Repairing a ZX Spectrum 128K +2 (serial no U-043583) - Part 2

In part 1 I fixed the manufacturing fault which resulted in no output on the composite video but the resultant image was terrible.

Spectrum composite video on LG 32LB650V

The screen is covered in dots which do not move and seem to only appear on alternate lines. I do not think these dots are caused by a fault reading from memory as they also appear on the spectrum's border which is not read from memory.

I tried a SCART to HDMI convertor and the dots are gone so it turns out my LG TV (model 32LB650V) does not like the composite video from the spectrum. Maybe it is confused by the progressive PAL signal?

SCART to HDMI adapter ghost image

The dots and lines are gone but now there is a ghost image on the composite video.

Composite to SCART adapte

At this point, I tried another spectrum +2 using the SCART to HDMI adapter and got a perfect image so this ghost image must be due to a fault with the spectrum.

I lashed up a temporary RGB cable and tried that via the SCART to HDMI adapter and the ghost image was not present to I think the problem is something to do with the composite video circutry. Part 3....