I just installed one the other day and it looks incredible but something weird has started to happen.  When the DMG is first turned on everything looks great but when I hit the Start button to start LSDJ playback the contrast on the screen changes.  When I hit Start again to stop the playback the contrast goes back to normal.  This wouldn't be a problem except when the contrast changes the change is so extreme that I am unable to see anything without adjusting the contrast wheel.  This is extremely annoying when writing, having to repeatedly change the contrast wheel. 

Is this normal?  If not what could I have done wrong?

make sure your batteries are fresh.  there is a greater draw on them with this circuit added (same with adding any circuit really), so it may have taken the batteries you had over the threshold...

that'd be my first guess.  there is no reason this should happen really.   as long as you hooked everything up correctly.  (to the point you can't see anything)

although, its not abnormal at all for this to happen when using LSDJ and starting playback.  not really sure the exact reason for this tbh...  but it does happen.  the extremeness of your contrast change i would think might be batteries.

Is this normal?  If not what could I have done wrong?

I ordered the backlight and got it today. Before I say anything else, I'd just like to say that it is beautiful. Much easier on the eyes than the v3 and I like the blue more (if it's changed at all, maybe I'm just crazy) when it's inverted. Here's a picture:

(The contrast looks much better in person.)

As much as I love it, however, I can't help but wonder if the hum is louder than it should be. I was expecting something similar to the high frquency sound of a CRT television, but it's much louder. I soldered it to the points instructed in the tutorial and my easy clk mod is soldered to the same points. I've uploaded three examples to my soundcloud with lsdj, megaman 3, and the noise from the speaker hole with my webcam.

http://soundcloud.com/thnikk/sets/sound-tests

Luckily, there is no sound in lsdj after the nintendo screen. Megaman 3 (as well as every other game that I've tried) produces the same hum that you can hear on the nintendo screen, if not louder (Metroid 2 got a little bit louder). I recorded the speaker noise because I think that's the most important since I use my dmg primarily for lsdj and the music from any games I play on it make the noise pretty unnoticeable, but that's only with headphones. The sound from the speaker is always there, regardless of volume or the cart, and is very loud. If I went into a library with it, everyone would give me a dirty look... okay, maybe not that loud, but I'd say it's about as loud as 1/2-3/4 volume sounds.

The reason I'm most curious is to know if the sound from the speaker hole is from the speaker itself. I'm tempted to stick some tape in there (or completely remove the speaker) to dampen the noise a bit so people won't look at me funny if I take it outside. I don't really care if the speaker itself is dampened because it's already pretty quiet to begin with, and I use it for the same reasons kineticturtle uses it.

By the way, I am totally loving the easy clk mod. I had a half speed crystal very ghetto-ly soldered to a switch with the original one before, and it's nice to not crash my games anymore.

edit: i should probably mention re: the hum...  i get no hum, no matter what, through one unit.  i just modded another, and get no hum whatsoever in LSDJ until playback starts (audio is engaged) then is goes away when playback stops.  so, i need to figure this out more.  turning off the backlight makes it totally go away.  the other unit though, the one i've been testing all this with...  not a problem at all.  its strange, i haven't done anything different.  so, i'll keep on with this bit.  turning the backlight off with a switch on the power wires would of course make it go away totally though.

hopefully tomorrow.  everything is packed, just need to do tutorial.

edit: Let me clarify; I got confused because Justin's writeup made it seem like 5v from the capacitor under the monitor was the problem, and taking power from where he took it in his photo was the solution. This makes more sense. I actually looked to the four wires coming off the regulator as a possible source, but couldn't remember which was which (and forgot, as I recall now, that they're actually labeled on the regulator board).

In other words, I think once this has a cohesive installation guide, it's gonna be an awesome, awesome product.