diablonet
Posts: 11
Joined: 02 Nov 2018, 16:31

Sega Nomad - CD mod required for Mega SD

17 Jun 2019, 20:00

Hello, can someone please share how to mod the Sega Nomad for Mega SD audio compatibility? thank you

diablonet
Posts: 11
Joined: 02 Nov 2018, 16:31

Re: Sega Nomad - CD mod required for Mega SD

18 Jun 2019, 23:13

I got this from Mobius Strip Tech:

There are 2 methods to modify Sega Nomad to get audio from CD games on Mega SD.

The hard method (better quality), using a triple bypass mod, he will sell the mod on his store on the near future.
The easy method (decent quality), by doing the following mod:

B3->47kohm resistor->0.022uf cap one leg to ground->lift pin 10 of 315-5684 and connect to the non-grounded leg of cap.
Same connection for B1 to pin 24 of 315-5684.


I hope to get a diagram or pics for the easy method.

diablonet
Posts: 11
Joined: 02 Nov 2018, 16:31

Re: Sega Nomad - CD mod required for Mega SD

18 Jun 2019, 23:41

On my research I found that the easy mod method audio sample is 8 bit 22k, this is an audio sample of that quality


diablonet
Posts: 11
Joined: 02 Nov 2018, 16:31

Re: Sega Nomad - CD mod required for Mega SD

20 Jun 2019, 01:41

I did the mod on my Nomad and it works! by this I got the following features:


1.- SMS FM music from Everdrive X7.
2.- WAV playback from Everdrive X7 (22khz 8 bit), sounds acceptable.
3.- Music from Sega CD games running on Mega SD.

I did the following:

B1 (catridge) <-----> .022uf capacitor not grounded leg <-----> 47k resistor <-----> Pin 24 Sega IC 315-5684
B3 (catridge) <-----> .022uf capacitor not grounded leg <-----> 47k resistor <-----> Pin 10 Sega IC 315-5684

I attached some pictures of the procedure:
Image
Image
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Image

capereon
Posts: 1
Joined: 11 Feb 2019, 08:00

Re: Sega Nomad - CD mod required for Mega SD

28 Aug 2019, 01:22

Trying to get this mod working, but I'm not getting *any* audio from the AV jack (tested with both a normal AV cable and then a SCART cable). I do get audio from the headphone jack.

Anything look obviously wrong?

Image

Image

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Todd
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Re: Sega Nomad - CD mod required for Mega SD

28 Aug 2019, 05:23

Thread moved to MegaSD Tech Support.

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Mobiusstriptech
Posts: 231
Joined: 13 Apr 2018, 15:41

Re: Sega Nomad - CD mod required for Mega SD

28 Aug 2019, 06:41

I will take a look at a few things but this doesn't make much sense because the connections being made are simply the same line connections that would exist in say a Genesis/MegaDrive 1 or 2.

This issue definitely will not exist in the triple bypass, which will now be the easier mod of the 2. I just need to finish the balancing of the channels. Which is only waiting on the final prototypes to arrive.

chrisw80
Posts: 22
Joined: 06 Aug 2019, 21:27

Re: Sega Nomad - CD mod required for Mega SD

28 Aug 2019, 17:17

Mobiusstriptech wrote:
28 Aug 2019, 06:41
I will take a look at a few things but this doesn't make much sense because the connections being made are simply the same line connections that would exist in say a Genesis/MegaDrive 1 or 2.

This issue definitely will not exist in the triple bypass, which will now be the easier mod of the 2. I just need to finish the balancing of the channels. Which is only waiting on the final prototypes to arrive.
Is there anyone located in the US that does this mod? Or the triple bypass for the Nomad? Would love to play Sega CD games on my Nomad.

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Mobiusstriptech
Posts: 231
Joined: 13 Apr 2018, 15:41

Re: Sega Nomad - CD mod required for Mega SD

28 Aug 2019, 17:53

chrisw80 wrote:
28 Aug 2019, 17:17
Mobiusstriptech wrote:
28 Aug 2019, 06:41
I will take a look at a few things but this doesn't make much sense because the connections being made are simply the same line connections that would exist in say a Genesis/MegaDrive 1 or 2.

This issue definitely will not exist in the triple bypass, which will now be the easier mod of the 2. I just need to finish the balancing of the channels. Which is only waiting on the final prototypes to arrive.
Is there anyone located in the US that does this mod? Or the triple bypass for the Nomad? Would love to play Sega CD games on my Nomad.
I am in the US. I am the creator of the Nomad Triple Bypass. Currently it is not yet available for purchase or install but it will be. I can do the "simple" mod as well but I will honestly recommend just waiting.

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