FC twin 50/60hz mod question (+ adding a CIC chip tutorial)

[Random_Hajile1980]

After much poking I may have finally figured out the 50/60hz mod.

NOTE: I have not actually completed this mod yet so keep in mind this is so far untested theory.

it appears the mod is much the same as a SNES 1 chip model. there is a jumper that from factory ties a pin on chip GF-6976 to ground, (it's directly right of the 8bit LED) the alternate setting on this jumper is 5V. it seems that if this pin is changed to hold 5V and the Xtal next to pin 1 of chip GF-6975 is changed to the PAL equivalent Xtal, it puts the system into PAL mode.

I still have to finish testing this finding, and then actually do the mod to see if it actually works (or fries the console :-O )

stay tuned....

[Random_Hajile1980]

I finally bit the bullet and decided to try the 50hz mod on my FC twin. the verdict??

IT WORKS!!!!!!! in fact it's much easier than I thought, it seems only the jumper next to chip GF-6976 needs to be changed to make the system boot into pal mode, changing the crystal to the pal equivalent is unnecessary.

It's almost EXACTLY the same as the retro duo's 50hz mod, and much like the Retro Duo 50 Hz switch, this mod can only output Black and white in 50hz mode. I haven't figured out how to output color (short of a RGB mod that is)

So, there you have it and all told it's easy to do.

now I'm on to a retro duo, anyone ever find a way to fit a lockout chip on that puppy?

[Ace_1]

In order to get the system to output in color, you have to set the CXA1145/CXA1645(depending on which one is in your FC Twin) to PAL mode. Look at the datasheet for whichever encoder you have, and then modify the circuitry around it to display the FC Twin's 50Hz output in color in Composite and S-Video.

By the way:

now I'm on to a retro duo, anyone ever find a way to fit a lockout chip on that puppy?

Being as the RetroDuo and FC Twin basically share almost identical circuitry on the Super NES side, I should be able to trace on the FC Twin board which pins of the lockout chip link up where on the FC Twin's Super NES board.

[Random_Hajile1980]

In order to get the system to output in color, you have to set the CXA1145/CXA1645(depending on which one is in your FC Twin) to PAL mode. Look at the datasheet for whichever encoder you have, and then modify the circuitry around it to display the FC Twin's 50Hz output in color in Composite and S-Video.

By the way:

now I'm on to a retro duo, anyone ever find a way to fit a lockout chip on that puppy?

Being as the RetroDuo and FC Twin basically share almost identical circuitry on the Super NES side, I should be able to trace on the FC Twin board which pins of the lockout chip link up where on the FC Twin's Super NES board.

OK i'll look into the data sheet for the 1145M that i have to see about outputting color.

EDIT: looked at the data sheet, turns out that the first switch I had attempted for the 50/60hz mod was actually for PAL/NTSC color, that's why my TV only output B&W in 60hz when I tried it before, but when paired with a 50hz signal you get full color so I should be able to rig up a dual switch to jump both at the same time :END of EDIT

I decided to finish this system and give it to my brother-in-law since he just loves it and it gives me an excuse to get a Retro, which I've been dying to tinker with.

If we can figure out how to hookup the lockout chip on the RD we should have complete compatibility, What would be even better is if you could rig up a way to switch between the Pal and NTSC CIC chips.

It's really too bad about the Castlevania 3 and Powerpak incompatibilities with the FC twin, it's really a neat machine I wouldn't even bother getting a Retro if I could use those carts on the NES side.

[Ace_1]

If we can figure out how to hookup the lockout chip on the RD we should have complete compatibility, What would be even better is if you could rig up a way to switch between the Pal and NTSC CIC chips.

It's really too bad about the Castlevania 3 and Powerpak incompatibilities with the FC twin, it's really a neat machine I wouldn't even bother getting a Retro if I could use those carts on the NES side.

If you can wait, Yobo is releasing on the 22nd the FC3, a 3-in-1 system combining an NES(with proper Castlevania III compatibility), a Super NES and a Genesis.

As for CIC chips, I believe if you piggy-back a PAL and NTSC lockout chip, and rig a switch between pin 4 of the chips, you should be able to restrict use of either PAL or NTSC carts.

[Random_Hajile1980]

OK then so it looks like finding the Retro Duos' Lockout chip pins should allow a 100% SNES compatible machine.

The FC3 you mentioned sounds pretty cool, the only thing I wonder is will it have some weird one-off-controllers like the GN twin that are incompatible with anything else. I'll wait and see how it looks before I buy since info online is pretty scarce as of right now, but the Retro is probably the way I'm gonna go.

[Shinryu]

I finally bit the bullet and decided to try the 50hz mod on my FC twin. the verdict??

