ToToTEK.COM

[Tomy]

Hi rbudrick,

You ask for FDS modchip long time ago. I just finished the simple version.
I think everyone can install it.
You need very thin wires to install it. And because no space under FDS pcb board.
You need to put modchip outside of the PCB. (use something to cover it, don't short circuit)
And don't use too long wires. Use as short as possible.
Email me if you need it.

[ChimyFolkButter]

Tomy,

What kind of chip is this? How much and when can I get one?

[kyuusaku]

I assume it's a GAL16V8 which preforms the function of the flip flop and glue.

[rbudrick]

Hi Tomy,

I didn't realize you were making a single mod chip...I thought it was a mod board like the fds copy tool translation I did. By the way, did you get a copy of that?

So, does this replace the 3206, or does the 3206 stay in there too?

Do I have to cut any traces like on the copy tool?

Thanks for following up!

-Rob

[ChimyFolkButter]

I saw a similar solution on NESWORLD board. Someone posted a "modchip" and took a picture of it. It was a GAL16V8. IN addition to the chip, there was also Transistors in the mix with resistors. So, that tell me that their may indeed be the need for extra hardware so to speak. IN addition, cutting the traces to the write heads on the FDS.




However, if Tomy requires the 3206 to be removed and replaced with this...but nah, you need really small wires.

Well instead of me speculating I will wait for the Tomy to clarify.

-CFB

[kyuusaku]

I'm certain it's not a replacement and I'm also certain it's not a single chip since the process requires passives. Look here: http://www.tototek.com/tomyweb/imges/3206.jpg

The same logic can be accomplished without a PLD too--using only discretes like Copy-tool.

[ChimyFolkButter]

Yea, I just ordered my parts and I am going to build the FDSCopy using the flip/flop, logic gates, txnsistors. This is my last effort to try and get FDSLoader to actually write disks.

[rbudrick]

[ChimyFolkButter]

Rob,

The parts are actually available but I had scour the world for them. Some are on ebay and some from digikey.

-Al

[kyuusaku]

You don't actually need those transistors, just need two general purpose NPN and one PNP. You can avoid the transistors altogether if you don't care to do the protection circuit which looks like overkill to me.

[rbudrick]

My understanding is that an earlier version of that doc was published in a previous Backup Technique or Famicom Kaizou Manual article, but there were some complaints regarding the protection that were amended in the translated doc. That was their final version of the FDS mod board.

-Rob

[ChimyFolkButter]

Damn, I should have done my homeowrk on the subsititutes for the Transistors. Anyway, I don't think the protection is overkill, the 74LSXX TTL ICs can sink only sink 20ua. I am sure there could be conditions where the upper limit of the the sink current could be exceeded.

Brad Taylor's subsititute circuit is utilizing a a 7445 address decoder with open collector outputs. He even recommends protection(transistors) for sink and source if the standard logic ICs are used.

Anyway, how would I go about calculating the pull-up resistor values for the protection circuit? I would use the standard NPN 3904 and PNP 3906.

-CFB

[kyuusaku]

I'm at school right now (no Copy Tool) but I'd guess you'd scale it to the new hFE. I don't really think it matters since it's just switching, just make sure you saturate it.

[rbudrick]