Shoestring Astronomy
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John Bunyan
Posts: 2
Joined: Wed Jun 27, 2007 9:52 pm

Problem with GPUSB

Post by John Bunyan » Thu Jun 28, 2007 12:16 am

I have my gpusb connected to the computer, The gpusb software up and running and the green light is on. I tested the output voltage at the gpusb and find that I get no voltage. I used a multimeter tester and put the ground wire on the #2 pin and tested all the other pins and no volts. Is the unit bad or software?? HELP.

John Bunyan
Posts: 2
Joined: Wed Jun 27, 2007 9:52 pm

continued

Post by John Bunyan » Thu Jun 28, 2007 11:53 am

To continue, I plugged in the 6-pin cable to my Orion Atlas mount and while the mount was tracking I tested the voltage at the GPUSB. #6pin was 4v, #5pin>1v, #4 4v, #3>2v I then pushed the +ra, -ra etc on the GPUSBcheck and the mount did not move. Any suggestions besides the cable which I've tested and replaced just for the heck of it..

dpanderson
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Post by dpanderson » Thu Jun 28, 2007 1:16 pm

John,

I don't recall the details of your order, but did you buy the RJ12 cable from us? If not, are you absolutely certain it is wired pin 1 to pin 1 as outlined in this document:
http://www.store.shoestringastronomy.co ... cables.pdf
Most RJ12 cables in stores are wired pin 1 to pin 6 and thus will not work properly with the GPUSB.

Regarding your testing when the GPUSB is not connected to anything:
The GPUSB outputs do not put out voltage levels. There are really more like SPST swtiches from pin 2 to pins 3, 4, 5, and 6. However, they are actually open-collector transistor outputs, so the best way to check them when the GPUSB is not connected to anything is by using the "diode check" function that is found on many multimeters. When the "switches" are open, the meter should read off-scale. When a "switch" is closed, the meter should read 0.3V or less.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

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