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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 12th Nov 2022, 4:33 pm   #1
US7IGN/P
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Default Switching Power Supply problem Pioneer DVL-91

Greetings!
I hate dealing with switching power supplies, but this is the only way to understand how they work and learn how to fix them. I was asked to repair the Elite DVD player Pioneer DVL-91, which was connected to a 220 volt mains instead of 110 volts. Naturally, it burned out. I replaced bad large capacitor after the rectifier, the suppressor and a few more suspect capacitors in the primary circuit. I checked all semiconductors and capacitors in the rest of the circuit.
Then I connected it to a 220/110 volt transformer through a 100W incandescent lamp, which is constantly lit. Voltages appear on + and - 14 and - 27 volts lines on the top of the secondary circuit. Sometimes appear and disappear + and - 5.6 volts lines on the bottom of the secondary circuit. When you turn on the power supply directly to the 110V mains without an incandescent lamp, the 3,15A fuse blows.
I replaced the PC817 optocoupler and AN1431T VR and even applied signals from the generator to the windings of the transformer (which I previously dropped out) and looked at the pure sine wave on the oscilloscope at its operating frequency of 3 MHz. What could be the reason for this behavior of this power supply?
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Old 15th Nov 2022, 8:29 pm   #2
Robert Gribnau
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Default Re: Switching Power Supply problem Pioneer DVL-91

Your question is about the Pioneer DVL-91 but your attachment (which probably got resized by the forum software, so it lost detail; maybe uploading it as a pdf-file works better) shows the power supply of the Pioneer DVL-919. Do the DVL-91 and DVL-919 share the same power supply?
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Old 20th Nov 2022, 9:17 pm   #3
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Default Re: Switching Power Supply problem Pioneer DVL-91

Hello Robert and thank you for reply!
Yes, the DVL-91 and DVL-919 share the same power supply.
And I have already repaired it. The problem was in the new suppressor. I just threw it away and everything worked great. I gained a little more experience - even a new part can be bad.
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