I have an original NES from England that I bought in the early 90s. I just found it again in the attic, and I want to hook it up and start playing it again. However, I now live in the USA and it's region locked. Is there any way around this?
There are two critical differences between an NES made for the UK versus one for the US: the CIC chip and the video output.
The CIC chip is designed to forcibly reset the system any time there isn't a cartridge with a proper matching CIC chip in the slot, but the system can easily be modified to eliminate for a matching CIC chip (or any CIC chip for that matter) in the cartridge.
The video output of a UK NES will be PAL format rather than NTSC. Monitors which are just designed for use in the USA won't work with PAL signals, but some monitors will auto-detect PAL or NTSC and display either kind of signal just fine. Unfortunately, I've not seen such dual-format capabilities advertised as a feature, so I don't know how to determine which ones would work.
The best way to get video on old machines in 2020 is to feed their output to a HDMI converter.
For instance, the video output of the french NES console is SCART, so you have to get hold of a HDMI converter which does SCART. Be careful as there are composite-only converters around. Make sure that the converter supports RGB as well as composite. Those are generally more expensive than composite to HDMI converters but still reasonable (20/30 euros). The also need a 5V/USB power supply.
The video output is not perfect but it's correct given the price.
I have successfully used a RGB SCART (Peritel) to HDMI converter with success first on my Oric and then on a friend's NES so he could ditch his CRT TV. Cost was around 30 euro. Cheaper converters are composite only and the display is black and white (or should I say black and black).
The working ones mostly look like this
The non-working ones can look like this (and are cheaper, but total waste of money)
Once the signal is converted to HDMI, you can connect it to any modern device, not necessarily a TV, but also a computer monitor, which is another advantage: they are cheaper and lighter (but you have to account for the HDMI converter + power supply)
The best possible image quality is achieved by modifying the NES to provide S-Video, RGB, or HDMI output.