Help needed from the electronics gurus

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Hey folks, my friend has a pretty nice slot car track that me and some friend race on once a week, but the last couple of months, we've been having some some issues.

The basic set up is as follows:

4 lanes, each measuring about 96', all powered by a common power source running at about 12 or 13vdc . They run with custom software in conjunction with a chip in each car to control the motor and (I think) an RFID chip that allows us to change lanes in multiple places, keep track of us at multiple points along the way, and know when the car is on the track or off so the computer can call yellow flags if you de-slot. There is more, but lets start with that. There is 2 way comms via some dongles to facilitate all this.

The issue we're having is that some of the cars will lose comms with the computer which results in the car going along un-commanded at a slow, but steady pace for a certain amount of time and the computer thinking that the car has de-slotted and calling of a yellow flag. This quite disruptive to say the least. The owner thinks that it might be old and "noisy" motors causing interference. He has tried adding capacitors to the cars on both sides of their power wires to clean up the noise and is also in the process of upgrading the power strips on either side of the slot. (it used to be a steel wire with copper tape over that because they used to race with magnets, but that got boring so he removed them and now we race without them to keep things "more realistic") We are using tinned, braided copper wire and that has improved things quite a bit. The problems do tend to center around the bit of track that is still copper tape, but there is one braided section that will cause them to do it too. Due to time constraints (he doesn't like missing race night due to the track being down) the braid is not continuous. Most stretches are about 12-15'. They are connected under the track though.

The most recent car that he has worked on did seem to respond well to adding caps to act as noise filters, but still goes constant throttle and causes yellow flags on occasion. We are also suspicious that the chips may be losing power (or it drops just enough to reset them) and that's why the computer thinks the car is off. I suggested that we crank up the power to like 16v to try and effect some change (good or bad) and he could just change the throttle curve so we can still drive the car with plenty of control. Has anyone seen anything like this before? Do any of you guys have any ideas? Would adding caps to the main power supply help? Is it possible for the chips to have degraded enough to cause these random issues? One thing that I'm going to do this week is bring my lab scope over and see what there is for noise on the track, is there something else that I can look for while I'm there?

I'm sure that I've left out something, but thanks for any input that you're able to give!
 
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The issue we're having is that some of the cars will lose comms with the computer which results in the car going along un-commanded at a slow, but steady pace for a certain amount of time and the computer thinking that the car has de-slotted and calling of a yellow flag.
Do all cars do this intermittently? Or is it always the same cars intermittently while others never do it?

The most recent car that he has worked on did seem to respond well to adding caps to act as noise filters, but still goes constant throttle and causes yellow flags on occasion. We are also suspicious that the chips may be losing power (or it drops just enough to reset them) and that's why the computer thinks the car is off. I suggested that we crank up the power to like 16v to try and effect some change (good or bad) and he could just change the throttle curve so we can still drive the car with plenty of control.
Going back to the first question, if all, could be power supply or track related. If some cars never do this, find what is common to those and their differences to the ones that do this intermittently.

A cleaner such as DeOxit Gold may help. This stuff is effective at cleaning electrical contacts when nothing else works. I've used it for many years, but the one place it really shines is the lens contacts on Nikon DSLRs. Seen too often where others said "I've cleaned the contacts 100 times", then the DeOxit Gold works. Check the expiration date at purchase. A 5oz can will last you for many, many years.

Added: Do not overuse. I like to use the term "a light spritz", but that's almost too much. You could almost spray some in the air and move the contacts through it and get the perfect amount.

This is the product Panasonic recommended to use on the connection between their plasma panels and driver boards, back when Panasonic was making plasma tvs.
 
Do all cars do this intermittently? Or is it always the same cars intermittently while others never do it?


Going back to the first question, if all, could be power supply or track related. If some cars never do this, find what is common to those and their differences to the ones that do this intermittently.

A cleaner such as DeOxit Gold may help. This stuff is effective at cleaning electrical contacts when nothing else works. I've used it for many years, but the one place it really shines is the lens contacts on Nikon DSLRs. Seen too often where others said "I've cleaned the contacts 100 times", then the DeOxit Gold works. Check the expiration date at purchase. A 5oz can will last you for many, many years.

Added: Do not overuse. I like to use the term "a light spritz", but that's almost too much. You could almost spray some in the air and move the contacts through it and get the perfect amount.

This is the product Panasonic recommended to use on the connection between their plasma panels and driver boards, back when Panasonic was making plasma tvs.
No, it's only a certain few cars.. to be honest I'm not certain if conductivity plays a roll, but I don't think it does? I seem to recall that the problem persists even after changing the braids on the problem car.. I'll bring some Deoxit though and see if that makes any difference.
 
No, it's only a certain few cars.. to be honest I'm not certain if conductivity plays a roll, but I don't think it does? I seem to recall that the problem persists even after changing the braids on the problem car.. I'll bring some Deoxit though and see if that makes any difference.
If always the same cars, it will be a matter of determining what is different about them from the others (realizing I'm preaching to the choir).

You'll never regret having a can of DeOxit Gold around the house. You may not need it for a year, and then you need it. Also does a good job on trailer wiring... anything having an electrical connection. :rolleyes:
 
Is your track really @96'?

I'm not into slot cars but I do model trains. When we build a layout we add power to the track at multiple areas around the track. This, and proper feed wire size, is important to ensure there is enough current for the load. Stranded wire will carry more current than solid wire. This, of course, is if your system uses DC current.

Edit: More information is needed. Are your cars using DC motors? Are the cars controlled by an RF source or do the commands ride along with the power supplied to run the cars?

Model trains run on DC power and control commands are on the DC power as a digital square wave. Our system is called DCC (Digital Command and Control).
 
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This has mostly been said in the posts above but.....

Your lab scope might help reveal noise issues. Since it's only certain cars I wouldn't make any big changes to the track setup just yet.
You said it was mostly along the sections with the old copper tape. Use a VOM and check the resistance along sections with no problems (or less problems) against the resistance of sections where there do seem to be issues. If there is increased resistance there will be less current available there (but it would actually affect the entire track). Carefully check where the connections are between sections (of course). Voltage tests could also be revealing.

A TinySA Frequency Spectrum Analyzer might be a good investment if electrical noise is a concern. It's small and yet powerful and might be easier to use for this than a regular lab scope.
https://a.co/d/c8qBlMB

You could also test to see how much current the problematic cars are drawing vs those that have no issues. The TinySA will easily show the electrical noise and it's spectrum vs the cars with no issues.

As your master power supply ages, it may also have a decrease in the current it can supply. Load test it then calculate the total load on it (track + cars + communications bus etc)

Just my 2 cents.
 
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$58 for spectrum analyzer??? Those used to only be found in expensive labs! D@mn, I'm old!

You're not alone. I just found out about them recently. Bought one. Love it!
I use it mainly for analyzing vehicle fob and modules frequencies. (No, I don't steal cars):ROFLMAO:
But it has 1000's of potential uses.
 
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