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I am using Raspberry Pi 2 with Raspbian OS.

It is connected with usb wifi adapter, a bluetooth adapter for keyboard and power supply is 5v 2000mA AC/DC adapter.

RPi goes blank periodically for a second and comes backs to normal on LG TV 32LD340.

It is strange but when I plug my fan on 5v pin. It stops blanking. But sound output stops. After unplugging it makes display blanking again.

I tried bootconfig, even set HDMI group and mode to 1. But it also goes blank in that case. Currently hdmi_mode=39 1360x768 60 Hz

On Samsung it works well

How can I solve it?

Switching to more stable adapter with 5.v 1A solved the problem. I am still testing. Now I am using

huawei traveller usb charger Model hw050100E2w
5.0V 1A

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It could be possible that you are overvolting your Pi, and when you plug your fan in it drops the voltage. Have you tried using a different power supply? Also, have you tried using a different HDMI cable/display?

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  • Currently I am testing on Samsung. It seems working normal. – qwr Dec 19 '15 at 15:00
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    Using more AMP does not drop the voltage! Increasing the impedance of the entire circuit may do so but technically the Pi does not run on 5volts, just on 3.3 and 1.8v. But, the actual HDMI does run on 5v. Maybe he has a grounding problem between the Pi and the TV. Bad connection or ground loop. – Piotr Kula Dec 19 '15 at 23:05
  • @ppumkin The Pi needs to be supplied 5v into it's micro usb port, I understand that the circuitry steps it down before actually using it, but supplying less than about 4.75v risks undervolting your pi and supplying more than about 5.25v risks overvolting it. – Patrick Cook Dec 19 '15 at 23:15
  • @ppumkin I do agree with you that the problem is most likely not the Pi's fault but the connection to the TV or the TV. – Patrick Cook Dec 19 '15 at 23:16
  • Yea, the statement about the AMPs was incorrect, that was all. The HDMI works on 5V, so the risk is the TV is rejecting the HDMI connection because the voltage negotiation is incorrect, and the TV is protecting it self. The Pi will still run becuse the linear 5v to 3.3v can handle higher inputs no problem as the output will always be 3.3, which the SoC needs to run. 5V is used for HDMI and USB only. That is why the Pi GPIO is 3.3v and not 5V. There is internal protection on the Pi against too high 5v to protect USB and HDMI devices. – Piotr Kula Dec 19 '15 at 23:21
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Heating might be reason for display going blank. I have observed it on my raspberry pi as I was not having heat sink. Check if your raspberry is hot when display going blank. And make sure you keep it cool with heat sinks.

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  • I tested it with samsung several hours.it worked well – qwr Dec 20 '15 at 9:29
  • I had heat sinks too – qwr Dec 20 '15 at 9:29

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