Hi everyone,
I've got a sod of a TV set here which is puzzling me and I hoped that someone here more knowledgable than myself might be able to offer some advice.
It uses the L01.1E chassis and is a 32" widescreen. Originally it was tripping which turned out to be S/C line output transistor (or HOT as some call it), probable cause being C2455 (47uF/25V) in the line driver circuit, low in value at 36uF. This is apparently the usual cause with this chassis, and there is also a PSU kit available for the SMPS in the event that the set continually kills the line output transistor.
Anyway, replaced the transistor (BU4508DX) with a BU2508DF and replaced the cap with the only available one (47uF, 63V). The set now comes on. I don't know if it's usual behaviour for this set, but it takes a while for the raster to appear, during which a couple of relays click. After 2 or 3 seconds or so, the set then shuts down. It seems the line drive is taken away when this happens, as the HT line rises from its value of 126V under load, to its 140V unloaded potential.
Although it shuts down quickly, I found that I could keep it on longer by going through the channels; it seems to stop the shut-down process. I brought up a channel with a very good undistorted image, stopped flicking through the channels, leaving it one this one, and then the set died after a few seconds as normal. The transistor doesn't seem to be getting terribly hot during this.
Incidentally, it may just be me, but the line stage doesn't sound right... the high-pitched noise coming from the LOPT seems to have harmonics by the way there is a 'flicker' or 'roughness' to it. It's hard to describe.
Any ideas or suggestions would be much appreciated as this has been on the bench too long now and I'm tired of its 32 inches taking up most of the workspace and falling over its gigantic rear cover!
Thanks to all who even read this, and especially to anyone who replies.
James