Brian's Brain

Two weekends ago, I noticed that my Apple TV was outputting wonky graphics from its UI, along with heavily distorted images when I attempted to play back video clips. For those of you unfamiliar with the product's hardware and software underpinnings, it's basically a headless Mac running a custom version of OS X, and with TV-friendly composite, S-Video and component video outputs (along with HDMI, which is what I use) instead of the traditional VGA. It's intended to be constantly powered on; even when you manually put it in standby mode, significant portions of the system remain fully operational. If I unplugged the Apple TV for several days, its display would be fine for an hour or few, depending on what I subsequently did with it, but sooner or later its issues would re-emerge. Obviously, a heat-related marginality was to blame.

Apple TV employs an archaic Nvidia GPU along with a low-performance (albeit low power consumption) Intel Pentium M processor. I took the system (which had only a few months left on its AppleCare extended warranty) to the nearby Reno Apple Store that Sunday evening and, without even powering it up to confirm my report, the Genius Bar representative offered to swap me for a brand new replacement unit. His speedy, positive response leads me to suspect that my situation isn't unique. He didn't have one in stock, but the order he placed that night resulted in a new Apple TV in my hands three days later. In retrospect, I didn't try any of the other video outputs of the faulty unit so I don't know if the issue was with the Nvidia chip or perhaps instead with the Silicon Image HDMI transmitter. Nonetheless, it was a video subsystem-centric flaw. since I was still able to stream audio to the unit and otherwise tell that it was operational.

I'm also having a graphics-related issue with my MSI Wind U100 netbook. Sometimes (but not always) when I power up the system or bring it out of standby, I end up with an illegible display (specifically: the integrated LCD) that's reminiscent of what happens when you try to drive a progressive-scan video input with an interlaced video source (or visa versa). It's not a Windows XP-centric problem, because the garbled graphics are present even at the initial BIOS boot-up screens. Again, however (and as with the earlier Apple TV situation), I can tell that the system is otherwise operating normally. This fact tthereby leads me to not suspect the GPU itself, since it's integrated within the system's core logic chipset.

I'd initially thought that the Achilles' Heel was the interconnect cable presumably running from the system board to the LCD bezel through the hinge. But varying the bezel position had no effect. By accident, however, I discovered that if I repeatedly turned the system upside-down while it was running, I was sometimes able to sustainably restore the display function...at least until I subsequently shut down the netbook or put it in standby again. I haven't yet attempted to connect an external display to the system's VGA output; that's my next debugging step. I'm a bit baffled as to what's going on, and I welcome any reader suggestions!