Start up led keeps blinking forever after replacing a DRV chip

Hello all,

I’ve got two vescs connected to a battery one of them wen bad so I replaced it’s MCU(flashed it with th 2.18V firmware) and replaced the DRV chip now when I hook it to a 6S battery it just keeps the startup blinking for ever no matter the battery voltage setting and won’t spin the motor unlike the other vesc which works properly

Any idea for what’s the problem?

Also note the CAN bus IC is removed to prevent any other possible issues.

Thanks for helping.

checked your fets with a multimeter?

How? check what?

video of me checking mine on this thread

If the normal LED never quits blinking, it means your vesc is never recieving commands. The LED will go solid when the motor is active. I’m assuming you’ve connected it over usb and run motor calibration? Does the led go solid when you send a command from the vesc tool? If it works from vesc tool it could be a problem with the servo-input pin not soldered correctly on the mcu or missing passives for the filter circuit on the ppm input pin.

Can’t see or understand a thing of what is ging on there, How do I check wether the FET is good or not? where to probe? what to expect

No I’m telling you nothing other than the motor battery and usb is connected. it can connect to the PC via BLDC and read settings and stuff but will refuse to run the motor with the arrow keys and the same led that makes the blinking thing at power keeps doing that over and over sometimes after power up it won’t even blink after some time.

What color LED is blinking? Red?

Yeah that one.

This means your motor driver is in a fault state. Something is causing it to lock in this mode. You’ll need to look at what fault is being triggered in the data tab to try and target the cause.

You can see in the video where each probe is, one on the power input. You need to check the resistances are all the same for all six. One of mine had failed it was doing all kinds of weird things including corrupting its firmware. It also said drv fault, but the drv was fine. Might not be your problem, but only takes a few seconds to rule out.

Just look at what fault is getting thrown before going to the trouble of probing fets. If its a drv fault then check the fets

Well when I type “faults” in the BLDC terminal if says there are no faults.

Probing all the FETs Drain to source indicates that all resistances are at around 40.9kOhM± 2kOhm

So red led is blinking and faults terminal command says no faults? Strange. Is there any data in the realtime data tab?

Actually now I tryed probing the Voltage regulator and a taltalum blew up in my face gonna have to order the parts to replace it now will check on it later.

Fixed it by replacing the cap and the VR but I’m afraid the MCU didn’t make it :frowning: nothing to replace it with yet.