VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

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Danexmurder
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VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by Danexmurder » Sun Apr 25, 2021 12:19 pm

Hi, I was planning to convert a Madara board to Akumajo Densetsu and apply the English translation/new Alucard sprite patch. It seems like all I would need to do would be to lift pins 9 and 10 and switch them. When I split the translated file it says the prg and chr roms are 256k. Seems like I should just be able to burn them to a pair of 27C020 roms and replace the originals. I wanted to check in here and see if this would work. Thanks!

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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by lidnariq » Sun Apr 25, 2021 12:25 pm

Should be right.

As far as I know, all 32-pin ROMs not on PCBs made by Jaleco or Nintendo use a pinout compatible with 27xx PROMs, but do double check before you solder things in.

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Danexmurder
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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by Danexmurder » Sun Apr 25, 2021 12:30 pm

lidnariq wrote:
Sun Apr 25, 2021 12:25 pm
Should be right.

As far as I know, all 32-pin ROMs not on PCBs made by Jaleco or Nintendo use a pinout compatible with 27xx PROMs, but do double check before you solder things in.
Awesome, thanks for the fast reply. I tried finding the pinout for the MB83200 roms that the Madara board uses to double check but had trouble turning anything up.

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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by lidnariq » Sun Apr 25, 2021 12:44 pm

Yeah, you'll have to use the continuity tester from the pins on the VRC6 itself.

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rainwarrior
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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by rainwarrior » Sun Apr 25, 2021 3:44 pm

Danexmurder wrote:
Sun Apr 25, 2021 12:19 pm
It seems like all I would need to do would be to lift pins 9 and 10 and switch them.
If you can follow the traces on the board, it might be easier and less damaging to the chip to cut the traces with a knife and reconnect the pins with wires instead of cutting/lifting them.

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Danexmurder
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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by Danexmurder » Mon Apr 26, 2021 8:44 am

rainwarrior wrote:
Sun Apr 25, 2021 3:44 pm
Danexmurder wrote:
Sun Apr 25, 2021 12:19 pm
It seems like all I would need to do would be to lift pins 9 and 10 and switch them.
If you can follow the traces on the board, it might be easier and less damaging to the chip to cut the traces with a knife and reconnect the pins with wires instead of cutting/lifting them.
The way I did it is fully reversible. I just vacuumed out the old solder and bent the pins up through and straightened them out. Then I ran small kynar wire up through the old vias to each new pin. You can't even really see the wires from the top. It can be potentially risky doing it that way though.
Last edited by Danexmurder on Mon Apr 26, 2021 8:55 am, edited 2 times in total.

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Danexmurder
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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by Danexmurder » Mon Apr 26, 2021 8:53 am

I just wanted to report back that this method worked out great! I also used a small low-profile pin converter and put it in a new NES shell. Had to Dremel out a portion to make it all fit but it works great. It's really awesome to play this with the expansion audio in English finally. The new Alucard sprite is pretty cool too!

Image

Image

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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by rainwarrior » Mon Apr 26, 2021 1:06 pm

Danexmurder wrote:
Mon Apr 26, 2021 8:44 am
The way I did it is fully reversible. I just vacuumed out the old solder and bent the pins up through and straightened them out. Then I ran small kynar wire up through the old vias to each new pin. You can't even really see the wires from the top. It can be potentially risky doing it that way though.
Ah, glad it worked out then. I've had a lot of bad luck with pins snapping off in the past, so I think of bending them as a last resort, though some ICs are made with less brittle metal than others.

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Danexmurder
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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by Danexmurder » Mon Apr 26, 2021 2:49 pm

rainwarrior wrote:
Mon Apr 26, 2021 1:06 pm
Danexmurder wrote:
Mon Apr 26, 2021 8:44 am
The way I did it is fully reversible. I just vacuumed out the old solder and bent the pins up through and straightened them out. Then I ran small kynar wire up through the old vias to each new pin. You can't even really see the wires from the top. It can be potentially risky doing it that way though.
Ah, glad it worked out then. I've had a lot of bad luck with pins snapping off in the past, so I think of bending them as a last resort, though some ICs are made with less brittle metal than others.
For sure. I've stopped doing it that way for most of the famicom games that I work on. In general I find it easier to cut the legs at the 90 degree bend and just bend the down. That way if I ever want to reverse it I can just bend them back into contact and resolder. For whatever reason I just wanted to try it that way on this one and it worked out ok.

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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by pakosup » Mon Apr 26, 2021 10:07 pm

32pin 27x is compatible with konami board, but to place Akumajou Densetsu to Madara board you should swap two address for mapper (a0 and a1).

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Danexmurder
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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by Danexmurder » Tue Apr 27, 2021 8:46 am

pakosup wrote:
Mon Apr 26, 2021 10:07 pm
32pin 27x is compatible with konami board, but to place Akumajou Densetsu to Madara board you should swap two address for mapper (a0 and a1).
Yep! Swapped pins 9 and 10 on the VRC6 chip.

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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by 2600 » Tue Apr 27, 2021 12:03 pm

Danexmurder wrote:
Tue Apr 27, 2021 8:46 am
pakosup wrote:
Mon Apr 26, 2021 10:07 pm
32pin 27x is compatible with konami board, but to place Akumajou Densetsu to Madara board you should swap two address for mapper (a0 and a1).
Yep! Swapped pins 9 and 10 on the VRC6 chip.
IIRC, there was a patch posted here so that you didn't need to physically swap pins.

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Danexmurder
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Re: VRC6b conversion to VRC6a - Madara to Akumajo Densetsu question.

Post by Danexmurder » Tue Apr 27, 2021 1:49 pm

2600 wrote:
Tue Apr 27, 2021 12:03 pm
Danexmurder wrote:
Tue Apr 27, 2021 8:46 am
pakosup wrote:
Mon Apr 26, 2021 10:07 pm
32pin 27x is compatible with konami board, but to place Akumajou Densetsu to Madara board you should swap two address for mapper (a0 and a1).
Yep! Swapped pins 9 and 10 on the VRC6 chip.
IIRC, there was a patch posted here so that you didn't need to physically swap pins.
Ah got it.

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