Quote:
Originally Posted by mark pirate
After a couple of minutes the picture darkens from the centre and then 'balloons'. I am hoping the LOPT is ok, and it is just down to leaky old caps.
I am hoping someone familiar with these sets can point me in the right direction with this fault. Mark
|
Hello,
I have the same set and unfortunately, it quickly got through two LOPTs (I did change all the usual suspect Philips style black wax caps, etc.). Your set doesn't seem to have these, rather the dark green Polyester type, which are usually very reliable. I'm assuming they are the early version of the Philips/Mullard C296 series, which have the beige/"mushroom" colour cases.
I'd also check the line osc (ECL80), line output (PL36), boost diode (PY81/800) and EHT rec (EY86/7) valves first, before suspecting the LOPT.
In any event, I would check the boost HT reservoir capacitor (by replacement with a moderm Polypropylene type) and if it still plays up.....! At least these LOPTs aren't sealed with black pitch or wax. Note that, IIRC, two slightly different types of LOPT were fitted in this chassis (it is covered in the Philips service manual).
A stock fault on these is the 2.2M focus slider pot, which goes low, dragging the Boost HT line down. It's on the CRT base connector. I'd check that first and just snip it out of circuit for the time being.
Good luck,
Dazzlevision