openinverter forum

I'm getting incorrect voltage readings on 3 of my boards and 2 dont even power up.

I swapped headers and this may have led to the issue.

I've checked Fet readings and resistors. The 3 working boards I have appear to match the 3 that are giving incorrect readings and the 2 that won't start.

I can flash firmware to all via the STLink, all are running the 0.25.25 FW and see flashing LEDs on all of them after doing so.

I've got continuity from pins and traces seem to be unbroken. I've checked diodes and they seem to be ok... is there any guidance anyone can offer in getting these working again?

Thanks

Jacobsmess wrote: ↑Tue May 13, 2025 8:00 am The 3 working boards I have appear to match the 3 that are giving incorrect readings and the 2 that won't start.

Jacobsmess wrote: ↑Tue May 13, 2025 8:00 am all are running the 0.25.25 FW and see flashing LEDs on all of them after doing so.

Contradiction Please specify "won't start"

Sorry so I've got 10 boards in total.
4 (not 3 as previously stated) work fine
3 give incorrect voltage readings but otherwise appear to operate fine, no errors.
3 that don't power up at all using the 12V connection header (and enable etc.) But can be connected to using an STLink and the LED lights up when connected to and flashes after the FW is written.

I think the incorrect voltage readings were present prior to me swapping the headers.

Images of 3 of the boards spot values that are presenting incorrect voltages....
U5-U8 U2-U3 U2, U5, U10-U11

Any ideas on where to look to address this? Thanks

Any suggestions of where to look?

You're not gonna get around reading this thread: viewtopic.php?t=5665

johu wrote: ↑Sun Jun 08, 2025 6:13 am You're not gonna get around reading this thread: viewtopic.php?t=5665

I have read through it before, I don't remember seeing the same problem I was having but will revisit. Apologies if I'd missed something.

Indeed the "incorrect voltage readings" are differently incorrect than discussed in said thread. They essentially read 0. Have you checked whether the cell voltages make it to the board at all in those positions? Doesn't look like failed FETs.

The boards that don't power up must have a broken 5V regulator, I suppose. You can try feeding stable 5V into the current sensor 5V rail and see if they light up. If not it's the 3v3 reg that's broken

ok thanks, I'll check on the boards with the wrong readings, I'd half assumed as I have continuity from the cell tap input to the resistor legs that I should be good but will check voltages also, hopefully its just a dodgy soldering job, I'm 95% they were ok until I changed the header but I'm not 100%.

I'll also check the regulator on the dead boards. Thanks for the guidance!

I've ordered some replacement 5V regulators as I think a couple were broken. I've checked the voltage at the first resistor cell tap leg on one of he board that was giving incorrect readings on 3 cells and the voltage was correct all the way (3.85V).

I'll recheck the fets but I'm fairly certain they all read correctly as oer your instructions on the other thread (0.65V across the Drain to source i think except a couple maybe Q1 and Q5 that read 0.73v)