# making GB Boy Colour suck less



## romanaOne (Nov 12, 2017)

The fastforward music and slightly too fast gameplay is really not great, esp. with run-and-jump games.
It's impossible to find the original GBC 4.1 MHz crystal but 4MHz is common.

Has anybody ever removed the 5MHz oscillator and replaced it with 4MHz in GB Boy Colour? I've seen videos of  this mod working with "GB Boy" on youtube.  

Well, if nobody has, I'll report the results.


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## romanaOne (Nov 17, 2017)

romanaOne said:


> The fastforward music and slightly too fast gameplay is really not great, esp. with run-and-jump games.
> It's impossible to find the original GBC 4.1 MHz crystal but 4MHz is common.
> 
> Has anybody ever removed the 5MHz oscillator and replaced it with 4MHz in GB Boy Colour? I've seen videos of  this mod working with "GB Boy" on youtube.
> ...




So my 4MHz oscillators came in the the mail.  I took apart the "GB Boy Colour." This GB Boy Colour is the one without the "166"  (really 66 different games, repeated 3x). *There is no 5MHz crystal in the GB Boy Colour. It has a 25MHz crystal*.   Maybe it is some kind of GBC emulator running on a SoC...whatever it is, it's nothing like a real GBC.

In any case, the sound on "GB Boy Colour" is not as terrible as on the GB Boy. While crappier than a real GB(C), the problem isn't that the music is too fast. Nevertheless, there is something not right about it.

I did, however, replace the 5Mhz crystal with 4MHz in my non-colour "GB Boy" and the sound is MUCH BETTER with it running at 4MHz.


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## koffieleut (Nov 17, 2017)

Awesome, nice to see that there are people out there that mods those consoles.


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## Localhorst86 (Nov 18, 2017)

A good mod would be a mod to the power LED that dims when the battery runs low. At the moment, the system dies without any warning that the batteries were low.


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## cybrian (Nov 21, 2017)

Localhorst86 said:


> A good mod would be a mod to the power LED that dims when the battery runs low. At the moment, the system dies without any warning that the batteries were low.


It doesn’t dim like that? That’s kind of funny… that just means the power LED is connected after the voltage regulator, instead of before. If you have the “unregulated” voltage from the battery going directly to the LED (with a current-limiting resistor in series with it so it doesn’t just burn out…) the LED’s brightness will vary with the battery voltage. If it’s _after_ the regulator, then the regular will keep the LED as close to full brightness as it can before the whole thing gives up.

I’d have to take mine apart to know how to solder it up, but the basic thing I have in mind is soldering the LED and its current limiting resistor to the power switch.


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## romanaOne (Nov 22, 2017)

I considered using a single green LED and resistor, but after a bunch of testing I found the brightness did not vary enough over the required voltage range: rebooting flakiness starts at about 2.6V. I pretty much have to use alkaline throwaway batteries or NiZn.

I left the super-annoying power LED alone. Is it safe to remove it?

I did rig up a few 10K resistors with an RGB LED and this works OK across the batteries. Due to the differing forward voltages of the red, green, and blue diodes, the color varies from whitish green to very red as the (NiZn) batteries discharge from 3.6V to 2.6. I measured the current and it is <<1 mA .


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