View Single Post
Old 16th May 2007, 9:31 am   #9
Mike Phelan
Dekatron
 
Mike Phelan's Avatar
 
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,609
Default Re: Pye CT205 - a partial success story!

Tas
Quote:
Originally Posted by Tazman1966 View Post
By the way would a dodgy PL509 have killed R203?
No - if the LOP stage is not running, there will be no current through it.
It is a stock fault - despite the fact that it seems not to need 2 watts, the line pulses cook it. Sometimes takes the two flywheel diodes as well.
Other suspect resistors while you are here are the 1K5 (?) across the line lin control and the one (100K?) in series with the line hold control.

Quote:
The odd blue greyscale fault looks a bit like blue lateral mis-convergence but it isn't and of course having colour difference drive to the CRT means that there won't be flareing which could be mistaken for mis-convergence.
Don't know what you mean by that - CDA drive simply means that the luminance (Y) component is subtracted by the CRT instead of earlier on.

Steve's advice is good; as we used to say, "get it right in black and white" before looking for a colour fault.

If the blue seems smeary (poor HF response) turn the colour and red and green guns off and use a crosshatch.
It is probable that the fault is not before the CDA panel - if you pull the two leads out from the chroma signal that will prove it.
I have had the capacitors go O/C between the two anodes of the PCL84 with similar results.
Swap the CRT leads to see if the fault is on the CDA.

HTH
__________________
Mike.
Mike Phelan is offline