Entertainment Center: TVs, Stereos, VCRs and DVDs - Philips TV "blue" channel problem

Hi All,

I've got a 4 year old Philips 32PW8505 (Chassis MG2.1E) . On start up everything works fine . After about an hour or so the "blue" signal starts to fluctuate between dark blue and light blue continually . Not in regular shifts but as if a component is breaking down . If there's no blue in the picture then it's not noticable but with no signal (blue background) it's easily seen . Obviously it makes normal TV viewing difficult . It happens on all inputs , RF and SCART . I've got the schematic but no service manual . It may be the tube but I don't want to go inside it until I get a bit more info . Any help or pointers would be appreciated .

Paul

If you have a schematic you can hook a scope probe to the RGB amplifiers without a signal and see if what comes out corresponds to black level (the schematic should tell you the dc offset voltage should be). If you find that there is a residual dc on the blue amp you can trace back to the color mixing amps and if necessary back to the chorminance and luminace channels to see if the level are abnormal. Again schematics usually say what voltage you should see at key test points.

Thanks rav12 for the info . Actually , I've just called the Philips repair centre and they're coming out to look at it on Monday . As it's intermittent and also CRT related I thought it best to let the specialists handle it .
Thanks anyway for the help .

Paul