Repair thread: symptoms and solves

Proffieboards
21

no help shorting BATT+ and 5V.

L1 is non-polar, yes?
Swapped that too. still no good
Keep in mind these are donor board parts so far, so no promise parts replaced are good. Just looking to see if I missed a culprit.

22

L1 is a pretty simple component, and if itā€™s broken it usually measures as not connected. And yes, it doesnā€™t have a +/- side.

Maybe there is a short in/under the amp? That could make the 5v not work, and it would also make there be no sound at all I think.

23

Swapped L1 coil. No change
Swapped U1 amp, no change. Still no sound, no 5V.
Replaced U1 amp with Brand New Partā€¦Still nothing :frowning:
Not sure what else to try.

24

Good question, thatā€™s a weird one.

25

Board #8 - Proffieboard v2.2 Black, no branding.

Symptom(s):

  • No response at all.

Inspection:

  • Desolder and clean all pads
  • No 3.3V on 3.3V pad.
  • Suspect U60 3.3v regulator bad.

Fix:
Replace U60 3.3v regulator.

  • Board lives, but instantly reporting low battery and Serial Monitor goes grey.
  • Force upload of known-good test
  • All working well.
1 Like
26

Next: - uh, well this oneā€™s likely just a donor board now. Yikes!

Screen Shot 2022-05-28 at 7.43.28 PM
Screen Shot 2022-05-28 at 7.43.28 PM1370Ɨ786 208 KB

3 Likes
27

holy snikees batman, thats a poop show

28

Board #9 - Proffieboard v2.2 Black, KR Sabers.

Symptom(s):

  • No boot sound, no lights, no Port in Arduino.

Inspection:

  • Desolder and clean all pads
  • Has 3.3V on 3.3V pad, however, no voltage on SD power pad.
  • Same when supplying battery power.
  • Suspect Q7 bad.

Fix:
Replace Q7 dual FET.

  • still no 3.3 on pad 4 of Q7ā€¦2 bad ones? (replacement was donor)
  • Brand new Q7 part ā€¦still no sd_vdd. But noticed 4.9V on BATT+ everywhere with USB power only.
  • Removed D61. Backfed voltage all goes away, but still no sd_vdd 3.3V from Q7.
  • No hot CPU

Stumped. Any pointers @profezzorn?

continued

Well, it seems the CPU isnā€™t happy. Maybe that gets swapped at a later date.

29

So, sd_vdd doesnā€™t get turned on until the CPU boots.
If the CPU had a completely botched programming, or no programming at all, it could potentially leave sd_vdd off. Of course that would also happen if the CPU is dead. Another possibility would be a short under the pull-up resistor that keeps sd_vdd off by default. Have you measured the voltage on the sd_vdd gate?

1 Like
30

Thanks. Yeah, no forced upload to bootloader working. I donā€™t think itā€™s booting.
RN5 tests clean, if thatā€™s the resistor you mean.
Iā€™m measuring 0V at pin 6 on Q7, here.

KR_Orange_3.3v_shorted_to_GND copy
KR_Orange_3.3v_shorted_to_GND copy953Ɨ502 102 KB

31

Iā€™m saying you should also measure sd_power_en (Q7 pin 2) to see if itā€™s trying to turn the power on or not. If itā€™s trying to turn it on, but itā€™s not working, then the problem is on the Q7 side. If itā€™s not trying to turn it on, then the problem is on the RN5/CPU side.

Also, measuring sd_vdd can be misleading, because it becomes nearly floating when off, and when itā€™s floating it could essentially measure as any voltage. Same thing happens to the LED pads when they are off. Adding a resistor between the two measuring probes can give you more predictable results when when youā€™re measuring something that might be floating.

1 Like
32

Ah. Yes I measured 3.27V on pin 2. Plus itā€™s a brand new Q7, so it seems like it should be working.
3.3V on SD power is a symptom. The board still isnā€™t booting. Could it boot without Q7 feeding out 3.3V on sd_vdd, or is it dependent on it?

33

Itā€™s a pFET, so it conducts when the gate is low.
3.27v on pin 2 means that the cpu isnā€™t pulling the sd_power_en low.
The CPU should boot just fine without sd_vdd.

34

Ah. ok thank you.

35

And here I am thinking Iā€™m the worst.

36

Board #10 - Proffieboard v2.2 Black, no branding.

Symptom(s):

  • Board does not boot from battery power, USB works fine.

Inspection:

  • Try boot from USB, then remove USB and leave only battery power.

  • Board runs until battery power removed. Then needs USB again to boot.

  • Suspect D61 bad.

Fix: Replace D61
All working well

1 Like
37

Board #11 - Proffieboard v2.2 Black, no branding. Broken reset btn.

Symptom(s):

  • No response.

Inspection:

  • only 1.8V on 3.3v pad.

  • Suspect U60 regulator bad.

Fix: Replace U60 with donor

  • Still only 1.8V on 3.3v pad.

Replace with brand new U60.

  • Now LESS . 0V out of U60.

  • Only 1.2v on backside of D62 D63 D61, regardless of USB or BATT power.

  • Learned to test diodes properly with multimeter diode mode. Bad D63 and D61.

Replace with donor board diodes that test good.

All working well !

1 Like
38

Ah, yes. Keep talking repairs to us, baby.

40

4 posts were merged into an existing topic: Test rig assembly and use

41

Board #12 - Proffieboard v2.2 Black, KR Sabers.

Symptom(s):

  • No button 1 response.

Inspection:

  • All works fine except button 1 pad.
  • Serial Monitor shows both powerButtonPin 21 AND auxPin 23 to be shorted.
  • However, AUX button 2 and AUX2 button 3 both work fine.

Fix: None without CPU swap I believe. Useable enough with just one less button pad.

2 Likes