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PostPosted: Thu Aug 30, 2012 10:33 am 
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Thx

I noticed that I have a NES-CPU-10 mainboard, and you suggest to remove some caps and resistors.

Do I really have to do it ?


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PostPosted: Thu Aug 30, 2012 10:49 am 
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Isn't it safer/easier/simpler to replace it with a chip from a game cartridge?

After desoldering it from a game PCB, it'd be easy to work with and disable or bend out the correct pin without wrecking the rest.


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PostPosted: Thu Aug 30, 2012 10:59 am 
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Here's the schematic of the original section of the board with what my modification:
Attachment:
cicremove-schem.png
cicremove-schem.png [ 9.47 KiB | Viewed 3129 times ]


Red Xs are removed, green is what I had you add, purple codes are the names of things on my NES-CPU-07 board, the blue resistor is unnecessary but let me explain:

At least one game uses the CIC SLAVE RESET output to reset its state. (It's the European multicart Tetris+SMB+Nintendo World Cup). But putting in a large resistor (100k?) from pin 6 to 10, you can make sure that 1- that's a large enough resistor that any CIC stun circuits won't damage anything and 2- that game (and any others) that use it will actually go back to the main menu when you hit the reset button.


jims cool wrote:
i think that circuit would zap pin 2 of U9
No, it won't, the only difference from the original schematic is that now the 1-2 inverter is now driving three inverters and the 2A03 and 2C02 reset inputs instead of just two inverters.

Quote:
pin 2 of U9 is output it's tied to pin 3 and 13 inputs. pin 4 is connected to the clock input of the CIC or -5v zapper circuit.. so it could be bad for some games
No stun circuits ever drove CIC CLK for precisely this reason; exceeding the voltage limits of the 74'04 wasn't going to let them run. All CIC stun circuits drive one of CIC pins 1, 2, or 10.


satchsatch33 wrote:
I noticed that I have a NES-CPU-10 mainboard, and you suggest to remove some caps and resistors.

I can only speak for the NES-CPU-07 board, because I can look at it in front of me. I see no reason to remove either of the capacitors (also labeled in my schematic above). They'll just float now, which is safe if superfluous.

Removing the diode, on the other hand, has a point, if you have any unlicensed games with CIC stuns. Because you don't have a reminder that the CIC stun is shorted out (game endlessly rebooting), it could cause the CIC stun to burn itself out.

rainwarrior wrote:
Isn't it safer/easier/simpler to replace it with a chip from a game cartridge?
Desoldering two ICs and resoldering one IC -vs- desoldering one IC and soldering in 2 wires and two passive components? I personally think the latter is easier.


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PostPosted: Thu Aug 30, 2012 11:23 am 
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you need to lift U9 pin 4 (cart cic clock) in your circuit for nothing to be wrong its input is connected to pin 2.. the resistors are just extra junk but you should remove the diode it's job is basically to short out a -5v spike from a third party game.

so if you lift pin 4 on u9 and take out the diode it does the same
my extra 2 inverters connect to the ground and his connect to the reset but that's alright he has one less jumper

without lifting the pin you send a clock pulse out into oblivion.. and if that diode is in the circuit things could get cooking :lol:

and i was talking about the clock driving the -5v not the -5v driving the clock output/zapping it

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PostPosted: Thu Aug 30, 2012 11:36 am 
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jims cool wrote:
you need to lift U9 pin 4 (cart cic clock) in your circuit for nothing to be wrong its input is connected to pin 2.
... yes, pins 2 and 3 are connected? But no cic stun circuits drive CIC CLOCK, so why does this matter?

Quote:
without lifting the pin you send a clock pulse out into oblivion.
Since both of our designs remove the 4MHz resonator, you clearly don't mean "clock pulse"; what do you mean?

Quote:
and i was talking about the clock driving the -5v not the -5v driving the clock output/zapping it
Same thing, really. The only question is which side dies first.


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PostPosted: Thu Aug 30, 2012 12:37 pm 
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i know more about electronics then you probably think :lol: it's not a big deal to me.. you can have a difference in opinion but personalty i wouldn't send a 1hz pulse on to the cic clock line.. it doesn't need the pulse and it's not meant for it. the diodes will short the zapper thats what they do.. if you look at the photos the orange glass things with a blue tripe are diodes... on cpu-10 it's only marked as a capacitor

anyway that was my last reply to this thread.. i think i explained it in this message best :D

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PostPosted: Thu Aug 30, 2012 12:42 pm 
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Don't you think that it's finally better for me to remove a 10NES chip from a dead cartridge (if I found a broken one, for example) and try to resolder it ?


