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JohnRambo'sKnife

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Has anyone tried Donpachi on their HAS?

I run a aux cable out to a pair of Insignia powered bookshelf speakers. Issue is the sound effects are fine but the music is heavily distorted and low in volume.

Tried board on a test bench setup and everything sounded fine. Scratching my head.
 
I wonder if one of your OKIs has gone bad, and could be behaving on the test bench JAMMA setup if the 5V supply is subtly different. I don't recall if DonPachi has a little 7805 for the sound hardware or not.
 
Hi Mike,

I replaced both as the board was originally sold to me with sound issues. Replaced Amp, op amp and all e caps. Only the DAC is original now. Could my replacement Okis be crap because they were sourced from Ali?
 

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The replacement OKIs are known for having various issues, though usually that's what we end up removing rather than installing.

Unfortunately, the only way I know to source OKIs is to take them off of dead PCBs, or find a clone that is confirmed to be in cooperating condition.

As for DAC... I'm not sure which DAC you mean. Doesn't the OKI output analogue audio?

One other unfortunate possibility is that the NMK sound banking hardware is defective. That is used to bankswitch the OKI ROMs, and surely that is used for the music. However, I don't see how that would have sensitivity to the type of setup being used, unless a minor voltage supply difference is present.
 
Hi Mike, thanks. By DAC I meant the NMK chip. I thought this was a 1 for 1 replacement with a Yamaha YMZ280B-F?

At my limit with this board. Might just sell it on.
 
Nope, it's not a DAC at all - it banks the OKIs' ROMs on a per-channel basis to increase the effective storage of the ADPCM playback.

If you're frustrated with it, I might be interested in it in its current state.
 
Hi Mike,

Are you certain the Yamaha chip is not a valid replacement? It appears the same chip was used in place of the NMK on Dangun. I want to ideally keep the board. If you are local, would you be interested in attempting to repair it?
 
No, they aren't even remotely similar. Dangun uses the YMZ280 for ADPCM playback. DonPachi has a shitty budget sound section that only has two OKIs for ADPCM playback, and the NMK IC is responsible for banking the OKI ROMs.

I live in San Jose, and could probably take a look at the board.
 
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