How to fix a NES mainboard without 10NES lockout chip ?

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

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dphirschler
Posts: 4
Joined: Sat Dec 08, 2018 5:37 pm

Re: How to fix a NES mainboard without 10NES lockout chip ?

Post by dphirschler »

Everything works as you'd expect... except I get gray screen. I see the red power LED. The Reset button resets. What could be going on?

Darryl
lidnariq
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Location: Seattle

Re: How to fix a NES mainboard without 10NES lockout chip ?

Post by lidnariq »

Red power LED is on, but off while reset is pressed? Video draws solid-colored screen, but is off while reset is pressed?
dphirschler
Posts: 4
Joined: Sat Dec 08, 2018 5:37 pm

Re: How to fix a NES mainboard without 10NES lockout chip ?

Post by dphirschler »

OK, update on this Nintendo NES. I now believe the lockout chip removal was successful.

I'd long suspected this NES of having power issues, so I just replaced the 7805. Cheap and easy repair. Then I did further testing with it. Still got the gray screen, but since the lid was off, I fiddled with the cart and as I raised and lowered the angle of the cart, it suddenly came to life! Not sure if the trouble is where the 72pin meets the mainboard or where the cart plugs in, but I suspect it's where the cart plugs in.

But the lockout mod seems successful. I should be play testing this thing later tonight after I get the 72pin issue worked out.


Darryl
dphirschler
Posts: 4
Joined: Sat Dec 08, 2018 5:37 pm

Re: How to fix a NES mainboard without 10NES lockout chip ?

Post by dphirschler »

Last update. I bent the pins on the 72pin connector and I have the NES working reliably now. Best of all, the lockout chip removal was a success! Thanks all.

If anybody else attempts this mod, it would be best to only change one thing at a time. Had I done that, I would not have been wondering which thing was causing my issue.

Darryl
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rainwarrior
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Re: How to fix a NES mainboard without 10NES lockout chip ?

Post by rainwarrior »

I just wanna say I'm glad this thread is still here. Wanted to replace a potentially dead CIC and this had exactly the info I needed.

Also I'm surprised to find myself advocating for replacing the chip earlier in the thread, ha ha. I think my tolerance for desoldering work has drastically reduced in the years since.
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