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PostPosted: Tue Feb 06, 2018 6:21 pm 
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Joined: Sun Jan 21, 2018 3:10 am
Posts: 2
Hello everyone,
I found my old NES console and gave it a try. Unfortunately, it has a mysteriouse problem.
If I turn it on nothing happens - no red LED, no picture - :?

But when I just left the console on - suddenly AFTER 2 MINUTES the red LED went on and a black picture appeared. :shock:

This can even be replicated, but nothing more , just the black screen.

What I've done so far:
- Tried various NES power supplies and connectors
- CIC chip disabled
- CIC chip exchanged
- all IC´s are socketed and have been replaced with working ones
- Electolytic Capacitors replaced on the whole board and Video power board
- unsoldered video/power board and soldered the power supply directly via USB
- No IC chip gets hot (have already been checked)


Therefore, I assume that the fault lies directly on the main NES PCB . Now I am wondering which part could lead to this strange symtoms. Maybe a tantal capacitor ?

Has anyone ever had such a problem or has an idea which component could make such a mistake?

I would appreciate any hint or suggestion :o

Best regards
Sarah


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PostPosted: Tue Feb 06, 2018 6:26 pm 
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Joined: Sun Apr 13, 2008 11:12 am
Posts: 6810
Location: Seattle
Check the 4MHz ceramic resonator used by the CIC.

My guess is you'll see something closer to 40kHz than 4 MHz.

If so, you could try the "add two wires" CIC disable.


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PostPosted: Wed Feb 07, 2018 6:33 am 
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Joined: Sun Jan 21, 2018 3:10 am
Posts: 2
Hi lidnariq,

thanks for your reply. :D


"Check the 4MHz ceramic resonator used by the CIC."

I forgot to mention, that I already replaced the 4MHz ceramic resonator , but I got it from an old famicom , maybe it isn´t good either.
(I think it should be ok since both work with the NTSC standard)

I tried the "2 wire method" today , but unfortunately it is still not working :(

any other ideas ??
Thanks a lot


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PostPosted: Wed Feb 07, 2018 7:18 am 
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Joined: Fri Nov 12, 2004 2:49 pm
Posts: 7376
Location: Chexbres, VD, Switzerland
Are you sure the delay is consistent ?
I'd lean towards a bad contact on the power supply connector's side or something in the like.


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PostPosted: Thu Feb 08, 2018 1:25 pm 
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Joined: Mon Jan 11, 2016 11:39 pm
Posts: 21
Take out the power and reset button assembly and check for continuity along the traces if you have a multimeter. Check for continuity between the inputs of the power switch. I recently had a disgusting NES I cleaned up and the contacts in the power switch didn't work. You can open it up and file it down with an emery board and clean it up with alcohol.

Also if you have a multimeter, check for 5V DC on the CIC chip Vcc and check pins 7 and 9.


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