no color in a vestel tv

[thfixer]

Hello very one i have tv ,i think it is vestel, having processor st 92195c3b1/oEo+stv2247h+24c08a.there is no color ,sometimes it is color ,sometimes not.any one to help me with this ,thanks in advance.

[torbjorn]

Do you have the same problem regardless of if the tv is receiving a RF signal or if you supply a composite or Y/C signal to the scart connector?

Check with a scope that the video signal at the input to the PAL decoder is in good order - correct amplitude of the color burst, no deformation of the burst or sync pulse etc.
If there is some switching circuitry for component type (Y/C or S-VHS) video signal, make sure that you have chroma signal at the right points after the switches.
Also, try alignment of the subcarrier oscillator according to the tv's service manual.

[thefixer]

I replaced stv2247h with stv 2246h and quartz ,so the color is stable: tv is ok now.