TOPIC:

I'm tyring to work out what is wrong with my 2019 Grasshopper. I have a Tamiya TBLE-02S ESC and a Absima SR2S control system.

On power up the beeping motor, and flashing LED on the ESC suggests the receiver and transmitter have stopped linking up.  I've also noticed that there is no red LED on the receiver  in normal operation, or when I try to rebind them. However I'm also not seeing this lit LED on my new receiver combined with new ESC or any combination of the two. (I've changed both for identical replacements.)

Could someone tell me what voltage I should be measuring on the Vcc connection to the receiver. One ESC outputs 1V and the second one outputs 2V. From the receiver spec this looks to be too low.

Thanks.

TBH I CBA to go & measure it right now but I'd expect 4.8 to 6v between the red & black wires on the 3-pin plug, with a functional, charged battery connected & the ESC switched on. 

Has your setup ever worked, or is this a new problem? 

Thanks.

My car was running ok for about 9 months, but then started to behave irratically - juddery speed. Then it stopped working altogether. Now when I power it up I get a continual beeping, and continual flashing LED on the ESC. The manual says this happens if the receiver is turned on without the transmitter.

I thought the receiver was the likely fault so bought a replacement. I went through the binding process, (but I don't think I checked for the red power LED on the receiver). No change in the symptoms. So got a new ESC as well. Still the same symtoms.

So now I've been looking at things more closely and can see that there is no red LED on either of my receivers, connected to either of the ESC. Vcc output on the original ESC is 1V and 2V on the new ESC. The Absima manual suggests it needs 4.8 - 6.6V.

I'm now wondering if my motor is the root cause, and it's damaged my original ESC and the replacement. (When I powered up the replacement ESC I had it connected to the motor.) I've measured the resistance of the motor to be about 4 ohms. Any idea what it should be? It's the standard 280 motor.
 

Couldn’t find my electronic MM, the megger wouldn’t be the right tool & my cheap analogue MM isn’t really scaled for low impedances – but I was getting around 0.3 ohms on the 10X scale. Not conclusive, but we’re not orders of magnitude out. 

Experience makes me question whether a wee kit motor could cause ESC issues anyway, even with the tightest gearbox, run for an unsympathetically long time on a high drag surface I’d only expect to see the ESC “thermal” (thermal overload protection/sulk) for 10 to 30 minutes before coming back to life.  A qualitative test (single D cell across the motor connectors is usually informative – if everything spins ok, then the motor & gearbox are fine. 

Any chance the ESC has got wet? Tamiya units aren’t in the least bit water resistant & are very prone to misbehaving with even the smallest amount of contaminants … I’ve rescued many by swooshing out with DI water (even tap water) & drying carefully. I’d want to exclude the RX as the problem, cheapest/best way might be a 4xAA holder with a suitable JST connector. You can always use it to power a servo tester  

Battery? I’d have to look at the ESC specs, but while 2S Lipo (nominal 7.4v) or 4N to 7N (four cell/4.8v to 7 cell/8.4v Nicad/NiMH) are fine, anything more than that is likely to kill it. Even if it’s correct, they have a limited lifespan, especially cheap (though not necessarily inexpensive) packs & those in “deal” packages. I’ve always got on well with moderate capacity Vapextech packs if you’re looking for a replacement. 

“Tamiya” 7.2v battery connectors are notoriously unreliable in an RC application, resulting in poor contact and/or massive resistance, I think everyone upgrades at some point. Most seem to get in a masturbatory frenzy about “T” (aka “Deans” connectors), I like XT60 types for Lipo & modular Anderson powerpoles for Ni-Cd &  NiMH, there are lots of possibilities. 

I’ve just tested a new TBLE-02S ESC, with a 5cell, 6v nimh pack (showing 6.5v) I got a reading of 6v output on the 3-way (-> RX) connector, and with a nominally 7.2v nimh stick pack (showing 8v) the reading was 6.1v. On a  7.2v hump back (probably now dead as it showed 2v) I got no reading at all. I conclude that the output is meant to be at the upper end of the “BEC” spec (4.8v to 6v) (rather than the “whatever the battery voltage is” of the earlier TEU101BK kit ESC) & your 1 & 2v are very wrong. 

Are you using any sort of UBEC or other electronics/electrics to muddy the waters? 

My setup is very standard - 380 motor, TBLE-02S ESC, 3300mAH NMH Overlander battery. No modifications and no problems with the car until the summer..

Whole setup hasn't had heavy use over 9 months - 10s rather than 100s of charges. Battery currently behaves as expected. Didn't feel there were any concerns with it. Charges in a few hours. Output terminals measure 8V, both on the plug terminals, and one the back of the socket when plugged into the ESC. I may be able to borrow a battery from someone but might take a week or two until we both coincide at work.

We don't generally use the car in the wet so I wouldn't expect the first ESC to have got wet. The second one only got tried out indoors without even being properly fitted it in place.

I'll get myself a test cable to power the Rx in isolation. I already have some AA battery caddies.

I've been going over the kit again this afternoon. Both ESC seem to be responding to all the setup options as normal. Was able to change them to other options and then back to where I started. Currently both are showing a long green flash on startup, followed by continuous flashing.

Vcc when open circuit is 1V on orginal ESC and 2V on new ESC.

