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Hello! I heard somewhere that some unresponsive buttons are caused by the back pcb. Is there any way to fix this? Thanks!

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Freiburg, Germany

Sometimes a bit of rubbing alcohol can already be enough. I've bought a DMG with a Start button that did not work no matter how hard I pressed. When cleaning it some rubbing alcohol got into the gap between the Start button and the case and when trying again later to my delight it worked. So before you take any other measures try cleaning things.

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matt's mind

this can also be caused (pretty easily in fact) by inserting the LCD PCB's ribbon cable into the back when the power is on. 

but that can be found out from particular buttons not working, but i can't recall what they are off the top of my head.

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I did try cleaning the contacts, when I tested it with another back pcb, it worked perfectly. Any ideas on how to fix it, kitsch?

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matt's mind

if you've shorted out the buttons, there isn't a way to fix this.  its damage in the CPU from what i know, i believe it was nitro2k01 who was talking about this recently on here so maybe he'll chime in...

it sounds like that may just be it, unfortunately.  back PCBs being the common issue, and the front one working fine. 

is the start button the only one you are having issue with?

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Also the left on the dpad I think...

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nitro2k01 wrote:

The power supply is generating a negative voltage, about -19V, for the LCD. The lead on the ribbon cable that carries this voltage, is right next to one of the lines that has to do with reading the joypad. If you disconnect or connect the ribbon cable while the power is on, these two may short and permanently destroy one of the button inputs on the CPU. When this happens, left and B stop working at the same time.

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matt's mind

^ yeah, that bit of nitro2k01 knowledge is just what i meant!

so, left isn't working....  check...

how's the B button?

(even if its fine, i have a hunch this is the issue)

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Freiburg, Germany

So just to be clear, that would only be fixable by replacing the PCB with the CPU on it?

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Sweeeeeeden

If it's the B button and left on the D pad that doesn't work, yeah you're pretty much screwed. This can happen when you insert or remove the the ribbon cable while the unit is on. The reason is that the combined input for the left and B buttons on the ribbon cable is situated next to the LCD power supply, which is nominally -19V. If you short that input to that power supply, (by slightly misaligning the ribbon cable at any point) you immediately fry it.
Edit: Repeating what I was quoted saying, using different words. Fun fun.