[Wear-Hard] $20 320x240 B&W NTSC^H^H^H^H PAL HMD

[orphrey at gmail.com]

> I have been having a problem with this unit where it looks like the
> screen is offset horizontally about 1/7th of the screen height. This
> doesn't happen when it is plugged into the car remote.
>
> I'm going to pull the part, replace it with 220k, and see if that
> clears up the offset.

It doesn't, and the SMD soldering is tricky.  However, I have fixed
the vertical offset problem. I misspoke earlier when I called it a
horizontal offset.

They symptom is that the top 1/7th or so of the display appears at the
bottom of the screen. It looks like the screen was slid up, and
wrapped around to the bottom.

The cause is that the PAL_MODE line of the display driver circuit is
pulled high, putting the chip in PAL mode. Conveniently, there are a
set of pads right near the pullup resistor that can connect the
PAL_MODE line to ground, putting the chip in NTSC mode. If you
desolder the pullup resistor and move it to the other set of pads, the
vertical offset goes away.

This image explains the modification:
http://www.aculei.net/~ams/images/convert_to_NTSC.JPG

Beware, the image is 1024x768.

Also, I'm dismayed to note that wildplanet has started using far more
glue to hold the case lid on the eyepieces. The one that came with my
car pried apart fairly easily. The newer ones do not.