Firmware update caused sensor board fault?

Troubleshooting
1

Hi there,

I am running a v3 with a sensor expansion and a pro output expander. Everything has been working as expected, until I finally did the OTA firmware update for the main board today.

I don’t have a record of what version I updated from, but it’s now on v3.70. The PB was purchased in 2026 and is hardware v3.

After the update, the sensor board is not showing up in the Expansion UI note, and is not accessible from any pattern code. The light variable remains unset:

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image286×231 13.6 KB

I have examined the following possible causes:

  • Solder joints – I reflowed all the solder on the board headers and checked continuity with a multimeter from test pads on each board. No problems.
  • 3v3 - I verified the presence of 3v3 on the sensor board (with correct polarity) using a multimeter.
  • Visual examination - there don’t appear to be any components blown-up on the sensor board
  • Power cycle - power cycling the stack or the output expander as a whole does not resolve the issue
  • Backup/Restore - had no effect

I did blow a 5A fuse on the output expander recently, but I’m pretty sure I used the sensor board since then, and besides, I can verify that the 3v3 power electronics on the board sandwich are working properly.

I have attached a firmware backup archive should it be relevant.

ALLY-PIXELBLAZE-01.pbb (715.4 KB)

In any case, let me know if there is a way to downgrade firmware or if this is a known issue of any kind. Thank you so much!

Ziggy

2

I would think it’s very unlikely to be the version. If you post photos I could help eyeball connections.

You can try downgrading. 3.70 has some important big fixes though!

Search for the “release” tag on the forum and download the pb32 update file. Then upload this to the /recovery tool. Eg the previous release Release V3.67 - bugfixes

A few ways to help troubleshoot where the problem is.

The sensor board will transmit data when powered. The TX pin on the Sensor Board connects to RX on Pixelblaze. A multimeter won’t be able to see the fast transitions since it’s digital but should show something and it shouldn’t sit exactly at 0v or 3.3v.

You can also measure power on the analog inputs header. That should also show 3.3v.

3

Hi Wizard, thank you for your quick reply.

I have attached several detailed images showing the connections as best I can.

I did check the voltage on the Sensor TX pin and see a low value only, close to 0v.

I just checked GND-3v3 on the analog inputs header, it is present.

I am working on getting access to an oscilloscope so I can check the rx/tx more closely.

IMG_0507
IMG_05073024×4032 1.96 MB

IMG_0508
IMG_05083024×4032 1.7 MB

IMG_0506
IMG_05063024×4032 2 MB

IMG_0505
IMG_05053024×4032 2.24 MB

4

Connections look solid. SB might have died :frowning: There’s a small chance the SB is ok and the PB input pin is instead damaged or something. A scope would tell for sure. Either way I can get you a replacement.

Shoot me an email with order details wizard@electromage.com