Hi there,

I'm still fairly new to modding, and I've noticed my Game Boy (CPU-06) is overheating in the left-hand corner. I've got a 100 ohm resistor on its backlight, but I've heard that replacing the regulator may be a good idea.

I was looking at this one: … &psc=1

Is there a diagram or tutorial I can follow to set this up? I've never done anything like this before. Do I desolder the old regulator and replace it, or does the new one run in parallel?

Any help here would be greatly appreciated.


You do not want to replace the regulator in this instance, you just want to bypass it. You will want to connect this to the non-regulated power source after the power switch.

Honestly, you could just connect the backlight directly to this source with the 100 ohm resistor and skip the regulator completely. This means the backlight will vary in brightness, but you will probably never notice it.


So if I were to install the new step-up/step-down regulator anyway, it'd hook up to the non-regulated power source after the power switch? I may want to try that, as I play in a lot of dark rooms and a solid screen consistency would be nice.

I found this old thread that seems pretty helpful: … rduinoboy/

Is there a good visual aid for  where the non-regulated power source  is located? Up until now I've done speaker replacement, prosound, and biverting, but I'm still learning how it all works on an electrical level.

Sea of Souls

The battery contact itself should be fine for an unregulated source, but like Apeshit said, you can't just 'replace' the original regulator. It produces both +5v AND -21. The LCD needs this to function so you'll need to keep it in there.


That makes sense. I was mostly going off of this thread: … ck/page/2/

Someone mentioned that tapping power from the battery contacts would mean the backlight won't turn off when you power off the system. There was also the suggestion of using an extra power regulator board (5v step up/step down from Pololu) in connection with the unregulated power to keep the voltage to the backlight steady.

To me, that sounds ideal. I just want to understand where the best spot for unregulated power would be and what the process is before I solder anything. Like if I use those connections to the power board that Irony7 mentioned for unregulated power, how would the extra regulator board be connected in conjunction with the backlight?

Last edited by HoneyWizard (Nov 18, 2018 2:31 am)


Hey, just wanted everyone to know I solved my problem! I found a spare-parts CPU-08 revision Game Boy in a drawer. Since that one doesn't have regulator issues, I can keep the LCD board from my previous Game Boy but swap the logic boards.

In the future, I guess I can buy busted-up Game Boys and swap the boards out this way, or maybe it's possible to swap out just the OG regulator with a newer-revision OG regulator. Just in case I get a board with a ton of issues but the regulator's fine.

I also found a forum and video on a good unregulated power source. Just like Apeshit said, it'll dim the backlight as the batteries drain, but I believe it's connected in a way where the backlight will shut off with the power switch.

Forum post: … post309996

Video: … 0sHbYRC4ow

Don't need to do this at the moment, but still good to know.

Last edited by HoneyWizard (Nov 20, 2018 5:32 am)

Sea of Souls

Yeah, the CPU-08 is excellent and does have a newer revision power regulator board.


The CPU-08 has a different newer regulator, but it isn't free of issues like this.

You should really consider connecting the backlight to the unregulated source. The thread you linked shows the source you can connect to post-power switch.

While it will technically dim, I reiterate, you probably won't notice it. It was standard practice for years to connect backlights like this in DMGs.


Ah, that's a shame. Thought swapping the boards would be an easy fix.

So if I use the unregulated source, the positive wire goes to the unregulated power from that thread. For the negative wire, though, is the spot at 0:11 in the video a good place for it?

Also, thanks for saving me from "fixing" a Game Boy only to have the same problem. I really appreciate it.

Last edited by HoneyWizard (Nov 21, 2018 11:05 pm)