Gameboy DMG Overheating After Backlight (Page 1 of 2)

That board is the voltage converter and that component is a transformer. If it overheats, it's either overloaded by what you have connected to it, or there's a short circuit somewhere. Some heat is to be expected, however. Try disconnecting the backlight and see if it stops the transformer from overheating. You may want to review the connection of the backlight. For some models of backlight, you need to connect a resistor of some value in series with the backlight panel. If this resistor is missing, this problem might happen. Edit: The transformer might have internals shorts from previous heat exposure as well.

And a general tip while we're at it. Never connect or disconnect the ribbon cable connecting the CPU board and the LCD board while powered on. This may short two pins, causing the connection for the left and B button on the CPU to be permanently destroyed so those buttons stop working.

Last edited by nitro2k01 (Feb 12, 2014 2:55 am)

The green stuff is glue, don't worry about that.
as for the destruction, he meant that the Left and B button associated to a pin on the CPU could become shorted with the LCD voltage pin, VEE, which is -19v! You asked if "only the back circuit board is destroyed," but it is actually the CPU that becomes destroyed. All other components should remain usable. The front board should be fine.

You said "with batteries in" but was it powered on? Only if it is powered on would there be damage, more likely.
Were you having problems with the buttons?

It is mostly present on all gameboy transformers, by the manufacturer of the part. Some have more than others, some just have a fine film-like substance.

Heat can always damage something, but many parts are rated up to very high temperatures. What kind of heat are you getting? Like, really really hot?

What you need to do is check every inch of both boards. From voltage regulator, to CPU, preamp and even underneath the LCD. If you are lucky, one of your pins is bridged and not actually damaged. P11 is the CPU pin associated with B and Left. If this pin becomes bridges to ground, it will never trigger a press in software. Again, you need to check everything. Solder can crackle and pop and little bits could fly onto your board and bridge pins. Look for particles and debris.

When I fixed some buttons once, it was because of corrosion on the front PCB. The corrosion was nearly invisible, and looked like a tiny shadow on the trace. I checked both sides with a multimeter and found that there was no continuity. I repaired the trace and all was good. Again, if you're lucky.

Last edited by Jazzmarazz (Feb 12, 2014 4:21 am)

Wow, you were correct about that green stuff... Mine looks exactly like the one in your picture.

It's not getting super hot... but hot enough to realize there's a problem.

When you talk about checking the boards for a bridged pin, do you mean as a solution to the left and B buttons not working AND as a solution to the overheating?

I'm worried that the V5 nonelectronic backlight is the reason for my overheating. It is supposed to have a resistor installed but I don't know.

Wow! Nonfinite themselves! ^^

I purchased a crimson v5 backlight, a magenta one, and two bright white ones.

The overheating is not the transformer, as I tried a different back and it also overheated. ( I feel stupid for making a big deal out of it now...)

I soldered it to the places right under the LCD screen.

Would installing a resistor or soldering it to a different place solve my problem? I really want to start putting the magenta one in another DMG...

Shit... That's depressing to hear but I'm glad to know it's not just my DMG before I blindly installed more into other DMGs.

It would be nice if they sold those trim pots separately for the people that already bought V5s... 

Would installing a 100 ohm 1/4 watt resistor to the colored wire be the way to go?

It depends on the color?? I tried searching for info online about installing a resistor but found nothing on the subject.

I appreciate your generosity! But I can probably find em somewhere...

If you install a 33 ohm resistor in your overheating backlights please let me know if it works! I seriously doubt we're the only ones with this problem but I have seen very few threads about it.