Grey screen. Probably my fault. Can it be revived?

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Grinlord
Posts: 1
Joined: Mon Dec 28, 2020 1:29 pm

Grey screen. Probably my fault. Can it be revived?

Post by Grinlord »

I dabble with soldering projects but have little experiencing repairing things at a component level. I recently pulled my unmodified one-owner NES out of storage to setup a retro gaming room in my loft, which has been great, except for the NES.

Initially it would only play some games with repeated re-inserting of cartridges and a squirt of contact cleaner.

I did some research and found out how to cut the pin of the 10NES chip. This was successful, so I now knew that this chip wasn't the culprit.

I did some more research and learnt how to bend the cartridge side of the 72 pin connector to make better contact. This helped a bit. I then learnt to boil the 72 pin connector. While it was apart I cleaned the contacts on the motherboard, but this is where I messed up. Without reading first, I assumed that nail varnish remover and a fibre pen would dissolve and clean the contacts, but I have since learnt that the acetone in the nail varnish remover was potentially very harmful. Now I can not make any game boot up. I just get a solid grey screen.

I bought a new cheap 72 pin connector but this didn't help. I bought a security torx tool and opened a cartridge, and this time cleaned it with alcohol sanitiser (over 75% alcohol) and cardboard. I did the same to the motherboard contacts and produced a good shine on both. I tested the cartridge end of the 72 pin connector for continuity on every pin to the motherboard and this passed, but still the cleaned game won't boot. I tried two other games for good measure which also wouldn't boot. This is what my motherboard and the cleaned game look like now:
MB top.jpg
MB under.jpg
cart top.jpg
cart under.jpg
I boiled the original 72 pin connector again and refitted it, and again it passed continuity to the cartridge end, but didn't help the problem.

I found the following post on here about someone who had the same symptoms (but not necessarily self inflicted damage), and eventually diagnosed a faulty RAM module. I don't know how to test this:
http://forums.nesdev.com/viewtopic.php?f=9&t=16567

I also don't know if these solder joints look suspect?
poss bad joints.jpg
I have tested my external PSU and verified 10vac unloaded. Not sure what voltages I should probe for inside.

Hope you can help me revive my original NES without having to replace it.
GaryTheCat
Posts: 3
Joined: Tue Mar 29, 2022 8:53 am

Re: Grey screen. Probably my fault. Can it be revived?

Post by GaryTheCat »

Hi Grinlord,

I'm facing the exact same symptoms, Grey Screen. I ordered a logic analyzer to test my CPU. If I find anything, I'll let you know.

Hopefully we don't have to find replacement CPUs or PPUs. :(

Also, is it modded with NESRGB?
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Ben Boldt
Posts: 1149
Joined: Tue Mar 22, 2016 8:27 pm
Location: Minnesota, USA

Re: Grey screen. Probably my fault. Can it be revived?

Post by Ben Boldt »

I am not seeing how the nail polish remover or fiber pen damaged the NES motherboard. It looks like some solder mask went away but that shouldn't really be a problem. Did you get any of the nail polish remover in/on the plastic ZIF connector? That may have caused a problem with the plastic, which may dissolve and distort from the acetone. I think the motherboard is OK as far as I can imagine. Take a closer look at the connector. Be sure to touch one of the metal shields before touching any of the contacts just in case of ESD.
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