D-Line Scoreboards Behaving Badly

You did not mention where you were writing from so we don't know the circumstances.

I gather that the displays are located at the base of the hill and the timer/pc is at the top.

It may be that the serial signal is just not strong enough to carry all of the data to the bottom. The resistance on the pair is not listed but it may be too high. The NASTAR software is sending out a fairly long string of data that the displays are trying to receive, parse, and display. The test pattern is a much shorter "burst" of data than "timing" so that is why it appears ok and then becomes corrupted.

Connecting the displays locally to the pc/adapter with a short cable should isolate this.

Solutions for this include:

1) Swapping another wire pair. Try your green course finish line for data and data line for finish.

2) Getting a serial booster amplifer

3) Transmitting the data wirelessly

4) Running another cable down the fence or through the woods

Thanks Frank,

You're correct, I'm running the laptop from the top of the course and sending the signal down our main line to the boards at the bottom. I'll check the resistance today and see if that may be the issue.

We've been using the same setup for years and have never had this problem, it started last week and I can't explain why things have changed. I did bring the laptop down to the finish and connect directly to the scoreboards, and everything ran fine, confirming that it is the line and not the boards.

As for your tips:
1) I tried swapping pairs and got the same problem.
2) I can only find 25-pin serial port boosters, do they make them for 9-pin serial ports?
3) Wireless may be a short term solution, but I'd like to get the hard line back up and running.
4) Running another wire is difficult for our setup, due to the length and the runs that cross the course.

Thanks again for your help!

Try B & B Electronics. They have a wide array of serial devices that might fit the bill.

http://www.bb-elec.com

1) Meter the voltage going to the D-Lines.

2) Meter the voltage going to the laptop.

3) Try running the laptop on battery only, see if it affects the problem.

4) Try running the D-Lines on a UPS which is not plugged in to AC voltage, see if that affects the problem.

I think you see what I'm getting at here. The problem may not be bad pairs, at least not directly. You may be sending voltage up and down the hill on your pairs due to a ground mismatch, or simply poor grounding. You don't mention where your race hill is, but this is especially common in The Rockies, where the soil is chock-a-block with ferrous metals.

A voltage regulator may do the trick. In the meantime, if either the laptop or the D-Lines burst into flames, you've found the problem.

Thanks everyone for your help. The temperature rose above 0 yesterday and the boards started to work fine again. (You can imagine my frustration and surprise when they worked again, "magically") The temperature dropped this afternoon and the boards started to fail again.

I believe I'm having a voltage/temperature issue with the USB to serial port adapter and I've ordered a serial line booster, as recommended by Allan. I'll post an update when I can confirm if this helps, for future reference.

Thanks again to everyone!

James,

Yes, I'm in Jackson, WY. I'm really hoping that the serial port signal booster does the trick and I don't need to troubleshoot any more. The fact that the boards fired back up when the weather warmed seems to be an indication that the voltage was connected coming out of the computer, hopefully at the USB serial port adapter. My fingers are crossed!