Transponder issues at recent race
 

I've been running an AMB transponder for about two years now at various tracks with never any problems. I used it in Traxxas Slash's, and 1/8 nitro and electric buggies and truggies. Most recently, I ran it in my relatively new Hyper 9e, and once again had no issues, up until just this weekend at the Gulf Coast RC Challenge at Mike's hobby shop in Porter, Texas.

I had it mounted the way I had always mounted it, using the 9e's nice little platform which suspends the transponder above the servo (Hitec 7955TG). All throughout practice day, it worked fine, calling out my lap times as usual. But during the qualifiers, I started having severe problems. First, during the second qualifier, which was an 8-minute race in which I could average 18 laps, either my transponder or GCR's LCS counted only 7 laps, one of which was 126 seconds and other over 260. The race director said "You had some doubles," which meant it counted twice at one pass over the loop. I don't see how that would explain the ridiculously long lap times, though.

The next day, I had the race director check my transponder again when no one was on the track, by rolling it over the loop at walking pace. I did it twice, and both times he said it counted. But, during the first of the three A mains that I had barely squeezed into, it only counted ONE LAP.

The ESC was an up-to-date Tekin RX8. Spectrum SR3100 receiver. 6.0v going to the Rx. The light on the transponder always glowed bright orange, even under full power and steering, throughout the weekend and does to this day.

I tried mounting the transponder directly to the chassis, rather than two inches higher and through the servo. That didn't help. I also added a capacitor (thanks to Mike Scoll), but that didn't help either.

Could this be my transponder, or the track's LCS, or some other issue? Like I said, I have run this transponder in several cars, most of which were 1/8-scale buggies with 4S power and Mamba Monster systems. Also, for about four months, I ran a Castle BEC to my Rx, at 9.0v. I know that sounds too high, but it worked beautifully, with never a hiccup from the Rx, servo, or transponder. Could that have done damage to my transponder? Sorry for the long read, but I felt that all of that information needed to be stated.

Yep.

Other than that, your question requires an equally long answer, and that is that it really depends on the circuitry within the transponder but if it's designed to work at around the 4.8-6v mark, 9v is between 50 and almost 100% overvolt which could damage something. I'm not sure of the exact design or particulars of a transponder circuit but in function it is a very basic, short range transmitter.

Most IC's (microchips) are designed to work on either 3.3 or 5v (3.3 is much more common but there are chips that work on less - hence 1xAAA mp3 players and the like). Therefore, when supply voltage exceeds this, there is a regulator to keep the input voltage at the correct voltage.. 2.4ghz TX's work this way as their transmission parts also run on 3.3v. The regulator shunts off the excess voltage as heat, and has a very definite amount of power(heat) it can shunt before it goes into the state known in the trade as thermal runaway or in laymans terms "burns out"

When people leave 2.4ghz TX's (particularly those modified with 3s lipo) on for some time, such as forgetting and leaving them on overnight, sometimes the regulator which delivers the 3.3v to the transmission parts of the circuitry can partially burn out, which results in them not being able to supply the current the circuits need, which leaves the TX seemingly still working, but having almost no range.. as little as inches..

It is possible that your 9v running has done this to the regulator on your transponder. When you moved the car past the counter just you and the guy at the track, was the car closer to the counter's pickup than it had been whilst you were lapping? Try moving it past the counter at different distances and speeds.

I think "you had a couple of doubles" was just an excuse to fob you off. If the above test yields no data, try the transponder at another track.

FWIW I was there as well. Pitting with/next to Dan and Mike. My transponder did the same thing as did another guy in the same heat whose didn't count at all. After a little asking around it became apparent that this has been an issue before at this facility. Not sure what the reason is but I don't think it is your transponder Dan.
From what I gathered Dan didn't change anything all weekend. His car went from counting perfectly to only counting sometimes, same as mine and everybody elses that had a problem. I do know that the director rebooted the computer several times during the day. Not sure if this had anything to do with the apparent issue or not. He did tell me via "the red phone" that this happens alot with the E-Buggies.
I think you should try to race at Indy Tuesday night and see what happens. My money says that it works just as good as it did before you left based on the other issues that happened over the weekend.

We also have experenced this same problem at our club track "RCSX" and later discovered that it was the fault of the input power to the faclity that caused the problem, amb systems are very sensitive and will function better if you use a power backup system much like you would use on a computer system this will give the amb a constant power level to run at. after installing one on our system we now have a very accurate lap counting system without glitches:nod::nod::nod:

That was very informative, and I greatly appreciate your input. The thing is, though, my transponder worked fine in my RC8Be (which I sold on this forum a few weeks ago) for a period of about four months, always running 9.0v. And it continued to work fine at all other tracks besides Gulf Coast Raceway before the event. Just the week before, I ran at Indy RC World in Garland, TX, having the transponder mounted above the servo as I stated before, with no issues ever. What Wes (RACETEK) said is also correct- he as well as others were having transponder issues as well. I can't do another test at that track (GCR) because I live three hours away from it.

I just hope I don't have to plunk down $100 for a new one. I will be making a trip to Indy AND Mike's in DFW to test it at both tracks. Talking to Wes here- I can't make it tonight, because I have lots of homework to do this week. Most likely I can make the trip this Sunday, going to Mike's first and then Indy.

This sounds like the most-likely cause. Thank you.

I doubt it was a double count... Most software allows you to put a delay in the system. Say you are turning 20 sec laps... you set the delay to 18... it won't allow another count till after 18 sec. Now if you guys have picked up the pace and start turning 17 sec laps.. yeah.. you're missing laps... every other one lol. (seen this happen)

I work with UPS systems (a good thing to have)... but I doubt thats the problem... Most transfer to slow to pick up momentary glitches from a utility... even then most produce a square wave ac... which isn't the cleanest.

As a race director, its always easy to say "gotta be your TP". But with multible racers having problems... he's gotta check his system. First thing to check is the background noise. If its high (50 or above) hes got a problem. More then likely, its the COAX and/or loop.

FWIW...I raced the Tuesday night program at Indy RC World in Garland, Tx tonight and my car counted every single lap, every single time..

Looks like it was both a degrading transponder due to too much voltage, and GCR's lap-counting system.

I raced the same transponder at Indy RC this past Saturday night, and while it did count every lap, it said my signal was weak in at least one of the qualifiers.

Guess I'll be looking for a new one soon. Which is not as hard of a $100 pill to swallow, now that I realize the new generation units can handle up to 16v.