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ChipMusic.org / Forums / Nintendo Handhelds / Have we figured out what causes noisy sample playback on some DMGs?
This has been an inherent issue ever since I got into modding. Replacing the rear PCB fixes it. It's isolated to WAV channel sample playback. Any of you who've heard it know exactly what I'm talking about. Samples have a noisy "whine" to them 100% of the time.
Any hypothesis on what causes this issue, and how to fix it?
Its a bug on dmg-02 rev mobos isnt it? Luckily you can see the number through the battery hole.
Examples comparing a noisy signal to a "clean" one?
This was addressed in my thread about DMG CPUs awhile back.
Im getting that noise when I try to play samples in a CPU-04, that is supposed to be working, even if I MUTE every channel, when the pointer gets to the part that should play the samples, I get that noise 
If you have a motherboard that does this, feel free to send it to me for analysis.
Actually, I realize I have a really old (and dirty) DMG that I bought cheaply on an auction for its low serial number, and it has this problem. Unfortunately, after a quick analysis, I don't think the particular problem is related to bad/low value capacitors, but how the sound circuit in the CPU chip is constructed. It seems like when you turn the wave channel off, (which has to be done to reload the sample buffer) it returns to a DC level way outside of the amplitude range of the wave channel. My antispike fix isn't of much help either. Unfortunately, I don't think the problem is fixable. I will try some things, but don't keep your hope up.
Actually, I realize I have a really old (and dirty) DMG that I bought cheaply on an auction for its low serial number, and it has this problem. Unfortunately, after a quick analysis, I don't think the particular problem is related to bad/low value capacitors, but how the sound circuit in the CPU chip is constructed. It seems like when you turn the wave channel off, (which has to be done to reload the sample buffer) it returns to a DC level way outside of the amplitude range of the wave channel. My antispike fix isn't of much help either. Unfortunately, I don't think the problem is fixable. I will try some things, but don't keep your hope up.
Oh, wow. So each time you play a sample your DMG turns OFF a channel? Does that cause...clicking?
On the topic of power spikes, Nitro. Why does a DMG have that audible "pop" when you turn it on? Why do you get the same when you pan L or R? Are they related, or separate causes? Can that L R pan pop be reduced somehow?