NMS-8280 megaflashrom sound problems

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By Wild_Penguin

Hero (584)

Wild_Penguin's picture

24-01-2020, 21:52

The values of the resistors (and caps) are right there in the firstsecond page (well, the first one has the NMS8245 circuit ... the values should be same). Google translate is your friend with these kind of documents. It wont be perfect but usually close enough there should be no ambiguity. I think this mod has been discussed on this forum, you might want to use the search. I have not seen English documentation anywhere (actually even this Spanish one is a bit difficult to find; it's linked in many places but the links are pointing to a wrong place). I do believe an English translation would be welcome! Cool

However, when doing any H/W mod you should understand what you are doing (maybe not 100% but at least somewhat), not just follow blindly instructions. There can be errors in the instructions - something an electrician will notice since they are trivial for someone who is educated, but someone who has no idea, are not. It is also a lot more easy to make errors if you don't understand the modification. I've learnt this by practice. Wink

I'd look for someone more able near you to make the modification for you or at least help you. If you want to attempt this yourself, and there's still something unclear after using search and Google translate, just ask here. There's a lot of Spanish-speakers here (not me, though) and probably also many who have made this modification. By a quick glance making the mod should be quite straightforward (I didn't go through it thoroughly, though, or use some translator)... looks like the rest (after the schematics on the first page) are just examples how to do this on the NMS8255/50 MB. Yours is 8280 so of course you need to adapt them (assuming the MB is not similar).

EDIT: I actually just skimmed trough it with Google translate. The modification is not identical to the NMS8245 circuit, but mimics it. They've (at Aquijacks) made it more simple so it is easier to make. Google translate does quite a good job with translating from Spanish -> English IMO Smile

By Meits

Scribe (5734)

Meits's picture

24-01-2020, 21:57

Your profile says you're Dutch. This is at least one of the fixes.
Then there's a fix which requires you to solder a capacitor to each of your cartridge slots. One of my Philipses has that fix done. I can check it out for you if the first (very simple) mod didn't fix it completely.

By BiT

Resident (33)

BiT's picture

25-01-2020, 08:00

Thank you Wild_Penguin for your information. I'll try to translate and find out some more. I think you're right about the errors I could end up with. I won't like that

Meits wrote:

Your profile says you're Dutch. This is at least one of the fixes.
Then there's a fix which requires you to solder a capacitor to each of your cartridge slots. One of my Philipses has that fix done. I can check it out for you if the first (very simple) mod didn't fix it completely.

Would be great if this simple mod would fix it, so please let me know if it works for you. I already had contact with Bas for more information. Maybe he can do this for me..

By gdx

Prophet (3217)

gdx's picture

25-01-2020, 10:20

Meits wrote:

Your profile says you're Dutch. This is at least one of the fixes.

The English version: Sound Fix 8250-8280.zip

If it is not enough try the method of which Wild_Penguin speaks. Keep us informed about the result please.

By BiT

Resident (33)

BiT's picture

25-01-2020, 12:38

Thanx for the the link GDX. I think this could help with the internal PSG and a single sound expansion cartridge mixing problem. But probably won't fix the short circuit issue. Or use a FM pac in combination with a MFR or Music Module. The problem is that no other sound expansion will work when the MFR is plugged in.

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