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PostPosted: Thu Aug 30, 2012 3:43 pm 
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I'm sure lidnariq and jims cool have solutions that work well, but I do personally think it's easier just to replace the chip. It's not like the chips are hard to find, and the end result will require less modification to the NES. I don't like desoldering in general, but a small chip like that isn't a big deal, and you already have to desolder the one you need to remove, why not two?


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PostPosted: Thu Aug 30, 2012 3:45 pm 
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jims cool wrote:
i wouldn't send a 1hz pulse on to the cic clock line.. it doesn't need the pulse and it's not meant for it.
Except there is no 1 Hz clock anywhere once we've removed the CIC? Sure, the CIC clock line is now an active-high reset, but I've never heard of any devices caring about the CIC clock line ... other than a properly functioning CIC in the cartridge.

satchsatch33 wrote:
Don't you think that it's finally better for me to remove a 10NES chip from a dead cartridge (if I found a broken one, for example) and try to resolder it ?
Not really. Desoldering an entire IC without the right tools stands a good chance of destroying the donor PCB (which you don't care about here), possibly damaging the IC, and the resoldering a more complex solution also stands a chance of damaging the NES mainboard.

Just follow either of our directions. Are you blocking on finding the right size capacitor? Anything where R×C is at least 10ms should be fine. If you want suggestions, what do you have lying around? You could steal the capacitor C8 (which is 0.1µF) from right next to the CIC socket if that's what you're having trouble finding.

rainwarrior wrote:
I'm sure lidnariq and jims cool have solutions that work well, but I do personally think it's easier just to replace the chip. It's not like the chips are hard to find, and the end result will require less modification to the NES. I don't like desoldering in general, but a small chip like that isn't a big deal, and you already have to desolder the one you need to remove, why not two?
I was acting under the impression that he'd already completely removed the CIC off the mainboard.


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PostPosted: Fri Aug 31, 2012 1:54 am 
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Hi Lidnariq,

As I said previously, I don't speak english very well (maybe you have notice it).
I was mistaken, so I wanted to say that I was looking for an advice (instead of a suggestion).

I think I will try your solution first, I think it's more easier than Jims's solution, and, as I said, I'm a begginer in electronic stuff.

I guess that it will be not hard to find the capacitor you are talking about, I have and electronic shop near of my house.

I have 2 another questions please : since I've removed the 10NES chip, broken pins stays on the mainboard. Do I have to remove them (and just left holes clean) before making a soldering stuff ?
If I want to "region free" this mainboard, what I have to do ?

Thanks


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PostPosted: Fri Aug 31, 2012 10:00 am 
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It seems to me that you are way better off just cutting or lifting the Key/Lock pin. Far less work and same result.


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PostPosted: Fri Aug 31, 2012 12:44 pm 
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I don't understand (I don't speak english very well).

What do you recommend to me ?


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PostPosted: Fri Aug 31, 2012 12:50 pm 
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satchsatch33 wrote:
I guess that it will be not hard to find the capacitor you are talking about, I have and electronic shop near of my house.
So, I've been thinking about it for the past few days, since you don't have the capacitor lying around. So I just tried removing it. It works fine, because there's another capacitor (C8) on the board for the same purpose.



Alternatively: I have not yet tried this myself, but this minor variant on my previous design does not require that you buy any parts, not even a resistor. (obviously you still need wire)
Attachment:
cicremove.png
cicremove.png [ 3.96 KiB | Viewed 3052 times ]
For this you'd still need to remove the CIC, the 1Mohm resistor, and X2, but then resolder the 1M resistor as shown in dotted lines (It should reach) and add the two shown wires.

Quote:
I have 2 another questions please : since I've removed the 10NES chip, broken pins stays on the mainboard. Do I have to remove them (and just left holes clean) before making a soldering stuff ?
Only the ones that you want to solder things into. It'd look prettier if you removed them, but you're the only one who'll know.

Quote:
If I want to "region free" this mainboard, what I have to do?
A NES that lacks its CIC can play all games from Japan and the US, and probably most games released for Russian and Chinese famiclones. Games from Europe may or may not work and may sound detuned.

You're welcome.


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PostPosted: Fri Aug 31, 2012 1:19 pm 
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You told me that you don't have already try it......I'm afraid to try this.......

Have you tried you first schematic ? Did it worked ?


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PostPosted: Fri Aug 31, 2012 1:50 pm 
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The first schematic, but just omit the capacitor. I tried it two hours ago and it worked fine.


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