A friend gave me a very nice NES frontloader with a few games, 2 controllers, and even a Zapper! Nice!
Sadly, it has the red blink of death, which I thought to be either a dirty cartridge connector, a bad NES10 chip, or both! I decided to pull it apart, clean the connector, and disconnect pin 4 of the CIC/NES10/Lockout chip.
Originally, I'd wanted to desolder the whole chip, neatly bend the pin up, and solder it back in sans pin 4, but my gas-powered soldering iron just couldn't generate enough heat to wick the solder up into the braid.
Next, I tried snipping the pin... but my diagonal cutters were too big. I was able to "nick" the pin, but not cut it.
In my impatience, I used a tiny screwdriver to break the pin at the nick, but sadly the pin pulled out from the IC instead. Not proud of that, I should have waited until I had proper tools. I didn't think it would matter though, as the pin is now disconnected. Besides, I've seen way worse hackjobs on the internet, and the authors of those guides didn't indicate any issues.
When I put the NES back together, I now get no power light. There's a slight "pop" on my TV's audio when I press the power button, but nothing else. Video remains black. Did I ruin my CIC/NES10/Lockout chip? Would a ruined chip keep the console from starting? Should I desolder a NES10 chip from a game (a lame one), and solder it into my console with pin 4 neatly bent away?
No power LED after breaking pin 4 on lockout chip
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Re: No power LED after breaking pin 4 on lockout chip
You do not need the CIC IC to be present.
You can add two wires: https://forums.nesdev.com/viewtopic.php?t=10091
You can remove the CIC and 4MHz resonator, move the 1MΩ resistor, and add two wires: https://forums.nesdev.com/viewtopic.php?p=98871#p98871
You can add two wires: https://forums.nesdev.com/viewtopic.php?t=10091
You can remove the CIC and 4MHz resonator, move the 1MΩ resistor, and add two wires: https://forums.nesdev.com/viewtopic.php?p=98871#p98871
Re: No power LED after breaking pin 4 on lockout chip
Should I give that a try in it's current state? I can easily add those two wires with the tools that I have.lidnariq wrote:You can add two wires: https://forums.nesdev.com/viewtopic.php?t=10091
Any idea why the console appears to be dead?
Re: No power LED after breaking pin 4 on lockout chip
Yeah, try adding the two wires.
The CIC is the device that drives the "power" LED (hence why it blinks when the CIC fails), so if something went wrong with the CIC, it could never release reset and never light the LED.
The CIC is the device that drives the "power" LED (hence why it blinks when the CIC fails), so if something went wrong with the CIC, it could never release reset and never light the LED.
Re: No power LED after breaking pin 4 on lockout chip
That worked beautifully, thank you very much! I went from a seemingly dead console with no power light to full function by soldering in those two wires. I ended up using the first example (yellow wires) instead of the second (white wires), because my unit was missing a pad from the second screenshot. I'm pretty sure it was on a big ground plane, but I didn't want to be wrong.lidnariq wrote:Yeah, try adding the two wires.
After cleaning up the rest of the console and cleaning out the controllers, we've been playing it for a couple of hours with no issues.
I wonder if this would work if pin 4 was not disconnected at all? If so, that would be much safer and easier than trying to disconnect pin 4 from the CIC IC. I can't quite tell from the other thread whether the lockout chip still needs to be there for this to work.
Re: No power LED after breaking pin 4 on lockout chip
Yes, the two wires defeat the CIC altogether.
One wire keeps the 4MHz clock from operating and thus keeps the CIC from executing any code; the other wire converts the signal from the reset button to the format needed by the CPU and PPU.
I'm pretty certain that the two wires would still do the right thing even if the CIC IC were missing altogether, but I haven't actually thought about it.
I came up with the "add two wires, remove CIC and clock, move resistor" plan before I was made aware of the "just two wires" mod, and I haven't really thought about it since.
One wire keeps the 4MHz clock from operating and thus keeps the CIC from executing any code; the other wire converts the signal from the reset button to the format needed by the CPU and PPU.
I'm pretty certain that the two wires would still do the right thing even if the CIC IC were missing altogether, but I haven't actually thought about it.
I came up with the "add two wires, remove CIC and clock, move resistor" plan before I was made aware of the "just two wires" mod, and I haven't really thought about it since.