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diyAudio Member
Join Date: Oct 2007
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Hello!
I have a SMPS wich is normally fitted into a Pioneer plasma screen. The SMPS is on a separate PCB and made by hitachi. The first thing i replaced was R133 wich was open due to high current when Q125 shorted. Both Q125 and R133 are replaced Q125(2sk2651) R133 = 0.1ohm Brown Black Silver Gold. I also replaced Q126 with a similar device. Q119 wich is the "driver" did not have any reading when measured out of circuit so i replaced this one also. The problem is that i only have the 5V Standby Voltage wich is fed directly before rectification. It just wont start up, no smoke no nothing. The "ALARM" LED is lit as soon as i plugg in the power cable. I dont know what that means but i guess something is wrong. R362 gets quite hot but it is a high wattage resistor. One problen that i can se is that Q109 wont turn on, i just get a over and over from 0v to 0.45v cycle on the base. I really need some advice, today i took voltage readings on nearly ALL ICs. Schematic here, www.itxpress.se/433.pdf page 129 and 131. |
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