GPUSB and EQ5 with ST4 mod not working

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rickchavo
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GPUSB and EQ5 with ST4 mod not working

Post by rickchavo » Tue Apr 17, 2012 3:48 pm

Hi, I'm Ricardo, and a few months ago I purchased a GPUSB box. Just recently was I able to modify my EQ5 dual axis control to incorporate a ST4 port, but it didn´t work. That is, I connect the GPUSB box to the PC and it gets detected; I run GPUSBCheck and everything is OK: I can change the LED's colors, and press the buttons.

However, when I connect the GPUSB box with the hand controller via the ST4 port, the handpad central LED, which is green when powered up and turns red when a button is depressed, just turns red all the time. If I get close to the motors, I can hear them moving constantly. It looks like some buttons are depressed continuously.

Noticeably, this happens EVEN if I disconnect the GPUSB box from the PC, and keep the ST4 cable attached. As soon as I reconnect the ST4 cable, the handpad LED goes red and the motors start moving, no matter if the GPUSB box is connected or not. I disconnect the ST4 cable, the led goes green and the motors stop. I re-checked the cabling and soldering again and again, and it seems OK.

Any ideas? I saw on (http://thx8411.over-blog.com/pages/Add_ ... 58969.html) a similar modification, with different cabling, but I'm afraid of burning up the handpad in case it's wrong. On the other side, I saw people on this forum successfully modifying similar handpads, so I don't understand what can be going wrong with mine.

PLEASE! any help is REALLY appreciated!
Yours,

Ricardo.

dpanderson
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Re: GPUSB and EQ5 with ST4 mod not working

Post by dpanderson » Tue Apr 17, 2012 6:35 pm

Let me be sure I understand your situation.

1) With nothing plugged into the ST4 port you added to your EQ5, the motors do not run.

2) As soon as you plug in the cable only (no GPUSB attached), the motor starts to run.

If this is correct, then it sounds like your cable is bad, maybe there are two wires shorted together.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

rickchavo
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Re: GPUSB and EQ5 with ST4 mod not working

Post by rickchavo » Tue Apr 17, 2012 10:02 pm

Hi Doug, thanks for answering so promptly!

1) This correct; with nothing plugged into the ST4 port, motors don't run (they run only when handpad buttons are pressed, as it's supposed to) and LED stays green.
2) If I only connect the ST4 cable to the handpad AND NOT to the GPUSB box, the situation is similar as before (motors don't run).
3) If I then connect the ST4 cable to the GPUSB, both motors start to run (and handpad LED becomes red), NO MATTER whether the GPUSB box is connected (via USB) to the PC or not.

I checked the ST4 cable with a tester and there's no short-circuit. I purchased the cable from Shoestring.

Please let me know your thoughts. Best regards,

Ricardo.

dpanderson
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Re: GPUSB and EQ5 with ST4 mod not working

Post by dpanderson » Wed Apr 18, 2012 5:27 pm

OK, now I understand better. It sounds like the pinout order on your connector is wrong. Here is our instructions for modifying this handcontroller:
http://store.shoestringastronomy.com/eq_mod.pdf

Please read through this, especially page 8, and verify that your pinout is the same as shown there.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

rickchavo
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Re: GPUSB and EQ5 with ST4 mod not working

Post by rickchavo » Wed Apr 18, 2012 8:51 pm

.....hmmm..... I bought a female RJ-11 connector to modify my handpad, and took for granted the colored wires were in the right position, .....BUT..... now I see that they are colored the same way, but in reverse order.

Thanks for your support! I will re-solder the wires again, and let you know.

dasPaul
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Re: GPUSB and EQ5 with ST4 mod not working

Post by dasPaul » Tue Jul 22, 2014 11:12 am

I've encountered the exact same problem. Connecting handbox to GPUSB turns handbox led red and no movement is possible. So I reviewed my wiring and found out I did the opposite (the wrong way round) of how it has to be because I used a picture that did not describe the wiring conclusive and where PIN1 was locatet. So I made a picture, maybe this helps someone getting in same trouble:

Image

after rewiring everything works fine and I am happy that I did not destroy the gpusb-box.

greets
paul

dpanderson
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Re: GPUSB and EQ5 with ST4 mod not working

Post by dpanderson » Tue Jul 22, 2014 6:12 pm

Thanks for posting this Paul. There is no standard pinout numbering scheme for the RJ12 connector. We follow what appears to be the most commonly used scheme which is shown in this document:
http://store.shoestringastronomy.com/gu ... cables.pdf
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

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