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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Philips TV -- dual schottky
Model number is 19pfl3403 (a real dog I understand) -- anyway, not getting 5.2v but around 4.
I'm not a repair guy but electronics is my life and looks like it may be the dual schottky rectifier -- good AC voltage out of the transformer. part is a 60v 10a dual -- wonder if a 45v part will suffice? (it's what I have). after all they're using a 100v schottky for the 13v supply so it sounds like it'll work. THANKS if you know off hand. |
#2
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Philips TV -- dual schottky
"mkr5000" wrote in message news:3111226.55.1321981106144.JavaMail.geo-discussion-forums@yqie15... Model number is 19pfl3403 (a real dog I understand) -- anyway, not getting 5.2v but around 4. I'm not a repair guy but electronics is my life and looks like it may be the dual schottky rectifier -- good AC voltage out of the transformer. part is a 60v 10a dual -- wonder if a 45v part will suffice? (it's what I have). after all they're using a 100v schottky for the 13v supply so it sounds like it'll work. THANKS if you know off hand. It's a bit unusual for diodes - even Schottkies - to go 'weird'. Commonly, they fail short circuit. I would have thought that a far more likely cause of your low voltage, is the filter cap following the rectifier. If that goes open or high ESR, you will get a low reading of the DC volts that you're expecting, the reason being that if you look at the voltage across the cap with a 'scope, it will be hashy not pure DC, so the average that the meter tries to make of it, will be lower. It is very very common for filter caps following Schottky diodes in SMPs, to fail in this way. Arfa |
#3
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Philips TV -- dual schottky
"Arfa Daily" wrote in message ... "mkr5000" wrote in message news:3111226.55.1321981106144.JavaMail.geo-discussion-forums@yqie15... Model number is 19pfl3403 (a real dog I understand) -- anyway, not getting 5.2v but around 4. I'm not a repair guy but electronics is my life and looks like it may be the dual schottky rectifier -- good AC voltage out of the transformer. part is a 60v 10a dual -- wonder if a 45v part will suffice? (it's what I have). after all they're using a 100v schottky for the 13v supply so it sounds like it'll work. THANKS if you know off hand. It's a bit unusual for diodes - even Schottkies - to go 'weird'. Commonly, they fail short circuit. I would have thought that a far more likely cause of your low voltage, is the filter cap following the rectifier. If that goes open or high ESR, you will get a low reading of the DC volts that you're expecting, the reason being that if you look at the voltage across the cap with a 'scope, it will be hashy not pure DC, so the average that the meter tries to make of it, will be lower. It is very very common for filter caps following Schottky diodes in SMPs, to fail in this way. Arfa Its also worth remembering that Shottky-barrier rectifiers have higher junction capacitance - I usually fortify the replacement electrolytic with a mylar or polycarbonate at least 1uF. |
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