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SiriusHardware · 11th Mar 2020, 9:54 am

An 'Image' is a false or secondary weaker signal which a receiver can sometimes 'see' on a frequency some distance away from the frequency which the signal is really on. We were thinking you might be tuned to an image signal rather than the real signal.

Can you check the 'aerial' lead for continuity?

Check that there is zero ohms between the centre pin of the TV end of the lead and the centre pin of the ZX81 end of the lead, and also check that there is zero ohms between the outer part of the TV end of the lead and the outer part of the ZX81 end of the lead.

Finally, check that there is NO connection between the inner and outer parts of the TV end plug (All measurements to be made with the lead just by itself, not plugged into anything).

11th Mar 2020, 9:54 am	#33
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,556	Re: Zx81 An 'Image' is a false or secondary weaker signal which a receiver can sometimes 'see' on a frequency some distance away from the frequency which the signal is really on. We were thinking you might be tuned to an image signal rather than the real signal. Can you check the 'aerial' lead for continuity? Check that there is zero ohms between the centre pin of the TV end of the lead and the centre pin of the ZX81 end of the lead, and also check that there is zero ohms between the outer part of the TV end of the lead and the outer part of the ZX81 end of the lead. Finally, check that there is NO connection between the inner and outer parts of the TV end plug (All measurements to be made with the lead just by itself, not plugged into anything).