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Fuse /Power supply troubleshooting

gio_dude

My friend at work built a 3d printer from a kit and his power supply went out. He said it made a pop noise and got no power from it. He ordered a new one already and gave me the old one and I would like to try and fix it.

 

Once I took it apart the first thing i saw was a fuse that looked blown. I got no continuity on the fuse from my multimeter. I unsoldered the fuse and the writing on it looks to be P5AL 250v or F5AL 250v.

 

1) is there anything else you guys can recommend me testing or looking for.

 

2) I found this on amazon it looks to be the right fuse but can I solder leads to it.

https://www.amazon.com/BUSHIBU-F5AL-Fast-Blow-Glass-Fuses/dp/B01NAQH2TB/ref=sr_1_2?s=industrial&ie=UTF8&qid=1496014763&sr=1-2&keywords=F5AL+250v

 

3) do you think I can put a holder on the PCB incase it blows again it would be easier to change. I attached a picture of where it was on the PCB.

 

imageimageimage

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  • Hi Giovanni,

     

    If you want to solder leads on the new fuse here is a procedure that I have used. File each end of the new fuse so you can see brass. This makes the solder adhere better. Use a hot iron and place the solder quickly on each end so that heat doesn't have time to damage the fuse element. Now tin the end of the lead wire you want to use and place it against the tinned end of the new fuse and quickly solder it. Too much time and the fuse element will melt. Do the same procedure to the other end of the fuse.

     

    Before you test the power supply it is a good idea to use an Ohmmeter and check out the bridge rectifier for shorts. The fuse you are showing has blown aggressively under high current. This is evidenced by the burn inside the glass. This is usually caused by a failure in the circuit itself. The Black Bridge rectifier is the first potential failure area. All the diodes should show conduction in one direction and very high ohms in the other. Also check the other semiconductors on the board for shorts between their Drains and Sources or Collectors and Emitters before you plug it in and power it up.

     

    It is very unlikely that the fuse is the only problem on this board.

     

    Use extreme caution as this board has lethal voltage on many of the parts.

     

    John

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  • Hi Giovanni,

     

    If you want to solder leads on the new fuse here is a procedure that I have used. File each end of the new fuse so you can see brass. This makes the solder adhere better. Use a hot iron and place the solder quickly on each end so that heat doesn't have time to damage the fuse element. Now tin the end of the lead wire you want to use and place it against the tinned end of the new fuse and quickly solder it. Too much time and the fuse element will melt. Do the same procedure to the other end of the fuse.

     

    Before you test the power supply it is a good idea to use an Ohmmeter and check out the bridge rectifier for shorts. The fuse you are showing has blown aggressively under high current. This is evidenced by the burn inside the glass. This is usually caused by a failure in the circuit itself. The Black Bridge rectifier is the first potential failure area. All the diodes should show conduction in one direction and very high ohms in the other. Also check the other semiconductors on the board for shorts between their Drains and Sources or Collectors and Emitters before you plug it in and power it up.

     

    It is very unlikely that the fuse is the only problem on this board.

     

    Use extreme caution as this board has lethal voltage on many of the parts.

     

    John

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