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SiriusHardware · 11th Mar 2020, 9:16 pm

If the composite modification was done in the usual way, yes, that's the reason.

Normally it's done in the modulator housing and in its simplest form the modulator's input and output are disconnected inside the modulator housing and the video-in signal is then taken straight to the centre terminal of what was originally the UHF-out socket.

If so, your Spectrum is no longer outputting a UHF signal, only a composite video signal, so a normal TV will no longer be able to receive it through the aerial input. If the TV in question has a yellow 'AV IN' phono-type socket (same as the one on the modulator), that would be the place to connect the Spectrum to now.

11th Mar 2020, 9:16 pm	#2
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,586	Re: ZX Spectrum Tuning Issue If the composite modification was done in the usual way, yes, that's the reason. Normally it's done in the modulator housing and in its simplest form the modulator's input and output are disconnected inside the modulator housing and the video-in signal is then taken straight to the centre terminal of what was originally the UHF-out socket. If so, your Spectrum is no longer outputting a UHF signal, only a composite video signal, so a normal TV will no longer be able to receive it through the aerial input. If the TV in question has a yellow 'AV IN' phono-type socket (same as the one on the modulator), that would be the place to connect the Spectrum to now.