So I have a TRAMPA battery pack. For testing I connected it to my Flipsky motor controller with the provided 8 pin connector (where one of the ADC pins were connected to a main power switch I presume, based on some documents I found). Then smoke came out of my VESC. No motor was connected at this point.
After unplugging the 8 pin (uart communication) cable I re-powered the VESC. Now a red LED is blinking and VESC tool reports bad driver.
Looking at the board I found 2 hot spots (voltage injection with current limited power supply).
Both IC were labelled as LG33. After some googling I found them to be MIC5231-3.3YM5-TR.
Replaced them but the 2nd next to a big CPU was still getting hot. The caps around the CPU were also shorted. De-soldered the CPU then all the shorts were gone. Soldered on a new CPU, the power regulator chip is now happy, 3.3V rail is good. Getting a firmware on it is still in progress.
But now I got a new hot spot and I am struggling to find the part number of the bad components.
I see 2 suspicious diodes labelled as:
- AE, probably an SMAJ transient voltage suppressor?
- K210, probably a shottky diode but I get too many vague results
You can see them on the screenshots.
Anyone has a schematic or could give me advice? I would appreciate it.
Should I just buy a new one? What did I do wrong?
Bottom of the board:
Top side of the board:
Welcome to the ESK8 forum, @balazs! Wow, that level of repair is above my pay grade. Hope you can find a way to get that sorted tho.
Theres a growing movement for Right to Repair. Maybe theres a facebook group that could give you some advice?
Similar diodes on the right side with some better magnification:
I think the K210 is actually: SOD123 packaged DSK210
And the AE diode is: SMD Diode SMAJ5.0A DO-214AC 5V AE TVS diode. But in the PDF the markings table column says differently. Still confused by this one.
That looks like some kind of input filter to the regulator, those parts may get hot if there is a short later in the system.
I agree that is likely a 5V TVS you found with the AE code, this would be clamping the 5V from the DCDC before the LG33 regulator and DRV8302. Chinese components often have different logos on them, as they have other smaller manufacturers branding chips, so the logo being different isn’t much of an issue.
You may want to check the DRV8302 MOSFET Driver (large SOIC on the bottom), as this connects to VBAT and 5V, and that failing could be causing shorts in the supplies that explain this issue.
Here is the original vedder schematic the Flipsky is designed from, but it doesn’t have the power stages you might need, and Flipsky may have changed the design as well. Maybe it helps you to understand what you are looking at better.
I removed the 5V TVS diode and I think the short is gone. Checked the caps around both DRV8302 driver IC and nothing is shorted so finger’s crossed. Checked all MOSFET output switches and they also seem to be good, no shorts.
Since ordering the SMAJ5.0A TVS diode in my country costs a fortune (15 euro for 10 piece) and local shops don’t know what it is (or don’t want to), I ordered from china Should arrive in a month.
I’m glad to hear your driver chip looks okay, those are expensive ICs. But a shame you have to wait so long to test it. You could likely run it up for bench testing without this part fitted, as it’s just for voltage stability, and the other one (should be in parallel) keeping the 5V rail clamped.
Jsut don’t plug your BMS cable back in, as there must be something incompatible with that pinout. Esk8s have been evolving rapidly over the last few years, and they all use the same JST plugs. I suspect you have full battery voltage on that connector, and since the comms connector in the Flipsky is only meant to be 3.3V logic/ADCs, that could have backdriven a high voltage through the CPU-3v3 Regulator-TVS diode.
I blew up half a Flipsky dual on it’s first ride (unlucky drop of water got into the case), your post has given me the entusiam to find and fix it too!
- Programmed the STM32F405 on a pyboard as the ST-LINK was unable to detect the CPU when it was on the VESC PCB
- Now both red LED is blinking (previously only one was blinking), that would mean they both see an error condition? This might mean that those are working now as they should.
- Got a 5V TVS protection diode. After replacing it it is still getting warm (but the short is gone on the 5V rail). As if the DRV8301’s buck converter would not function. Maybe I need to connect an oscilloscope to the diode next to it an look for a square wave. Cannot measure shorts on any caps on the board right now. I think the probability of having to replace DRV8301 is getting higher. But it is such and expensive part at the moment.
What else should i check?