Alternate Power Supply and Clocks.

Previously I posted my solution for placing a switch easily without much modification to a gameboy that allowed selection of 2 clock speeds.

But what if you wanted 3 clock speeds, to allow overclocking as well?
This is exactly what Celsius(chiptuner and part of dPad) is looking to do.

The only problem is, the 2.09MHZ crystals, as well as the 8.38MHZ crystals are both extremely hard to source, and when the can be found, are only available in very large sizes, leading to difficulty of placing the crystal within the case.

(image property of deepearthvoid http://8bitcollective.com/images/Deepearthvoid/Underclocked+DMG+mod/)

With so much trouble fitting in one clock, how would you go about fitting not 2, but 3 in there?(although let it be said that the original clock is quite small.)

There are two solutions discussed so far.

The first is to alter the battery compartment of the dmg.
By changing over to a 9 volt battery, instead of 4x1.5v batteries, the space taken up by batteries is halved.
There has been some discussion of alternate voltages running a gameboy including this blog
http://gameboygenius.8bitcollective.com/wordpress/2009/07/22/testing-gameboy-input-voltage-ranges/
and a decent part of this thread
http://8bitcollective.com/forums/viewtopic.php?id=13389&p=3

The general consensus seems to be that there will be no damage to a gameboy in using 9v instead of 6v,(although on gameboy genius it is suggested lcd damage may occur from extreme settings after extended use) but battery life may decrease, as a single 9v battery appears to have a decresed MAh rating, compated to the four 1.5v batteries.

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The second option is to replace all clocks, with more "generic" speeds.
2mhz, 4mhz, 8mhz

These clock speeds are more readily available, and also can be found in smaller sizes.
The downside of this option is that while intune with themselves, this gameboy is no longer in tune with standard tunings.
However, this can be fixed by using a method addressed by little-scale in this posting (http://little-scale.blogspot.com/2009/07/retuning-underclocked-game-boy.html)
The method involves re-writing pitch tables in the LSDJ rom, so that pitches are produced correctly with the new clock speed.
It is suggested for use with 2mhz clock speed, but with the extra clocks running at powers of 2 to this, the pitches will remain in tune for 2, 4 and 8mhz speeds.