So I've had a closer look at this.

I have tried to simulate a weak power supply by limiting the voltage and current on my lab supply to values at which I expect stuff to barely work, namely 4.8V and 0.3A. With the latest build I get 0.19A current when the system is up, between 0.2A and 0.27A during boot-up, and a brief spike in which the current runs into the limiter.

When the system does not boot successfully, I get the typical issues that people have complained about, such as the garbled color screen (which is the firmware code rendered in 32-bit RGB, BTW), a white screen, a black screen or a hang at the BE logo.

There are two things that can be done to make the system work sometimes when limited to 0.3A and reliably when limited to 0.35A. The first is to disable the EHCI controllers. These are currently unused, and not bringing them out of reset saves just enough power for the system to survive the current spike and boot up successfully. I am not going to do that, however, because the EHCI controllers are required for USB2.0 support, and that is likely to happen at some point in time, and when it does I don't want to deal with complaints from people with marginal power supplies whose systems won't come up any longer.

The other possibility, and what I would suggest to people having issues, is to provide some support for the 3.3V line of the Orange Pi. Adding a substantial capacitor between pin 1 (3.3V) and pin 6 (GND) -- I have tried 1000 uF because that's the largest I happen to have lying around -- is good enough to make the system boot up reliably even with a supply that is way below specifications. It is worth noting that bypassing the 5V line does not do anything, which is why I believe this to be a design issue in the OPi power supply circuitry.

I would like to point out that I do not recommend running Engine BASIC on the H3 with a sub-par PSU. Any change in the firmware, such as exploiting additional CPU cores, new device drivers, or attaching more USB devices will have you run into trouble. If you have a supply that should be good enough on paper but doesn't work well in practice you might want to give this a shot, though.

    uli Thanks a lot for the research and info, Ulrich!
    The only PSU I can trust is the one sold by the same people that sell the OPi. I've had mix results with others, specially with USB based adapters. I've decided to use the only one I trust, since I have no problems at all when using it.

      2 months later

      Just a small addition to this thread. I recently found a couple of Sony PSPs that I thought were long lost. Amongst the stuff were three original PSP power supplies. They happen to have to correct voltage & polarity and work very well for both the Orange Pi Lite and Orange Pi PC that I've tried them on over the last week.

      4 months later

      Aaahhhh!!! I think I may have blown up my brand new Orange Pi PC. :^(

      My first attempt to power it was through the USB OTG connector. After trying a couple of different USB chargers and not getting any sort of LED on power up I started to think things were wrong. I had forgotten reading about the fact that the USB OTG does not pass power to the Orange Pi.
      So I started searching the house for a 5v power supply with enough power. I remembered I had one that could have the connector changed, but I couldn't find the associated connectors. So I found a connecter from a different variable power supply and used that, after researching carefully to make sure that I set the polarity of the TIP correctly.
      Plugged it in...nothing. So at this stage I decided that I better measure the polarity to make sure that it was OK...it wasn't. The markings on the connectors of the power supplies were not consistent, so I swapped it around and measured it to be sure. I didn't think about the voltage floating high, I figured that the power supply was unloaded...WRONG!
      I had connected a 12V power supply to my new Orange Pi PC in both polarities. (T_T)

      So...my question...does the Orange Pi PC have any sort of input protection, or have I fried it?

      My only consolation, if there is one, is that I'm not the only stupid fool to do this.
      Orange Pi Forum

      If you are in need of an H3 to use, I would be happy to send you one gratis.

      • Hawk replied to this.

        painintheworld, that's a very generous offer. I still have my Tauon PC-1 to use, and I am going to build the SDL version on my desktop PC to document the process, and also use for some development. (I've only installed it on a Linux Mint laptop so far.) I am planning on ordering another Orange Pi PC board still, as I want to try and make a standalone BASIC Engine PC like the Tauon, but with a cheap mechanical keyboard.
        Are there alternate cheaper H3 boards that I could try?

        • Hawk replied to this.

            The cheapest thing I've seen in the last several weeks has been the Android TV box in the other thread, at $29.99 USD.

            Far and away my favorite thus far has been the Libre H3 device. Hands down. It was $35 on Amazon and there is none available on the U.S. Amazon, at least that I can see. They do have the H5 version, though it is an Amlogic S905X, despite Libre's name. There is the NanoPi M1 for sale on eBay at $25 (some sellers are $30 or so) plus postage. The Orange Pi models all seem to be $30 on up to $40 on eBay these days. The price on Alibaba isn't as bad...if someone wanted a lot of 10 Orange Pi PC 🙂

            Would love to see what you had in mind for affixing a Pi/H3 SBC to a keyboard! Do you plan on using 3D printed parts? Amazon had a flash sale on Prime Day on this keyboard, for $21 USD. My assumption was that it would be passable for the BASIC Engine and similar usage, but it has turned out to be much, MUCH better than anticipated. Had I known it was punching that far above its $21 price tag, ole Mark would've order several. Link >> `https://www.amazon.com/gp/product/B07WR9YCKK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

            Hawk Great news...I didn't blow my Orange Pi PC up after all! 😃
            Maybe I didn't leave the power plugged in long enough, what ever, I've finally found a 5V power supply in all my stuff that will power it up correctly. It booted straight into BASIC Engine at 800x600.
            Very cool.

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