When the board is under load, I also seem to get low voltage readings from the out side of the polyfuse. When running Quake, I've seen voltages as low as 4.55V (while the supply-side is reading 4.98V).
There seem to be other users on the Raspberry Pi forums with similar problems. I'm wondering if there was a bad batch.
I added my information to http://elinux.org/RaspberryPi_Boards#Ha ... Frevisions (I'm currently the last entry - the BS1238 owned by Balefrost).
I don't know what else to try. Somebody suggested sticking it in the oven to improve the solder joints (they said that there were some BGA soldering issues with the Pis). Any thoughts?
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Board Version:
BS1238
With extra header P5, missing fuses F1 and F2, and with mounting holes just like BS1233
Weird stability problems. Can build Quake3, and can play it for a little while, but eventually locks up (black screen, loses ethernet link). Putting it in the Adafruit case seems to exacerbate the problem.
Highest temp measured by vcgencmd measure_temp is 53.5C. Last measured temp before lockup was 53.0C
Problem occurs with both the Adafruit power supply as well as my Nexus 7 2A supply.
Tested with at least 3 different Micro-USB cables.
Tested with the 4GB Dane-Elec Class 4 MicroSD card from Adafruit, as well as an 8GB Class 10 SanDisk full-size SD card.
Voltages:
Idle, with HDMI only
- 5.06V (polyfuse in)
- 4.82V (polyfuse out)
- 5.04V (polyfuse in)
- 4.77V (polyfuse out)
- 4.98V (polyfuse in)
- 4.55V (polyfuse out)