NESRGB black screen at boot

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RayDreamer
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NESRGB black screen at boot

Post by RayDreamer »

[Edit]: Tim was able to figure out the issue after troubleshooting a console from someone with the same problem. Tim outlines the fix here: https://shmups.system11.org/viewtopic.p ... 1#p1511761
I did also install the V.2.1 firmware too that increased the startup time for the microcontroller. https://etim.net.au/nesrgb/NESRGB4_MCU_firmware
My console is working great now with no issues. No blinking reset LED and the palette is selected automatically.

Hopefully somone may know why this is happening.
I had installed Tim Worthington's 4.0 RGB kit in my front loading NES and am having a problem with a black screen at when turning it on.
I did install the 220n capacitor included with the kit.
The kit is outputting sound at boot, and if I use the button combos to select a palette I am able to get picture that way. The picture seems to be fine, and I'm able to cycle through the palettes and reset the console via the button combos. It's just the initial power-up that's not working.

The LED for the power up reset blinks for about 4 seconds at boot and then stabilizes.
Here is an Imgur album with pictures of my install: https://imgur.io/gallery/FXzuzYM

I also have installed Merlin Shaw's replacement NES power module. Specifically, the "NES Classic" version he had sold on eBay before (https://github.com/ShawMerlin/NES-Power-Module-Redesign).
Last edited by RayDreamer on Sat Dec 17, 2022 1:39 pm, edited 3 times in total.
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TmEE
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Re: NESRGB black screen at boot

Post by TmEE »

It sounds like you need to set the default palette jumpers to something other than "no output" setting
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RayDreamer
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Re: NESRGB black screen at boot

Post by RayDreamer »

TmEE wrote: Thu Dec 01, 2022 2:39 am It sounds like you need to set the default palette jumpers to something other than "no output" setting
I'm assuming you're talking about the 1-3 pads on the bottom right of the board you'd jump to the ground pad or connect a switch to select a palette.
I went for the button combo install new to the 4.0 kit, which has you select palettes through a button combination (https://etim.net.au/nesrgb/NESRGB40.html). In this install the instructions say you don't even use the ground pad.
Unless maybe you're talking about something else.

I believe the board's supposed to remember my last used palette in this mode. But it's throwing the LED error that says it's not getting power quick enough. Which I imagine is why I'm not getting picture without manually setting a palette.
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TmEE
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Re: NESRGB black screen at boot

Post by TmEE »

"The design of NESRGB version 4, which uses a RAM based FPGA and a helper microcontroller to read the controls, requires a bit of extra time to start up when the console is switched on. The power on reset delay of the front loading NES is too short so its timing capacitor must be changed to accommodate this. Start up delay on the Famicom consoles is normally fine as it is, but a replacement timing capacitor is included with the kit just in case it has failed. The NESRGB can detect if the timing delay is incorrect and will blink LED 7 at power up if this is the case. A fast blink means the timing capacitor must be replaced. A slow blink means it is marginal."
I suppose this was also done ? It sounds like it is what is happening.
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RayDreamer
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Re: NESRGB black screen at boot

Post by RayDreamer »

TmEE wrote: Thu Dec 01, 2022 9:13 pm
"I suppose this was also done ? It sounds like it is what is happening."
I installed the capacitor that is talking about.
I had emailed Tim with the same info and pictures as this post and he just got back to me. He said that he had a few people contact him with a similar problem I'm having.
He said that with everything mine is doing "it's most likely a fault on the NESRGB board," and says the culprit is "specifically, a bad solder joint on the microcontroller." The micro controller is the little chip directly above the "RO" via.
He said it's possible for me to fix it but I would need to have a hot air rework station, which I do not have. I don't know if the issue is more than just reflowing the solder pads along the legs. But given that couldbe reflowed with just a soldering iron I don't know. I did ask Tim if that's it.
Tim said he'd arrange for me to get a new board if I don't have a hot air rework station, which it looks like I'll probably have to do.
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RayDreamer
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Re: NESRGB black screen at boot

Post by RayDreamer »

Alright, so after emailing Tim he found that it's caused by a bug in the FPGA firmware. Tim goes into more detail for what caused it here: https://shmups.system11.org/viewtopic.p ... 1#p1511761

Luckily, the fix is pretty easy. It can be solved by cutting pin 22 on the pin headers on the underside of the NESRGB, isolating it with electrical tape, and then soldering in a 1k resister between pin 22 and pin 40. Tim provided pictures on the link as well as more info.
Tim said told me before that this isn't an issue with a ton of boards so hopefully this is solved going foward.

Initially, Tim thought it was an issue with the microcontroller, which he addressed in firmware version 2.1 https://etim.net.au/nesrgb/NESRGB4_MCU_firmware/
I don't know if that firmware is strictly needed in conjunction with the other fix as I didn't downgrade my firmware to check. I would probably just do both if I had to do it again.
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