I have this Sharp 37" set. An Inverter transformer was clearly burned out, and I couldnt find a replacement online.
The Sharp is unusual--as its Inverter runs from a 60 odd volts supply as opposed to the usual 24V.
My only option was to buy a complete CCFL Inverter board for it--rather expensive, no cheapies around at the moment--but as I didn't know the condition of the set otherwise, I decided some cunning messing round was needed.
First I removed the dead transformer, which had One Primary and Two Secondaries, each driving a separate tube.
--It was clear that only one Secondary was faulty--burned. (12K resistance as opposed to 1.8K for good sec.)
Using a knife and wire-cutters I removed that dead coil completely from the transformer.
My first idea was to use the remaining secondary after re-fitting, to drive the secondary of another (24V, 37") transformer and use the other secondary on this additional to run the lamp.
--This didnt work--Again 2 sec to black, not happy probably due to extra loading or leakage-inductance etc--Dunno. My guess is, loading although there shouldn't be much,--maybe 5% additional as doing this idea the transformers are acting 1:1 Perhaps some major imbalance due to the additional inductance of the add-on Tx was detected....
--The primaries seem to be wired in two strings of four transformers, supplied from the 60 odd volts....
So, I removed that and then for a larf, just cross connected the remaining good secondary to drive both CCFL tubes, attaching to the pads the dead secondary were originally, to the remaining--
Bugger worked, and has done for several hours! A good dodge just to test out a set you know nothing about.....
--Now I know with confidence a replacement complete inverter board will fix this one up properly and it'll all work nicely.
Surprisingly the transformer doesn't appear to get hotter than any other on the board and it seems to be driving both tubes as there's no dark band on the picture on white-screen....
The Sharp is unusual--as its Inverter runs from a 60 odd volts supply as opposed to the usual 24V.
My only option was to buy a complete CCFL Inverter board for it--rather expensive, no cheapies around at the moment--but as I didn't know the condition of the set otherwise, I decided some cunning messing round was needed.
First I removed the dead transformer, which had One Primary and Two Secondaries, each driving a separate tube.
--It was clear that only one Secondary was faulty--burned. (12K resistance as opposed to 1.8K for good sec.)
Using a knife and wire-cutters I removed that dead coil completely from the transformer.
My first idea was to use the remaining secondary after re-fitting, to drive the secondary of another (24V, 37") transformer and use the other secondary on this additional to run the lamp.
--This didnt work--Again 2 sec to black, not happy probably due to extra loading or leakage-inductance etc--Dunno. My guess is, loading although there shouldn't be much,--maybe 5% additional as doing this idea the transformers are acting 1:1 Perhaps some major imbalance due to the additional inductance of the add-on Tx was detected....
--The primaries seem to be wired in two strings of four transformers, supplied from the 60 odd volts....
So, I removed that and then for a larf, just cross connected the remaining good secondary to drive both CCFL tubes, attaching to the pads the dead secondary were originally, to the remaining--
Bugger worked, and has done for several hours! A good dodge just to test out a set you know nothing about.....
--Now I know with confidence a replacement complete inverter board will fix this one up properly and it'll all work nicely.
Surprisingly the transformer doesn't appear to get hotter than any other on the board and it seems to be driving both tubes as there's no dark band on the picture on white-screen....
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