I bought a small LCD TV today in part to use with my retro computers. My Sinclair ZX Spectrum 48k works perfectly with it - I can manually fine tune Channel 36 as shown in this video.
With the ZX81 I get frustratingly close. I can see the K icon, and the results of anything I type, but the image will not stay still, and half the time the TV claims there is no input (usually while still showing the flickering image).
I have read the discussion on this forum thread, though it is 10 years old, and not everything is there or linked any more*. Also as I understand it, most solutions involve some replacing/soldering of components onto/into the ZX81 and I absolutely don't want to do that for fear of breaking anything.
Having said that, I have opened up my ZX81 and ascertained that the root of the problem is the ULA 2C184E which, unlike later versions of the ULA, does not control video signal strength.
So my question is - is there an external solution to my ZX81's weak video output?. I'm open to doing some soldering and creating some kind of device, as long as it is external to the ZX81. Or is it impossible to improve the situation without internal modification? Has anybody had success using a generic TV signal boosters with the ZX81 video output to solve this problem?
(As an aside, even in the complete absence of a TV for a time, I was able to use the ZX81, using the printer as a kind of Teletype :-D).
* But the thread does prove that this is not just a problem with my TV, and is a general problem with ZX80/81.