Issue with TCB rebooting with certain actions

[Jib]

So I’m back.

I just put the tank back together after having it apart for a while, and upon first power on the TCB froze up. Before it had only done this when I turned the model off and then back on again within the span of a few seconds. Now, even though the model was disconnected, it is doing this when it was first powered on.

The lights (headlights, machine gun lights, break lights) come on and stay on, (as opposed to blinking rapidly) and the red LED on the TCB stays solid red. If I press the reset button then the TCB will boot up properly. The issue is (1) I can’t reach the reset button when the model is fully assembled and (2) the ESC that controls turret rotation and elevation has its own boot up process, and if the TCB doesn’t boot up properly, then it won’t boot up properly, and even if I reset the TCB, I will also have to reset the initialization process for that ESC.

The only thing I changed from before was that I added a audio isolator to the 12v line that sits between the DasMikro and the speaker amp.

Any suggestions? I might try to do a factory reset on it tomorrow, I have all of my setting saved, so I can just reload them afterwards.

[LukeZ]

Well we're still not entirely certain what the cause of this behavior is, which makes it difficult to know where to look for the solution. I suppose the best theory at present is that power is not consistent somehow on boot, possibly your battery is faltering momentarily when all the devices are turned on, and this is confusing the TCB.

One thing you could try that at any rate would at least confirm or deny this hypothesis, is to use a separate battery for the TCB, like a dedicated 2S lipo. This would require you to install a second on/off switch which means you'd have to flip two switches to turn on the model, so that's kind of a pain, but if it eliminated the TCB hangups, that would at least be useful information.

This second battery will need to share a ground with the main vehicle battery (this connection should come before the on/off switches, ie, between the batteries themselves). But you'll need to be careful there is no positive connection between them, otherwise your 40v battery (or 24v converter, or whatever), will try to charge you small lipo, with bad results.

This lipo would power the TCB, and as I understand it, the TCB is also providing 5 volts to your receiver and the DasMikro. That will be fine, those are low current devices. As for the connection between the TCB and your speed controllers, those are only ground and signal, so no current required there, which is good. Lights are negligible. But are you driving any heavy duty servos or other high current devices directly from the TCB? If so that could also be a part of your problem, if they are pulling more than the onboard 5v regulator of the TCB can provide.

[Jib]

So, uh, it just decided to work again today. Maybe the threat of me getting out my computer to wipe the TCB got it to work?

Start up is a little bit different now though, instead of immediately blinking and stopping, now the lights turn on and hang for a second or two, then rapidly blink and everything is initialized properly.

I’ll take what I can get here though. If I have significant problems again I will give the second battery a shot though.

There shouldn’t be any heavy lifting by the TCB. Traverse and elevation are controlled by an ESC with no positive connection. The TCB doesn’t provide power directly to the recoil servo, it does provide power to the drive ESC, but it’s just 5v. Then you’ve got all the connections to the DasMikro. The headlights are stepped up to 12v, but the rest of the lights are 5v. You’ve got the two I/O ports that are just 5v. The smoker powers a 12v air pump, but that is off on start up. Nothing in flash or the built in ESCs. Airsoft powers the 12v automotive relay, but not on start up.

[Jib]

I’m back from the dead with some updates. I’ve got the TCB power separate from the drive and traverse motors.

However, sometimes (but not always) when I turn the front headlights on, the TCB will reset. This happens even when the tank is sitting still and none of the peripherals are turned on. When the TCB initiates the headlights blink normally, but sometimes something about switching them on after that causes the board to brown out. If I press the reset button, then the board resets and the problem is fixed.


The board is powered by a 3s 1300 mAh LiPo that feeds other peripherals such as

2 heaters
2nd reciever not connected to the TCB via a 5v BEC
5 FPV cameras
A video transmitter

None of these things are on when the board browns out/resets when flipping on the headlights.

Any ideas?

[Jofaur86]

Hello, not being a specialist, I'll still offer my humble contribution! Can you visually access the printed circuit board and components? If so, have you noticed anything unusual? Oxidation of a solder joint (from prolonged storage?) or of the PCB itself? Have you tried disconnecting all the peripherals one by one? Are the battery voltage and capacity OK? Maybe my reasoning is silly? But anyway

[Jib]

I did forget to mention I have a 2A 5v->12v booster to convert the voltage because I have LEDs that are 9v-12v.

https://a.co/d/ejJgTST

Battery voltage was a storage charge, so like 11.5v

Before when everything was on one circuit, the card would reset/brown out reliably when I pushed the tank to go really fast.

Now that the TCB and peripherals are on a circuit separate from the drive, traverse, and elevation motors, I thought it would be good. However, the first time I started the tank up after switching to two circuits, it did it again when I turned the headlights on as the engine start up sound was playing.

But then I repeated the issue when the engine was off and the tank was sitting still. But then other times under what appeared to be the same conditions turning on the headlights didn’t cause the board to reset. So it seems semi-random to me right now.

I’m out of town currently, but I will visually inspect the board and maybe take a video of what happens when I get back. I spent some time carving out the plate underneath the blast panels in the turret, so now I am able to easily access most of of the important electronics in the turret.

[Jofaur86]

Okay, I was thinking, after reading your reply, that some modules have different power supplies. Could there be a problem with the ground connections (the negative terminal of each circuit)? But be careful not to fry anything by testing! Is your battery charged for storage? Do you have the correct capacity (amps)? I know all this might seem strange, but sometimes using many electronic modules with different voltages can cause problems.

[LukeZ]

Hi Jib, these intermittent problems are the most difficult to solve precisely because they do not occur every time and therefore it renders the job of eliminating those things which might be the problem until we arrive at the only thing left, which must be the problem.

I do suspect that in the end you are still drawing more current than some component can provide, and this is causing the brown out. Know that any step up voltage converter works by converting current to voltage. If you want to go from 5 volts to 9 or 12, the transformation is made by drawing more current. I am just making up numbers, but imagine for example that your 9 volt LED draws 1 amp (I'm sure it doesn't, but this is just an example), well that 1 amp is what it draws at 9 volts. If you want to power it from 5 volts with a step up converter, it might have to draw 2 amps from the 5 volt source to get 1 amp at 9 volts.

Your 1300 mAh may be having problems sourcing this much current, along with whatever else it is required to power at the same time (TCB, receiver, etc...)

If you still have one of the general purpose A/B outputs available (I can't remember, you may already be using them for something else), you could move the headlight functionality to one of those, which power a 5 volt relay, and the 5 volt relay would provide the 9 or 12 volts directly to the LED. This would eliminate the step up converter.

If that is not possible, you should try using a battery with a greater capacity than 1300mAh, and especially, a battery with a high "C" rating, meaning it can source a larger peak current.

[Jib]

I have some 3s 5200 mah batteries I use for my 1/16 I think I could fit in there, I might give that a try when I get home. Thanks for the helpful example. I still have so much to learn on the electronics side of things.

[Herr Dr. Professor]

Some years ago I got a "Variable DC Power Supply" online. There are scads of them. You can carefully and incrementally set the voltage and amperage to see just how much draw is needed to get whole TCB, etc. starting and functioning correctly. From there you can determine what power source you need.

But before you tank, unh, take, my suggestion, Jib, let's see if others approve.