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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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#1
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B&O LX2802
Goes to black screen after short warm up (10-30 sec). Measured hor. drive,
this should be 230 Vpp but changes from ca 50 to 150 Vpp. The rate of change is 50 Hz (the same as line freq. -230v / 50Hz). Should I go for a defective line trafo ( somehow leaking?) or a defective deflection coil? Due to the low freq. of the oscillation, I don't think it's bad caps, as could be expected with high oscillation... Def. coil resistance: hor = 2.0-2.1 ohm, vert = 6.5 - 6.6 ohm Any ideas? |
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Please tell me what is a Line Trafo ?
kip |
#3
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john wrote:
Please tell me what is a Line Trafo ? LOPT --- Met vriendelijke groet, Maarten Bakker. |
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By Line trafo I mean the transformer, seperating HOT and cold circuit in the
TV. It usually have around 18 pins. 4-6 on the primary side, the rest on the secondary side. I belive bad insulation inside it could make it possible for the line power to get through somehow. Measured B+ seems like a mixture of proper B+ and power line voltage. Anyway, I'll try to swap it. Not shure if my spare is working either... "john" skrev i melding .. . Please tell me what is a Line Trafo ? kip |
#6
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Den Tue, 07 Dec 2004 18:19:36 +0100. skrev Murbolt:
Goes to black screen after short warm up (10-30 sec). Measured hor. drive, this should be 230 Vpp but changes from ca 50 to 150 Vpp. The rate of change is 50 Hz (the same as line freq. -230v / 50Hz). Should I go for a defective line trafo ( somehow leaking?) or a defective deflection coil? Due to the low freq. of the oscillation, I don't think it's bad caps, as could be expected with high oscillation... Def. coil resistance: hor = 2.0-2.1 ohm, vert = 6.5 - 6.6 ohm Any ideas? Here are the components you always change when they comes to service +4C28 (220µF/16V) +4C29 (100µF/16V) +4C34 (6.8nF/1500V) +4C32 (1.8nF) +4C32 (1.5nF) -4C35 (18nF) +4TR15 (BC369) +4TR11 (BU508A) -53C46 (100nF/63V) +-53R63 (pot 2K2) -53C48 (10nF/2.5%) -53C45 (10nF/20T) + = always - = not nesseseraly +- = depends what in from birth Further modul 04 replacements : 4C26 4C54 4TR9 4R63 4C48 4C47 4C44 4C45 4C49 4C14 shortcircuit P26-4 and P26-2 at modul 26/27 replace : C640 at modul 01/51 replace: Tr1 Tr2 Tr3 Tr11 Happy soldering -- Best whishes Christian Treldal |
#7
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Murbolt wrote:
By Line trafo I mean the transformer, seperating HOT and cold circuit in the TV. It usually have around 18 pins. 4-6 on the primary side, the rest on the secondary side. I belive bad insulation inside it could make it possible for the line power to get through somehow. Measured B+ seems like a mixture of proper B+ and power line voltage. Anyway, I'll try to swap it. Not shure if my spare is working either... This is commonly referred to as SMPS transformer or supply transformer... Line is mostly used as in line output transformer. --- Met vriendelijke groet, Maarten Bakker. |
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