• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 62 subscribers
  • Views 299 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ76PL455EVM: Cannot run GUI "Unable to Open COM port"

Nishil Bhavsar
Prodigy 160 points
Part Number: BQ76PL455EVM
Hello,
Test points V5VAO, VREF, VP1 seemed to be burnt out.
I have tried changing the BQ76PLL455A-Q1 IC, I changed Q17 as well.

I suspect the 5V rail was shorted, but even after replacing many components on the rail, I'm unable to power up the board.
Note: Even D22 doesn't light up. C36 was shorted to ground so, I desoldered it and am waiting for the new part to arrive.
Meanwhile can you please help me figure out component could be faulty?

VIO = 4.73
VDIG = 0.06V
V5VA0 = 4.5
VM =0.024
CHP = 0.040
VREF = 0
VP1 = 0.115
TOP = 49.2
Is VM supposed to be -5v? Currently, it reads close to zero.
TX = 4.97
RX = 5.01
WAKEUP = 0 
FLT-N = 0
.


  • 0
    TI__Genius 17370 points

    Hi Nishil,

    If you suspect there was a short, it can be damage to other components so it would be difficult for us to debug remotely. If you need the board to work and have replaced the IC, your best bet would be to probe the other discrete components to ensure they are still correctly reading. And possible change out the decoupling caps on the rails that are not reading properly. Otherwise is it possible to order a new board? Also did the board work in the first place?

    Regards,

    Taylor

  • 0 in reply to Taylor Vogt
    Prodigy 160 points

    Hi Taylor,

    If you need the board to work and have replaced the IC, your best bet would be to probe the other discrete components to ensure they are still correctly reading.

    I checked all the components, they seemed to be working fine except for R18, it showed 0 Ohms while its value should be 100k Ohms(I didn't desolder and check its value, I checked it while it was on-board). C36 was shorted to the ground. What could have caused it to blow?

    And possible change out the decoupling caps on the rails that are not reading properly. Otherwise is it possible to order a new board? Also did the board work in the first place?

    The cost of a new board doubled to $499! I had bought the same board for $250 in October. And yes the board was working as expected before short.

    Can you suggest some debugging checkpoints which could isolate and identify the issue?

    Regards,

    Nishil

  • 0 in reply to Nishil Bhavsar
    TI__Genius 17370 points

    Hi Nishil,

    If there was an unintentional board short, it is difficult to say as it could be many things - as  I mentioned its its better to move on to a newer board if it cannot be easily fixed as we don't know what all could be damaged if used incorrectly. Did you replace C36? Interesting I thought the board was always $499.

    Regards,

    Taylor