J
JamesQB
- Jan 1, 1970
- 0
Hi everyone
I've got a sod of a TV set here which is puzzling me and I hoped tha
someone here more knowledgable than myself might be able to offe
some advice
It uses the L01.1E chassis and is a 32" widescreen. Originally it wa
tripping which turned out to be S/C line output transistor (or HOT a
some call it), probable cause being C2455 (47uF/25V) in the lin
driver circuit, low in value at 36uF. This is apparently the usua
cause with this chassis, and there is also a PSU kit available fo
the SMPS in the event that the set continually kills the line outpu
transistor
Anyway, replaced the transistor (BU4508DX) with a BU2508DF an
replaced the cap with the only available one (47uF, 63V). The set no
comes on. I don't know if it's usual behaviour for this set, but i
takes a while for the raster to appear, during which a couple o
relays click. After 2 or 3 seconds or so, the set then shuts down. I
seems the line drive is taken away when this happens, as the HT lin
rises from its value of 126V under load, to its 140V unloade
potential
Although it shuts down quickly, I found that I could keep it on longe
by going through the channels; it seems to stop the shut-down process
I brought up a channel with a very good undistorted image, stoppe
flicking through the channels, leaving it one this one, and then th
set died after a few seconds as normal. The transistor doesn't see
to be getting terribly hot during this
Incidentally, it may just be me, but the line stage doesn't soun
right... the high-pitched noise coming from the LOPT seems to hav
harmonics by the way there is a 'flicker' or 'roughness' to it. It'
hard to describe
Any ideas or suggestions would be much appreciated as this has been o
the bench too long now and I'm tired of its 32 inches taking up mos
of the workspace and falling over its gigantic rear cover
Thanks to all who even read this, and especially to anyone wh
replies
Jame
I've got a sod of a TV set here which is puzzling me and I hoped tha
someone here more knowledgable than myself might be able to offe
some advice
It uses the L01.1E chassis and is a 32" widescreen. Originally it wa
tripping which turned out to be S/C line output transistor (or HOT a
some call it), probable cause being C2455 (47uF/25V) in the lin
driver circuit, low in value at 36uF. This is apparently the usua
cause with this chassis, and there is also a PSU kit available fo
the SMPS in the event that the set continually kills the line outpu
transistor
Anyway, replaced the transistor (BU4508DX) with a BU2508DF an
replaced the cap with the only available one (47uF, 63V). The set no
comes on. I don't know if it's usual behaviour for this set, but i
takes a while for the raster to appear, during which a couple o
relays click. After 2 or 3 seconds or so, the set then shuts down. I
seems the line drive is taken away when this happens, as the HT lin
rises from its value of 126V under load, to its 140V unloade
potential
Although it shuts down quickly, I found that I could keep it on longe
by going through the channels; it seems to stop the shut-down process
I brought up a channel with a very good undistorted image, stoppe
flicking through the channels, leaving it one this one, and then th
set died after a few seconds as normal. The transistor doesn't see
to be getting terribly hot during this
Incidentally, it may just be me, but the line stage doesn't soun
right... the high-pitched noise coming from the LOPT seems to hav
harmonics by the way there is a 'flicker' or 'roughness' to it. It'
hard to describe
Any ideas or suggestions would be much appreciated as this has been o
the bench too long now and I'm tired of its 32 inches taking up mos
of the workspace and falling over its gigantic rear cover
Thanks to all who even read this, and especially to anyone wh
replies
Jame
