Power Circuit Board and Diodes

This weekend my wife and I were watching a DVD and suddently we heard a pop and the TV went blank. I replaced the 1.6A fuse and immediately blew another one. I tested all the diodes on the power board by reversing ohmeter leads and found 5 or 6 good ones and 7 bad ones. Of the bad ones, 4 are small and near the fuse so I assume they are a rectifier bridge. Two others are up off the PCB and near a transformer; one of these is larger and the other MUCH larger. The

7th one is small (like the first 4) and right next to a tiny chip.

1) Will a good diode ever test bad by this method as a result of still being in the circuit? (I did not lift one leg for any of these tests.)

2) If I remove the 7 diodes that tested bad, will a parts house be able to identify the appropriate replacement from markings on the diode itself?

3) If I successfully replace these without damaging any other components, what is the likelyhood that all the other components are ok? High? 50/50? Low?

PS, I know that DVD players are cheap these days but I like DIY projects, plus I hate to throw stuff in the landfill if it can be fixed without too much trouble or expense.

-- Bob Simon remove both "x"s from domain for private replies

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Bob Simon
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Thanks.

No it was the DVD that died. Toshiba SD-2900KU. PCB: PM0004503010; PC-POWER-K510.

-- Bob Simon remove both "x"s from domain for private replies

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Bob Simon
1, yes a good diode can test bad in circuit due to other shorts, you can clip one side of the diode and test it out of circuit with one leg still attached (power off of course)

2 is this a switching power supply? you can probably use generic diodes or bay another bad unit off ebay for parts

3 probably something bad in the power supply, maybe more than just the diodes though

Mark

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Mark

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