You are here

Dead VESC6 due to shot from UBEC, repair possible?

10 posts / 0 new
Last post
Boesila
Offline
Last seen: 10 months 1 week ago
VESC FreeVESC Original
Joined: 2017-05-24 12:24
Posts: 18
Dead VESC6 due to shot from UBEC, repair possible?

Hi all, 

 

one of my two VESC6 is dead and I hope someone could help me to repair it. 

It was basically my fault that the VESC ist broken. Here are some details how this could happened.

I installed a DC-DC step down converter (UBEC, 50V -> 5V) to my 12s battery to power some lights and an arduino nano as receiver for my remote http://www.electric-skateboard.builders/t/simple-3d-printed-nrf-remote-arduino-controlled/28543. The step down converter is a really cheap one from aliexpress https://de.aliexpress.com/item/DC-DC-Buck-Converter-KIT-Adjustable-Power-Supply-DC-DC-Step-Down-Adapter-3A-LM2596HVS-LM2596HV/32803672846.html. First every thing works fine, I drove about 100 km without an issue and a lot of funlaugh. Than suddenly I didn't get any connection between the receiver and my remote. I checked the DC-DC converter and measured 0 V at the output (normally it was adjusted to bring 5 V out), so this cheap converter was obliviously broken.

I tried to figure out which part on the converter board failed and than it happens that I cause a short with the tips of my multimeter so that I get 48 V at the output of the DC-DC converter. 

Like I said the DC-DC converter was connected to an arduino nano. The arduino was conected with 3 wires to the VESC: SERVO, TX and RX. 

I know I was stupid that I did the check up with all parts connected and with power onfrown  After this accident the arduino was srcap but much worse the VESC do not show any sign of life when I power it on... no LED is blinking no connection to the PC possible cryingcrying

 

Do anybody have an advice what I can do? Maybe I can send the broken VESC6 to someone to repair it? Maybe I should open it to see what is broken? 

 

Best wishes 

Boesila

benjamin
Offline
Last seen: 21 hours 3 min ago
Joined: 2016-12-26 15:20
Posts: 369

It is most likely that the microcontroller in the VESC broke, but with a bit of bad luck the entire 3.3V net could have experienced the high voltage. This can destroy almost every component besides the passive ones.

You can measure if there is a short in the 3.3v net and the 5v net (most likely the 3.3v net is shorted). If there is a short and you have a hot air soldering station you can take the vesc apart and carefully desolder the STM32F4, clean the pads with some flux and solder wick and measure if the 3.3v net is still shorted. If it is fine, it is likely that it works if you just replace the STM32 and upload the firmware over SWD.

Boesila
Offline
Last seen: 10 months 1 week ago
VESC FreeVESC Original
Joined: 2017-05-24 12:24
Posts: 18

Hi Benjamin, 

 

Thanks for your reply. 

I measured the 3V and 5V System... 3V is shorted 5V ist okay. Than I desoldered the STM32 and the 3V wasn't shorted anymore, so maybe I'm lucky :)

I ordered (get sample from st.com) a new STM32 and will replace it. Hopefully that works... I'll keep you updated 

 

Best, 

Boesila 

Roger Wolff
Offline
Last seen: 3 months 1 week ago
VESC FreeVESC Original
Joined: 2017-05-24 12:27
Posts: 202

Yeah. My STM32's also short out when bad things happen. I don't fully understand how in my case a blown half-bridge can cause the CPU to get fried, but it's happened twice. 

Boesila
Offline
Last seen: 10 months 1 week ago
VESC FreeVESC Original
Joined: 2017-05-24 12:24
Posts: 18

So... I'm finished with soldering the SMT32, but I can not upload the firmware like it is described here: post #25 https://vesc-project.com/node/62

Can't get any connection to PC over STM32 ST-LINK Utility (Windows)surprise

What can I do?cool

Danny Bokma
Offline
Last seen: 2 days 2 hours ago
VESC OriginalVESC Platinum
Joined: 2017-05-24 12:11
Posts: 52

The STM32 only needs 3.3V and GND on its power pins and a correct connection to the st-link to be recognized by the ST-link utility (having a decent programmer helps as well),  could you check that your soldering went correct, 3.3V is applied to the uC and that the SWD, SWCLK, RST and GND are connected? When using an original genuine ST programmer you also need to connect the target voltage pin, in your case the 3.3V (this is usually not the case with chinese programmers).

