The Sinclair QL Forum

Good morning, all,

I have just joined the forum and would first like to say hello to you all!

Next, could anyone tell me if this display is normal or is something wrong with my QL? I don't have an RGB cable so I am using the dreaded UHF output.

Thanks in advance.

UHF is particularly poor in the QL and the modulators may not have aged well. But yeah it may be as good as you can get on a modern TV with that modulator. It could also be a faulty mc1377p causing the ghost effect but more likely the modulator.

I wouldn't necessarily blame the modulator (or even the QL) at all:

Relatively modern TVs generally tend to have more problems with picking up and syncing to a primitively generated UHF signal from old computers (not just the QL). They are much more picky than good, old CRT TVs. I have a ZX81 that displays a (relatively) nice picture on my old CRT TV, but won't sync at all on a modern flat screen.

Obviously, modern TVs haven't been optimized to tolerate shaky signal input on a technology that is rarely (and, in many countries, no longer at all for quite some time now) used for the intended TV operation. The other reason is that Sinclair's tendency to bend the rules of what an "acceptable" RF signal is, went quite a bit far on the QL, even for contemporary TVs (the lines ar just way too long).

Thanks for the responses. The reason for my question is because I did have another QL that produced a reasonable picture via the UHF output. I therefore wanted to check.
I have a spare MC1377P so I will swap it for the other one and give it a try...if I can remove the thing!

it's normally socketed, so an easy in and out. I have spare 1377p's if you find you need one.

Thanks JobDone.
I swapped them over and it made no difference at all.
I think I will buy an RGB to Scart lead!

I can recommend the rgb2hdmi and the picovga both have the advantage of a full screen f1. I noticed you were using a CRT on second look so the scart may be an easy option

Yes, my main CRT classic machine tester is an early 90s Sony TV. I tend to get a good picture on all my old machines with this TV.

In the past I experienced similar results, due to a weak/faulty PSU. Unless you used the same PSU for both machines, you may try tho swap the PSU - just to make a test.