GPUSB not guiding in RA(+) and Dec(-)

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Meru
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GPUSB not guiding in RA(+) and Dec(-)

Post by Meru » Thu Apr 05, 2012 2:03 am

Hello,

I recently bought a GPUSB from a classifieds section, and it doesn't seem to quite work. The issue is that the GPUSB will not guide in RA(+) and Dec(-), though it connects to GPUSB/PHD fine, I can control the LED and guide in the other two directions. It isn't a mount-related issue either since the ST-4 port on my mount is perfectly fine with my SSAG.

I've also checked the outputs on the GPUSB and confirmed that it is a GPUSB-related issue. I couldn't find any broken tracks on the PCB so am stumped. Has anyone else encountered this problem before? Perhaps the IC needs a re-flash?
Any help would be great, I really am keen on using the GPUSB :)

Regards,

Meru

dpanderson
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Re: GPUSB not guiding in RA(+) and Dec(-)

Post by dpanderson » Thu Apr 05, 2012 5:32 pm

The most likely cause is that the optocoupler (the tan colored component with 16 legs) that drives the outputs is damaged. This is a TLP627-4.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

Meru
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Re: GPUSB not guiding in RA(+) and Dec(-)

Post by Meru » Fri Apr 06, 2012 2:35 am

Hi Doug,

Thank for the prompt response. I'll be ordering the IC this week so hopefully should resolve it, I'll post the outcome

Meru
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Joined: Mon Apr 02, 2012 6:12 pm
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Re: GPUSB not guiding in RA(+) and Dec(-)

Post by Meru » Tue Apr 10, 2012 9:32 pm

Hi Doug,

While the TLP IC is on the way here, I checked the inputs to the Optocoupler and turns out it is indeed the culprit, since the PIC is sending signals just fine. Thanks for the advice once again :)

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