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Meru
03-04-2012, 09:34 AM
Hey guys,

I recently bought a GPUSB from a user here, whom I won't mention. I didn't get the chance to use it for about 1.5 months, and when I finally used it - Suprise, it doesn't work :( It connects to GPUSB/PHD fine, I can control the LED and run other diagnostics.

However, the issue is that the GPUSB will not guide in RA(+) and Dec(-). The other two directions work fine, infact I can manually guide in that direction in PHD as well. The ST-4 port on my mount is perfectly fine, works just fine with my SSAG. I checked the outputs on the GPUSB and confirmed that it is a GPUSB-related issue.

I tried contacting the member, suggesting that the product shouldn't just stop working if I dont use it for 1.5 months! He claimed it worked fine with him, but he can't be of much help and hasn't got the time to check it and isn't taking it back.... I really dont mean to complain but now i'll have to think twice about make purchases online :mad2:

So anyways my question is this - Has anyone else encountered this problem before? I've contacted shoestring to see if they can do anything, but in the mean time thought someone here might be able to shed some lights. Any help would be great, thanks alot for reading :)

Meru
11-04-2012, 12:39 PM
Just an update if anyone has the same issue next time, turns out it was a faulty IC on the board. There's two ICs on the board; a PIC which interfaces with the USB and sends signals, and an Optocoupler (TLP627-4) which 're-sends' the signal.

The Optocoupler was faulty so replaced it, works fine now. It also suggests that it must have been faulty when bought... but hey, atleast its been fixed with a $3 part :)

GeoffW1
11-04-2012, 07:46 PM
Hi,

You did well to diagnose it. Experience noted

Cheers