Author Topic: Power supply blew cap after recap  (Read 491 times)

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Offline matt.zepess@gmail.comTopic starter

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Power supply blew cap after recap
« on: August 15, 2023, 08:21:38 pm »
This pertains to a Sony laserdisc player specifically the mdp-550, I got no power, noticed a leaking cap and 3 diodes on the dc voltage side but close to the ac circuitry, recapped and replaced the 3 diodes, turned on once again and ran for maybe 30 seconds before a poof and some smoke. This time on the end of the dc side a cap exploded from the top appears I didn’t cross anything and the caps in the right orientation, what can be causing this? I wouldn’t expect heat as it’s only 30 seconds before failure. Maybe orientation on the board itself is wrong? I thought I checked but I also got a little side tracked. I do still have some of the old ones with the same value to try if nothing else. Part was obsolete on Digi-Key not sure if these things fail like this from simply being defective.
 

Offline CountChocula

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Re: Power supply blew cap after recap
« Reply #1 on: August 15, 2023, 08:43:31 pm »
Could be incorrect orientation (could be marked wrong on the board as well—it happens, but unlikely), incorrect cap voltage, or perhaps a short that's drawing too much current. What's the designator of the capacitor in the schematic?


—CC
Lab is where your DMM is.
 

Offline 807

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Re: Power supply blew cap after recap
« Reply #2 on: August 17, 2023, 09:53:32 am »
Just for clarity. You changed a leaking capacitor in one location, but then a different capacitor blew at another location. Is that right? You also changed 3 diodes. Why was that? Did you change them for the exact same types, as you say that the part was obsolete on Digi-key?

Can you take photos of the board? Perhaps some circuit references of the components you changed would help, as the schematics are available online.
« Last Edit: August 17, 2023, 09:56:33 am by 807 »
 


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