With ESC connected to Rx (but not motor) Vcc - 0V is 0.5V. When bind connector is in place Vcc - 0V is still 0.5V. Same measurement for any combination of ESC and Rx.

Still baffled by the whole thing...


 

Thanks for the tip on building a receiver tester. Some AA caddies and a new cable have shown that both old and new receivers are working fine on their own. LED lit up in each case, and both paired with my transmitter as per the instructions.

I'm now trying to borrow a battery to check that isn't the issue. If not I guess I need a new (3rd) ESC. This time I won't connect it to the motor first. And maybe I won't connect it to the motor at all and just buy a replacement anyway...

Hola,
I just register here as I find this thread which seems to correspond to same issue I have. I have a DT03 which has now few weeks of existence. It came with a 540 Torque Tuned and a TBLE-02S.

I broke 2 receivers in 2 weeks. Samss symptoms when it happens in both case as the original poster describe:

• at some point, while returning to the two channels neutral position on the TX (Absima CR6P), car stop running, then TBLE-02S start beeping  and led flashing green, just like it does when the signal cable is not connected to the RX
• RX led does not light up anymore when connected to the ESC (neither with another ESC, by the way - checked that as well on my son's DT03).
• VCC at ESC rx port is 6.09V (in specs) when there is NiMH connected at power feed port (it is in the specs for both Servo and RXs (first was Absima R6FS, second was FS-BS6)
• Other ports of the RX shows the same 6.09 VCC tension
• First RX issue appeared while the RX was brand new, after 5 minutes of use. I supected the RX to have an issue.
• I replaced the first RX, it worked for 2 packs. in middle of the 3rd one made the same.

I have a third RX, I connected it: It works, I can bind it, and the two channels are working fine. Not sure I go further, as the BEC included in the ESC might be the cause of the issue.

Hypothesis I have in mind :

• both RX are part of a defective lot from Flysky factory (both are basically the same, only branding changes). Possble, but is it really the most probable cause. In general, one can be deffective, but 2?
• servo is consuming too much. I'm thinking this could affect the ESC itself but not the RX, which is supposed to accept tensions up to 8.4V as per their specs. Probability : low.
• As for the ESC issue, it is still showing 6.09V at its BEC port. i'm tempted to think it works but the fact both issues happened when going back to neutral make me think that may be the BEC circuitry is not so independant from the motor feed as it should, and maybe braking issue: if for any reason, a negative voltage appears at the RX end, it would kill the RX as per what I can read out in some areas. Probability : ?

Thinking and discussing with friends, I'm starting to think that ESC deffective might be the most likely cause, because I can't see any other reason. People have burned ESC by using servos consuming too much, but it seems not to be the cause for a RX...

Looking at the issue, and especially considering I'm not alone to see this, I will change the ESC and use another one...

Good luck.
Thanks.


 

I tend to use chinese cheap esc or vintage ones.

Some recivers has 6v as MAX voltage, anything above them will fry them over time.
What amp rating do the servo have?
One solution is to connect a cheap bec with voltage adjusted to 5.5v to power the receiver.
Another is to use a bec to power the servo so the servo will not steal power from the receiver.

I think you need to find the max voltage for the receiver, some do list it on the spec, some don't.
6.09v may not seem much above 6v, but it can sometime be enough too cook the receiver.

Edit: I looked it up and the receiver is rated for 8.4v, so this is a bit strange one...
I have had several bad servos over my rc time, mostly due cheapness and these can make all sort of strange errors, like fully wack to one of the sides, shaking voilently or burn themselves up.
I had aTowerPro servo that almost set my rig on fire, it was too hot to touch after just 5min of testing on my porch and it was correctly adjusted on EPA and there was no binding.
Till this day, I refuse to use Towerpro servos in my vehicles.
I had several of them being bad right out of the box.
Don't like Savöx servos either, noisy, twitchy, thirsty on power and some of them goes crazy after just one drop of water.
Later years I have been using Power HD servos without any issues.

A bad servo can fry your esc and receiver if you are unlucky.

Well. Power is fed from the BEC, not thru the RX. And as far as I understand, the power signal still go to the RX: Channel 1, 3-6 are still powered by the ESC (I can light up leds from there), even though the RX is dead. The way electronics circuits are built make me thinking the circuit is still here and and not burned: so it's likely something else.

For the RX to die, I see two options only:
- over voltage, burns a circuit part somewhere (post the initial soldering). with a NiMH 6 cell and and RX rated up to 8.4V this is unlikely.
- negative tension applied on a component which does not accept it and died: only possible root cause for this is the BEC included in ESC which failed.

As for the servo burning a RX, I really doubt: servo is a slave. Unless I'm misunderstanding, RX is the master. RX sends a signal to the slaves, slaves execute the order. Still, slaves may consume too much power, but again, the way electrons go, it would have burned the source or something in the path to the source : it could have burn the soldering between Channel 2 and RX board, but it has not. It would then burn the ESC, and ESC still works (?). My little knowledge in electricity tells me the most likely source of the issue is the BEC included in the Tamiya ESC, unless I had two deffective RX units one after the other...

I changed the servo, I got a new RX. From there, 2 options

• try with the current ESC: If I get an issue again, this will be for sure the ESC
• get another ESC, and just use this one instead

That being said, I ordered some dirty cheap Flysky RX FS-A3 working in AFHDS 2A (same as the CR6P/GT5), and will have some chance to test further once I get them...