Boesila
Offline
Last seen: 10 months 1 week ago
VESC FreeVESC Original
Joined: 2017-05-24 12:24
Posts: 18

Thanks for the support Danny. You were right the soldering was not perfect, after some retries I was able to upload the firmware with STM32 ST-LINK Utility. Connection to VESC-Tool was working to. I updated the bootloader and the firmware to newest version. After that I run the motor detection (incl. hall sensors) without an issue...I was so happy laugh​ .

Than I connected my receiver (arduino) to the SERVO and UART port. And than something very strange happens, the input voltage which was displayed in the VESC-Tool drops slowly from 49 V to 2 V surpriseangrysurprise and the red LED was blinking. I shut down the power supply and afterwards restart it... but than the VESC didn't start in the right way, only blue LED is on continiously,  green LED is on continiously after around 5 sec, and red LED is blinking also after around 5 sec. Connection to VESC-Tool is not possible, even without connected receiver. The receiver is okay, it works perfect with my other VESC6.

I disconnected everything and gave again some hot air on the STM32 pins, to make the soldering joints more better. 

Than I restarted the VESC without any connected items (only battery and USB), and it started nicely and I was able to connect it to VESC-Tool again. Than I connected the receiver again, same strange problem like I described above happed once more. 

Again I disconnected everything,  gave some hot air on the STM32... and than the VESC was booted again the right way (to prove that strange behavior I tried that once again, with same result). 

Than I tried to make the connection via CAN Bus to my other VESC6, but it was not possible to get a working connection.

I guess anything else broke at the accidentally short (see post #1).

 

Also I measured some connections:

SERVO pin to STM32 pin 58 --> 100 ohm 

GRD to 3,3V / VCC --> 3,3 V

GRD to 5 V --> 5,1 V

CANH / CANL pin to U4 (CANH /CANL) --> 0 Ohm (according to schematics)

U4 (TX / RX ) to STM pin 61 / 62 -->  0 Ohm (according to schematics)

 

Any idea what part I should replace next? Or is it more possible that the PCB is broken and I have some leakage currents or something else? Can somebody maybe explain what's the cause of this strange behavior?

 

I'm happy for any help, hopefully I can get it running again... I want to drive my dual setup again, one motor is not enough power ;-)

Boesila
Offline
Last seen: 10 months 1 week ago
VESC FreeVESC Original
Joined: 2017-05-24 12:24
Posts: 18

Hey guys, 

 

I'm not able to repair the VESC6. I guess the PCB is broken and I don't know where I can get a new one from. 

So currently I'm thinking about to buy a VESC 4.12, FOCbox, esk8 controller or something similar to replace der dead VESC6... Would it be possible to run a dual setup with one  "VESC 4.12 - based" and one VESC6.4?

Best wishes

hexakopter
Offline
Last seen: 2 weeks 2 days ago
VESC OriginalVESC Platinum
Joined: 2017-05-24 12:13
Posts: 68

Hey boesila,

sorry to hear that. Sounds like you tried everything to repair it yourself. Whats your plan with the dead VESC 6 now? Throw it in the bin or let it rest in the drawer? Before you do that feel free to contact me and I will send you some bucks and give it another try repairing it. I like tinkering with electronics and that sounds like a challenge. Would be a real pity when just ends on the electronics cemetery.

To your question regarding the CAN connection. I think the VESC 4.12 uses a different CAN transceiver than the VESC 6.4. (TI SN65hvd232 vs. NXP TJA1051TK3) I haven't looked deeper into it but it looks like the  transceiver of VESC 4 gets 3.3V input voltage and the VESC 6 one 5V. I haven't looked in the datasheets but that is the first thing I noticed so maybe there would be a level issue. So that you don't brick your next devices one should look into that deeper before just testing it I think. Maybe someone else already tested it or knows more.

benjamin
Offline
Last seen: 21 hours 3 min ago
Joined: 2016-12-26 15:20
Posts: 369

Can should work between any vesc hardwares, it is universal. If can is the only thing that is not working on the dead vesc6 it could be the can transceiver. I have seen it die without causing a short.