Does anyone have any idea how to fix the sound output on a Nintendo M82 display? I bought one probably close to a year ago and the seller didn't bother to tell me the sound didn't work, and I'm not smart enough to figure out how to fix it myself On the inside of the unit, there's a little knob that has a slot a flathead screwdrive fits in (a friend of mine who claims to know a thing or two about electronics calls this a "potentiometer"). Turning this turns the volume up. Unfortunately, it can only be turned a little bit before the whole unit just turns off, and the volume is still so low that you have to turn the volume on a TV up all the way just to hear anything (and then there's a lot of buzz in the background). I tried replacing that thing, thinking that might be the problem. Same thing happens. If anyone has any idea of what I should try to get this working, I'd really appreciate the help. This is a picture of the main stuff inside the M82 This is the part on the left that has the volume adjuster. The thing I replaced is circled in red. I'm not sure if these pictures will help, but I'm hoping there's something in there that will just jump out as an obvious problem to someone who knows a bit more about things like this. Thanks!
I don't know how to fix that thing, or what the potentiometer does, but you could try checking (very carefully) if the sound is still working well enough coming from the CPU. Pins 1 and 2 on the CPU -- in your top picture it's one of the largest two chips; pins 1 and 2 are the top-leftmost pins -- output the audio from the NES. You could carefully tap audio from that and see if it works, then follow the circuit from there to see if any components severely limit or cut off the sound.
maybe you should try the nesdev forum: http://nesdev.parodius.com/bbs/ maybe someone there know something
Thank you ccovell and babu for your suggestions, I really appreciate it. I'll see what I can do; I'm not at all familiar enough with the chips in this thing to have known which ones (let alone which pins) contain the audio outputs, and I've never come across the website you mentioned before. Hopefully I can get this thing back to its original glory Thanks again.
The CPU is the labeled 2A03, the "top" of the chip has the notch Code: +--v--+ audio 1 ---| | audio 2 ---| | | | | | | 2A03| ~~~~~~~ ~~~~~~~ | | +-----+
are you 100% sure this is the volume regulator? i dont have a m82, but to me, the brown pcb looks like a plain power supply without any audio amplifying circuitry. might very well be the +5v voltage adjustment for the whole system wich could fry your system if adjusted wrong. all im saying is: unless you know what youre doing, its probably not a good idea to just randomly turn a knob here and there. as a general suggestion, i'd first check for shorts or cold solder joints and loose connections in the audio amplifying circuit. if i was trying to replace something in this system, i'd start with the rf-output box first and work my way through to the cpu.
d4s and Blur2040- Huh. That would probably explain why the thing shuts down when I turn it too much. Obviously I'm pretty far from being even an electronics amateur, let alone expert. The volume got a tiny bit louder when I turned it, so I thought "This must be the volume knob!" Shows you what I know. I'm starting to think that maybe I should just leave this alone before I break it. But before I do that... Kyuusaku- Thank you for the diagram. ccovell had mentioned trying to "tap" the audio from those pins. It didn't occur to me that I don't really know what the means until just now. Should I try to check those pins with a multi meter, or is there something else I should be trying? Other than just leaving it alone so it doesn't get destroyed, of course. That's my next step. Thanks!
Well if you are going to tap the audio from those 2 pins, You'll need to solder a wire to each pin, and connect that to the output instead of the current audio. I don't know if this has standard AV ports or not - if it does then just chop the 2 connected to the audio port (or desolder it from the mainboard) and replace it with the 2 you soldered from the Processor. For reference, Generally mainboards don't have internal volume controls - If they have one they're normally external. Finally, I'm not sure if the audio is processed any more after leaving the CPU - If it does then you will, of course lose this extra processing. However, I am not certain if there is any on the NES - I doubt it but someone else will be able to confirm, and probably correct my mistakes!
The audio is handled a tad, find Kevtris' schematic of the path here: http://www.tripoint.org/kevtris/nes/nespics.html
Cool, thanks again for everyone's help. I'll see if I can do anything without breaking the thing altogether and let you know how it goes
