Shoestring Astronomy Support

Can anyone help me? I'm not very knowlegeable about this stuff.

I have some old equipment - super C8 , beyers mount which I manually guide using a JMI Mototrac V (unit is no longer manufactured...manual controls work perfectly). I'm trying to set up autoguiding. The Mototrac V has a CCD input (ST4 compatable). I purchased a GPUSB relay, ST4 compatable cable and downloaded Guidedog software. Guidedog is talking with the relay ( using Guidedog checker) but the relay does not talk with the Mototrac V. I'm pretty sure that the RJ12 cable wiring is correct.

Can anyone help me diagnose the problem? I'm assuming that I don't need any software interface between Guidedog and the relay. Is that a correct assumption?

Thanks,

Jim

Jim,

I don't recall the details of your order, did you purchase the RJ-12 cable from Shoestring Astronomy?

Try downloading, installing and running GPUSBCheck from:
http://www.store.shoestringastronomy.com/downloads.htm

The instructions for what to do with GPUSBCheck are in the GPUSB User Manual, also available on the download page linked above.

Also, remember that the movement of the scope will be extremely small and almost unnoticable. Usually it is best to look for movement of the motor, or to listen for the sound of the motor running.

If you have no success with the above, let me know.

Yes, I purchase the RJ12 from Shoestring. Also, I'm preety sure I'm not getting any response from the Mototrac V - the declination motor is easy to hear if there is any movement. I'm also pretty sure the wiring is correct.

Jim

If you have a voltmeter and know how to use it, I will describe a set of tests we can use to try and debug this. Also, if you could point me to any technical documentation Mototrac-V, preferably on the Internet, I might be able to make some sense of this.

Doug - Thanks for trying to help. I do have a voltmeter and have a limited understanding in how to use it. The following is a link to the Mototrac V Manual: http://www.jimsmobile.com/index.htm

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OK, based upon the Mototrac V manual on the JMI website and the fact that you have an "official" Shoestring RJ-12 cable, this should work. So let's try some voltmeter tests and see if we can figure out what is wrong.

Where the RJ-12 jack bumps up out of the GPUSB, there are exposed metal contacts that make a great place to probe the voltage on the pins. Have everything cabled up to your mount, Mototrac powered up, and GPUSBCheck running on your computer. Set the voltmeter to voltage mode, with a range suitable for 10V DC. Using the pin numbering scheme shown in:
http://www.store.shoestringastronomy.co ... cables.pdf
put the negative probe on pin 2 for all the measurements listed below.

1) Probe the voltage on pin 3 with the positive probe, it should be a high voltage like 5V, but possibly some other value.

2) Repeat for pins 4, 5, and 6. They should all be a high voltage.

3) On GPUSBCheck, click on one of the direction buttons. Now go back and probe pins 3, 4, 5, and 6. One of them should have dropped to a low voltage near 0V, but possibly up to 0.4V.

4) Unclick the first direction button on GPUSBCheck and then click a different direction button. Now a different pin should go low. Repeat for all direction buttons.

Let me know what these measurements reveal.

P.S. I will be leaving on vacation on Sunday morning for two weeks. I won't be able to respond until after I return.

Sorry for the delay in my response. I also was on vacation. I checked the initial voltage according to your instructions. I'm only showing 2 or 3 hundreds of a volt. I'm sure I'm using voltmeter correctly. There's no change when any of the direction buttons are activated.

Jim

When I mentioned in last email "direction button, I was refering to the CPUSB check program.

Jim

Were the voltage readings you measured positive or negative (using pin 2 to the negative lead of your voltmeter)? It is possible that the Mototrac V is an "active high" device. If so, we can try the GPUSB-AH to see if that solves the problem.

I will email the folks at JMI and see if they can give me more details on the guide port.