Power Supply Issues - Undervoltage Warning

[Master_W]

My setup:
Powered USB hub
5v 2A USB power supply
Wired USB keyboard - hub
Wired USB mouse - hub
WiFi adapter - hub
Computer monitor connected via HDMI to DVI
Powered speakers 3.5mm jack
(Everything is connected to a high quality power strip with an on/off switch)

I got a new Pi 2 Model B today after using the original Model B for quite some time. I put NOOBS onto the SD, connected all the plugs and wires and started it up. It immediately showed the low-voltage square rainbow icon and the power LED was flickering. I have a 5v .2A fan connected to the GPIO so I unplugged that and it helped a little, but not much. I never once had this issue with my original Model B. The 5v 2A power supply (name brand Belkin, cost $20 >.<) has a rotating plug that, when turned a certain way, will not work, but when turned correctly it works fine and is what I've been using. The cable came in the kit that my old Pi came in.

I switched to an Anker gold plated fancy cable and the issue went away except for when the Pi first boots up. I also tried plugging it directly into the wall instead of the power strip, but that didn't help. I have a 5.2v 1.35A power supply and when I used that the icon never showed up, but I don't want to continue using that given its specs.

So is my only option to buy a new (preferably one made specially for the Pi) power supply and cable? I know the Pi 2 uses more power, but I see no reason why it shouldn't work properly. Also, while researching this issue I saw something about a certain fuse/chip thing that can get damaged when the Pi is under-powered; is it possible that I've already damaged it?

I really don't want to have to spend more money and wait around for a new power supply to arrive. Any help would be appreciated.
Oh, and my micro SD is a SanDisk 16GB Class 10.

Thanks!

[mosespi]

If your 2A power adapter gives voltage warnings and the 1.35A supply doesn't, just use the 1.35A. No reason not too really, or going about wasting money sourcing a 'better' power supply.

Take those specs lightly.. it already is evident from your testing the 1.35A one holds its voltage better then the 2A. In any case you are likely only taking 0.5A or so from the supply, use what works and don't bother yourself with what they printed on it.

Regards,
-Moses

[MaxK1]

Agreed - use the power supply and cable that works and file the other one away in the "fiction" section. Do you have a link to the Belkin supply you have? Is it the mains plug that rotates or something else?

[FTrevorGowen]

A P2B with minimal USB connected devices** does not "need" a 5V 2A supply. However if you want to power something like a USB HDD from the Pi's USB (with the max_usb_current shared over the four USB ports changed from the default of 600mA to 1200mA) then you would need more than 1.35A to be able to provide the extra current for the HDD.
Trev.
** such as a wired keyboard and mouse, a USB flash drive and (low-power) WiFi dongle.

[Master_W]

Would 1.35A be enough for overclocking and the .2A cooling fan? Everything else is connected to the powered hub. My main concern with it though is that it is 5.2v, and the Pi is rated for 5v, so is it safe to use long term?

The mains prongs are what rotate on the power supply. Can't find a link, bought it at Walmart several years ago.

Thanks for the help.

[FTrevorGowen]

Would 1.35A be enough for overclocking and the .2A cooling fan? Everything else is connected to the powered hub. My main concern with it though is that it is 5.2v, and the Pi is rated for 5v, so is it safe to use long term?

Why do you "need" to overclock? Whilst there was some advantage in doing so for older Pi's (single core) I suspect that's now insignificant given that the P2B has four cores. AIUI a fan only becomes "necessary" with a combination of "extreme" overclocking and a "warmer than average" environment. The Pi's recommended PSU voltage rating is 5V +/- 0.25V so 5.2V is not "out of spec" and, in practice, for a PSU with separate cable, there will always be some voltage drop across the cable. So I suggest that, for now, forget overclocking and the fan and see if it performs well enough for your needs (bearing in mind that a Pi is not a desktop computer replacement, and some overclock settings void the warranty).
Trev.

[drgeoff]

Extra cooling on a RPi gains you nothing in the overclocking stakes because heat generation isn't what limits how fast it will go.