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Issue with Voltage Drop when Using Controlblock



  • I am using a Controlblock with a Raspberry PI 3 B. I have the Controlblock (http://petrockblog.storenvy.com/products/13969497-controlblock) plugged directly on top of the Raspberry Pi with the GPIO pins. I have the raspberry Pi overclocked in order to be able to run N64 Roms. Here is my current config.txt

    arm_freq=1250
    gpu_freq=500
    v3d_freq=525
    gpu_mem=256
    core_freq=500
    sdram_freq=500
    sdram_schmoo=0x02000020
    over_voltage=5
    over_voltage_sdram=4

    I am measuring the 5V from the GPIO pins (GND and one of the 5V).

    With the Controlblock connected, and I run a simple stress test.

    while true; do vcgencmd measure_clock arm; vcgencmd measure_temp; sleep 10; done& stress -c 4 -t 900s

    I have tried this with two different power supplies.

    https://www.amazon.ca/gp/product/B00IKUYANK/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 (Mine was an older version, looks different, that has 18AWG wires)
    With my 3.5A 18AWG 5V adapter I get the following results.

    I measure around ~4.8 V with intermittent drops around ~4.7V and then rises above ~4.8V before it repeats. This causes the lighting bolt icon to appear on the screen and the clock speed to constantly drop/cycle.

    When I have the Controlblock card removed, just the Raspberry PI, with the same settings/test.

    I measure around 4.94V with intermittent drops to around 4.88V, with no lighting bolt.

    https://www.buyapi.ca/product/wall-adapter-power-supply-5-25v-dc-2-4a-usb-micro-b/
    With my 5.25V 2.4A adapter I get the following results.

    I measure around ~4.9 V with intermittent drops around ~4.7V and then rises above ~4.9V before it repeats. This causes the lighting bolt icon to appear on the screen and the clock speed to constantly drop/cycle.

    When I have the Controlblock card removed, just the Raspberry PI, with the same settings/test.

    I measure around 4.96V and appears to be fairly steady.

    I know why the lighting bolt appears, as it indicates a voltage issue when dropping below ~4.75V.

    I am using Raspbian GNU/Linux 8 (jessie) w/ Retropie 4.2 (issue occurred on 4.1 as well.)

    Linux retropi 4.4.50-v7+ #970 SMP Mon Feb 20 19:18:29 GMT 2017 armv7l GNU/Linux



  • You need a power supply with a little more amps to push the voltage



  • @space-cadet I have purchased three power supplies, all with increasing Amp and Voltage. If you have a power supply in mind that can push more than 5.25V at 2.4 amps, I would appreciate it. Also have tried a 5v at 3 amps.



  • For some reason, this seems to have changed in the last few months. I updated ControlBlock service and latest Raspberry Pi (Retropie) version and the bolt appeared. I only had it months ago when using a poor quality USB cable, but now even with a really good USB cable it now appears. Very strange.

    Could the ControlBlock voltage drop have increased with more recent software /service updates?



  • From measuring the USB power drain from the power supply (inline USB measuring) the ControlBlock2 is pulling 5.06V and 0.421A when the yellow warning is in the upper right corner. I didn't measure the 5V output from the Pi or ControlBlock itself as I don't have my multimeter here.



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