IT WORKS!!!!!!! in fact it's much easier than I thought, it seems only the jumper next to chip GF-6976 needs to be changed to make the system boot into pal mode, changing the crystal to the pal equivalent is unnecessary.

It's almost EXACTLY the same as the retro duo's 50hz mod, and much like the Retro Duo 50 Hz switch, this mod can only output Black and white in 50hz mode. I haven't figured out how to output color (short of a RGB mod that is)

So, there you have it and all told it's easy to do.

now I'm on to a retro duo, anyone ever find a way to fit a lockout chip on that puppy?

Yeah !,
It's a very good News .
Can you give me some pictures and plz a tutorial for all people who want to make this

[Shinryu]

T WORKS!!!!!!! in fact it's much easier than I thought, it seems only the jumper next to chip GF-6976 needs to be changed to make the system boot into pal mode, changing the crystal to the pal equivalent is unnecessary.

Hi,
I just opened my fc-twin for add the 50hz mods with your method but i don't find the jumper.

so this is the picture of my fc twin ( model FCX2):

[Shinryu]

sry but anyone can help me for find the jumper?

[Gatchan]

Stop bumping the thread. It's christmas holidays, so people are busy doing other stuffs...
On the RetroDuo, the main part of the switch is connected to these two pins on the TCT-976


So, either you find a via for these pins on the pcb, or you connect a wire to these points, then either to +5v or GND.
I didn't test them, as I don't own a FC-Twin, so be careful.

[Pullmyfinger]

Hello everyone, sorry for reviving such an old thread, but it seemed better than opening a new one.

Anyways, I would like to know if the PAL/NTSC modding worked out or not, I just bought an FC Twin at a flea market in southern CA, it had no box, cables or controllers, so I used SNES controllers and a Genesis model 1 AC adapter to power it on, NES games worked out fine, but all SNES games had the video coming out in pal and some others like Megaman X and Donkey Kong Country gave error screens (also in PAL). The system has a sticker underneath that says it's NTSC, I opened up and I couldn't find wires, solder or any signs that it had been modded. I would like to know if this mod ever worked out (with full color) and if my FC Twin could be of any help at all.

[Random_Hajile1980]

Wow! lots of stuff went down during my absence.
I haven't been online in months so I'm sorry if you were waiting on pins and needles for info about this.

Update related to my twin:

shortly after going offline from benheck.com, my FC twin's NES side failed, I never was able to find out why.
The Lockout chip I fitted to the SNES portion still works to this day, as does the 50/60 hz switch according to my brother in law who got the system from me.
his current TV does not display color in 50hz mode however, and I think this is the TV's fault not the system.

Update related to photos to go with the tutorial I wrote before:

I have a poor quality digital camera, which would not be able to take a clear enough photo to do much good, I tried several times, I am also at a loss where I would host the pics when I get a nicer camera, and I no longer have direct access to the system.
So I have to leave photos to those modders with better cameras


Shinryu: it appears you have a different motherboard revision than I, the version of SNES board I have can be seen in this thread:

http://forums.benheck.com/viewtopic.php?f=3&t=16960" onclick="window.open(this.href);return false;

It is unfortunate that there are 2 versions that differ so much, but I am sure your version can still be modded, although I am unsure how to go about modding your specific board, and it will likely be more work since the jumpers may not be present.


A few thoughts:
I have personally given up on the FC twin as a viable all-in-one system due to the poor NES compatibility, don't get me wrong! it still makes a great portable though, and I intend to one day get another to hack into a portable SNES, but for my main-home-system I went back to my real SNES and bought a used super 8 converter, I can play all my games including castlevania 3 on it without issues, something I couldn't do with my twin.
it's much easier to mod a real SNES in this case because the lockout chip is already there, and the 50/60hz mod is well documented and easy to do.

at any rate, I wish you all good luck with your mods, I don't post often but will be reading to see how you fare.

[themadhacker]

so wait, you added a lockout chip to the snes side? mario rpg requires a lockout chip to run, so is it compatable now?

[Random_Hajile1980]

yeah mario rpg runs just fine. it also runs kirby superstar without a hitch.
I detailed how to add the cic to the twin (much) earlier in the thread.

the only thing i see as a problem is there seems to be another version of the FC twin snes board which lacks the place for the cic (lockout chip) the version I had and hacked successfully was an early non-yobo model.
probably when yobo made revisions to improve colors and sound, they dropped the place for the lockout chip and the pal jumpers.

these systems will be much harder to mod for compatibility, i doubt it will be impossible, but it's up to the modder to decide if it's worth it to perform the fix or not.

[themadhacker]

if you can, can you post a pic of everything wired together? This proves very useful to me, as I am making an fc twin portable, and would like to play mario rpg.