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repair of Alinco DM-330MV power supply

george166

New Member
Hello,
im trying a few days now to repair one power supply from Alinco DM-330MV. It has blown one of the power transistors Q1 and one diode D8 found faulty. I have replaced a matched set of the Q1 and Q2 and searched with desoldering and checking with "Peak Atlas DCA55" all the transistors and diodes that i found. Changed for testing the TL494 and no other visible damage to the capacitors found. The secondary power supply works, so when i turn ON the power supply the leds for the instrument light are on and the FAULT led is ON too. But of course no power output. Please because im getting crazy, i have fixed some smps with quite success, but in this my brain is getting crazy. Can you give me some help please?
Im attaching the schematic
Please, any help accepted
 

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Could you please provide guidance on a recommended course of action that I can pursue? I have previously addressed the issue of high voltage occurring before to the Q1-Q2 stage.
Hello,
im trying a few days now to repair one power supply from Alinco DM-330MV. It has blown one of the power transistors Q1 and one diode D8 found faulty. I have replaced a matched set of the Q1 and Q2 and searched with desoldering and checking with "Peak Atlas DCA55" all the transistors and diodes that i found. Changed for testing the TL494 and no other visible damage to the capacitors found. The secondary power supply works, so when i turn ON the power supply the leds for the instrument light are on and the FAULT led is ON too. But of course no power output. Please because im getting crazy, i have fixed some smps with quite success, but in this my brain is getting crazy. Can you give me some help please? Im attaching the schematic
Please, any help accepted
 

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