A new hardware problem for me.

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems.

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Sleepallday
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Joined: Sat May 09, 2020 3:52 pm

A new hardware problem for me.

Post by Sleepallday » Sat May 09, 2020 4:03 pm

It's a toaster nes.

I've got 3 test games. Mario duck hunt loads no issues. Joust and 10 yard fight load only after being powered on hitting reset.

All caps have been replaced. 7805 is replaced. Official and fake power adapters tested. The cartridge connector has been cleaned with ipa and boiled but is still original. Cic chip has been cut and disabled.

Any guesses?

Thanks

lidnariq
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Re: A new hardware problem for me.

Post by lidnariq » Sat May 09, 2020 4:13 pm

When you only cut pin 4 on the CIC, it's still responsible for handling the timing of reset to the CPU and PPU. If these two other games reliably work after reset, you could try the "two wires" CIC disable instead.

Sleepallday
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Re: A new hardware problem for me.

Post by Sleepallday » Sat May 09, 2020 4:23 pm

Thanks that's on the list tomorrow. I'll report back. I was also considering pulling the cartridge connector out of my childhood nes to test. That console works perfectly. It could likely use a cleaning inside that console anyway.
I'll try your mod first though.

Sleepallday
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Re: A new hardware problem for me.

Post by Sleepallday » Sat May 09, 2020 4:42 pm

Also if a put a game in and don't power it on for about 10mins then power it on the game will load. This happens every time with all games. It seems to want to sit for a bit or have its reset button hit to load a game.

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Memblers
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Re: A new hardware problem for me.

Post by Memblers » Sat May 09, 2020 5:23 pm

You could also look at the power switch. If you're going to have your other NES apart, you could test the other switch assembly, easy since it is connectorized.

I've had to clean the switches before, it was frequently causing the NES to crash. The switch itself could be disassembled if you really wanna get at it, it's held together by plastic tabs. Symptom sounds similar, but in my case the problem was intermittent (but getting worse), and yours is every time.

Sleepallday
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Re: A new hardware problem for me.

Post by Sleepallday » Sat May 09, 2020 5:46 pm

Added to the list. Thank you. I wonder why I feel like I'm on a mission to save something worth 40 bucks on a good day. I will fix it!

Sleepallday
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Re: A new hardware problem for me.

Post by Sleepallday » Sun May 10, 2020 9:13 am

K so I swapped the cartridge pins from one machine to the other and no difference. I tried using the different power/reset switch. Still no difference. I even replaced the capacitor in joust still nothing.

I don't know much about how the nes powers on and does its check but everything seems perfect every time if I just hit reset after the power on. Is there something in the power on sequence?

lidnariq
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Re: A new hardware problem for me.

Post by lidnariq » Sun May 10, 2020 10:45 am

The delay of power on to reset is determined by the capacitor attached to CIC pin 3 normally. (The CIC has a weak pullup inside) But you said you recapped everything, so I assume that includes the CIC's 2.2µF capacitor there.

I don't know how timing will change with the "two wires" mod.

Sleepallday
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Re: A new hardware problem for me.

Post by Sleepallday » Sun May 10, 2020 12:45 pm

Ya I pretty much said good enough. I found a copy of dick Tracy and that seems to work fine anyway. Yep the 2.2 was replaced.

I'm wondering if there's a way to send a reset command to the board after it powers up?

lidnariq
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Re: A new hardware problem for me.

Post by lidnariq » Sun May 10, 2020 12:59 pm

You could try replacing the 2.2µF capacitor with a larger one, so that the CIC takes longer to come out of reset, so that the CPU is held in reset for longer.

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