- Thread starter goguelnikov
- Start date
xodaraP
Legendary
I got one to work, but those big flat chips just really didn’t like me. I kept several of them as spares in case I did ever attempt it again, but bought a DS cart
Understood.
Ideally these would be manufactured as castellated holes, but too much $$. so they are going to be milled in half when the edge cuts are done.
Agree that the diameter of the hole does not matter for this use case.
Yield might be a bit low, I’d be inspecting carefully.
TL;DR sounds like this is your best manufacturing option, If it was me I’d do it! (And don’t forget the board thickness)
I know shipping is awful, but happy to do them for you. Only thing I'd worry about is that since we'd have different game lists that I can't actually test them.
xodaraP
Legendary
All good, thank you for the offer but for me it was a failed experiment and I’ve got the DS cart now
davidmorom
Student
Finally completed the mod today, and started to test it. Everything is totally perfect, except for the sound. It is fine about 99.9% of the time, but occasionally there are slightly distorted samples or notes. This is mostly noticeable on the music of the Metal Slug series, there are some notes sometimes missing, sometimes louder than they should. It is not game-breaking at all, but a bit annoying.
This doesn't happen with my other unmodified 161-in-1, and I'm pretty sure (but not 100%) it didn't happen on this one prior modification, so the MVS board is OK.
@rewrite, @ack, @Vortex, or anyone who already did the mod, did you experience something similar? Tomorrow I'll test the mod described by Vortex to raise the regulator voltage to 3.58v to see if it helps. This mod should be done on the PROG or CHA board? I would expect it to be done on the PROG board, as it contains the V ROMs, but on page 14 of this thread Vortex shows the mod on the CHA board.
Did anyone have luck with the voltage regulator mod?
Thanks everybody.
This doesn't happen with my other unmodified 161-in-1, and I'm pretty sure (but not 100%) it didn't happen on this one prior modification, so the MVS board is OK.
@rewrite, @ack, @Vortex, or anyone who already did the mod, did you experience something similar? Tomorrow I'll test the mod described by Vortex to raise the regulator voltage to 3.58v to see if it helps. This mod should be done on the PROG or CHA board? I would expect it to be done on the PROG board, as it contains the V ROMs, but on page 14 of this thread Vortex shows the mod on the CHA board.
Did anyone have luck with the voltage regulator mod?
Thanks everybody.
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Two carts came back to me for randomly getting louder, and it happened largely on Strikers 1945+. I ended up replacing the voltage regulator with one off of a parts board, and reflowed both the V rom Vcc/GND pins and the Vcc/GND socket pins. There's still a single note in Eightman that's louder than the rest (can find it on stage 2-2), but otherwise it solved everything so far. Played about an hour without it changing volume again where it would do it every 5-6 minutes before.
I did try the voltage regulator mod on one of the boards early on, but it didn't make any difference (but the cart didn't have sound issues to start). I tried it on both boards just in case. I think if the voltage regulator is good, it's fine, but sometimes they're a little dodgy (and they're ALWAYS under-soldered, be sure and reflow all 3-4 pins).
You can attempt to make the holes smaller, but every manufacture I looked at had different requirements for castellated holes then normal through holes. Usually with castellated holes they will have a minimum hole size of 0.6mm and distance between holes of 0.6mm. The only way to get them to make the boards has been to not ask for castellated holes and just let the normal edge cut cut them. This is talked about in the docs
https://github.com/jwestfall69/neogeo-161in1-dual-daughterboard?tab=readme-ov-file#pcb-manufacturing
Yes, thank you, I agreed to reduce the size of the holes if the distance between their centers remains the same. With castellated holes, they immediately refused me.
5 double daughter boards cost me $35, for another 10 they asked for only 2 additional dollars, so I ordered 15 - can I use the extra double daughter boards as single ones, for one chip?
5 double daughter boards cost me $35, for another 10 they asked for only 2 additional dollars, so I ordered 15 - can I use the extra double daughter boards as single ones, for one chip?
It should work to use the double with a single chip, but I'm not sure if the extended length of the board might interfere with other parts in the cart.
davidmorom
Student
Finally, I got the audio issues resolved!! I still have to extensively test it, but I think I now have a 100% working cart. I tried a lot of things to fix the audio:
I still have to test it thoroughly, cause maybe I fixed some games and broken others, but till now it seems promising. Metal Slug 2 and Strikers 1945, that were severely affected, now sound fine. Thanks @rewrite for the Strikers 1945 tip, it is a nice game to test, extremely affected by the issue.
Next week, after I tested it deeply, I would like to post some conclusions, advices and photos of the process, I hope it can help anyone that is doing the mod currently, or thinking if doing it or not.
- Checked and rechecked soldering and continuity, specially on V ROM
- Remove the voltage regulators and power the cart boards directly with my test bench power supply, at 3.58v
- Used the test bench power supply, at 5v, to power the whole MVS board
- Increased the value of the decoupling capacitors of the PCM CPLD and V ROM
- Changed the CLPD fitting strategy from Area to Balanced and Speed (removing some games from the include files to be able to compile at Speed)
I still have to test it thoroughly, cause maybe I fixed some games and broken others, but till now it seems promising. Metal Slug 2 and Strikers 1945, that were severely affected, now sound fine. Thanks @rewrite for the Strikers 1945 tip, it is a nice game to test, extremely affected by the issue.
Next week, after I tested it deeply, I would like to post some conclusions, advices and photos of the process, I hope it can help anyone that is doing the mod currently, or thinking if doing it or not.
Guess I'll be ordering some 100pF capacitors! Nice find @davidmorom !!
davidmorom
Student
If you still have some boards with this sound issue, would be nice if you can test it, just to confirm.
I still have one of the two that came back on hand, I'll double check with the owner, but I'm sure he'll be happy to have a definitive fix.
Those capacitors have been there forever. They are 47pF caps; a fix GadgetUK came up with years ago and the Chinese have been installing them ever since. I doubt the issue is wrong capacitor value, the issue is more due to cheap unknown brand. This is why I replace all the caps on PCBs I sell with brand name caps.
In the case of these caps, I use X7R rated caps made by Samsung Electro-Mechanics - $0.02 per capacitor from Digi-key.
davidmorom
Student
To be honest, I just put two lentil shaped trough hole capacitors I had on my component box, that probably are older than me 
. Next monday I will measure the value of the original capacitors, the multimeter I have at home can't measure less than 1nF.
As long as it works, I'm not touching it anymore, but is good to know this is not an isolated issue.
I suspect there must be some timing issues between the PCM CPLD and the YM2610, and some combinations of cart and MVS board may require some fine tuning.
. Next monday I will measure the value of the original capacitors, the multimeter I have at home can't measure less than 1nF.As long as it works, I'm not touching it anymore, but is good to know this is not an isolated issue.
I suspect there must be some timing issues between the PCM CPLD and the YM2610, and some combinations of cart and MVS board may require some fine tuning.
So what's the deal with these ones? I know in @Vortex 's repo there are pics of a cart with this style daughterboard. Are these effectively the same, just visually different, or altogether not usable? (clearly need a different daughterboard PCB). I'd have assumed not usable, but the pics in the repo have me second guessing.
davidmorom
Student
If the connections between the ROMs, the CPLDs and the board edge are the same, they should be usable. Otherwise you will have to do some reverse engineering to figure out how the signals are connected, and modify the CPLDs code in consequence. Regarding the dumping and flashing, on Vortex repo there is a gerber file called "VTXCart_CV_STILT.zip", that I assume is just for this type of daughterboard. And even if everything goes well, I suppose you will have to design your own double daughterboard, or figure out another way to add the third C chip.
