Cyan Discoloration on Flesh Tones

This is a odd symptom to describe. It is a CTC187 RCA television. Caused by tuner misalignment. It can effect 1 or two channels. Never shows up in the video input mode. What's occurring is a 180 degree phase shift of the chroma signal which represents this woman's skin tone.

This trouble was caused by not aligning the tuner after the EPROM was replaced on a earlier service call.  The trouble was not immediately discovered by anyone until about 6 months later when the customer moved to an area not served by CATV. With an outdoor antenna the television began to manifested this symptom on just 1 channel. Channel 12 in Phoenix, Ariz.

All parameters used to align the tuner were 31. This is the default value placed in all new EPROM's. Aligning the tuner with the Thomson TAG-001 signal generator corrected the symptom.
 

Dennis Viereck
:wa6ati@dslextreme.com