Cyton board not powering up [resolved]
My Cyton board stopped working suddenly and I can't figure out what the issue is. I used it for about an hour for some EEG demos after which it basically went dead. I thought the battery had discharged so I charged the battery and measured the voltage output which reads at 3.88V measured at the board contacts. So, I don't think this is a power issue. (I am powering it with the OpenBCI Lipo battery.)
However, when I turn the board on ('PC'), the LED doesn't power up and I cannot detect the board on the GUI. I might have flicked the switch to BLE when it failed originally, could this be the problem? I read this manual which tells me to press RST if the board stops responding:
https://docs.openbci.com/GettingStarted/Boards/CytonGS/
I tried this but nothing changed. I looked at previous forum posts and this seems to be the only relevant one I could find:
https://openbci.com/forum/index.php?p=/discussion/3755/cyton-not-turning-on#latest
It tells me to check voltage between GND and DVDD. I record this at 1.6V when the board is on. The post above said this should read at 3.8V. Could you please help me as I am a bit stuck.
Thank you!
Todor
Comments
Hi Todor,
Yes, DVDD to GND should be in the range of 3.3V, the nominal regulator value. The fact that you are measuring only 1.6V 'probably' means that there is a component failure in one or more voltage regulators on the board. If this is a recent purchase you should email (contact at openbci.com), which is customer support. Even if this is not recent purchase an email will get an opinion from tech staff and options for repair.
If you have in house techs there, they may want to check out the voltages before and after the regulators on the board. These are shown on the schematic,
https://docs.openbci.com/Cyton/CytonSpecs/
https://docs.openbci.com/assets/images/OBCI_V3_32bit-Schematic-1930fe4303e214795b38b75ba7b35b75.jpg
Regulators are in the upper left 'Power Supply' square area. If your techs have a surface mount rework station, board level repair of regulators would be straightforward as these are large chips.
William
The PC / BLE switch has no effect on operation; both positions power on the board. Suggest trying the 4 AA battery pack, just in case your Lipo battery might have some strange issue under load.
Thanks you William!
I can confirm this was a battery issue. I replaced with a new Adafruit battery and this works now. I just have two final questions:
Thanks again!
Todor
https://eeghacker.blogspot.com/2015/01/estimating-openbci-battery-life.html
The 8 channel Cyton mainboard draws about 50ma. If you divide the milliamp-hours of the battery by 50, you'll get the hours.
All USB power supplies output 5V regulated power.
Thank you!