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565pwrdistfail [2014/03/22 15:48] n1eu |
565pwrdistfail [2015/03/26 14:19] n1eu |
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| Panasonic Aluminum Electrolytic Capacitors - Leaded 470uf 50WVDC 108C | Panasonic Aluminum Electrolytic Capacitors - Leaded 470uf 50WVDC 108C | ||
| 3 -C6,C7,C9 $0.69ea | 3 -C6,C7,C9 $0.69ea | ||
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| + | TIP(1) - Since I did not really care about the condition of the 'original' caps on the A9 board, I did a 'distructive removal' .... to make the cleaning of the PC board holes easier, and to also prevent overheating the PC board, from trying to remove the old caps (which really are just large heat sinks, when trying to unsolder them from below). | ||
| + | This is an old 'US Navy electronics repair depot' trick: To remove the 'dead/old' electrolytic caps, Without heating, Grip the body of the cap with pliers, or fingers, and bend the entire body of the cap over to the PC board. In the Electrolytic caps, like the ones on the A9 board, the internal connection to the leads is made just inside the body of the cap and break off clean.... allowing you to pull the entire capacitor body off of the remaining two mounting leads left behind, still in the PC board. These single solid wire stubs are completely easy to heat, and quicly remove, from the pc board without damaging the PC board from excess heating. Don't worry if the solder hole is clear of left over solder, that gets taken care of in the next TIP. | ||
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| + | Tip(2) After TIP(1), Heat one side of each PC board hole, with a pointed soldering iron tip that is centered on the hole. When the solder is melted, use a round (not flat) wooden toothpick, to push through all the melted solder from the opposite side of the hole. The solder does not stick to the wooden toothpick, and the toothpick tapered body displaces all the excess solder from inside the PC board hole. So, the PC hole is left open and solder free, and ready for new components to be inserted. | ||
| WB2RHM | WB2RHM | ||
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| I just replaced all 9 electrolytics on two A9 boards and would offer some advice. When you order your caps, try to obtain caps with the same true lead spacing and don't rely on bending the leads. Use a good soldering iron and solder sucker. I cranked my soldering iron to 800degF because the PCB ground plane sinks a lot of heat. Only use the solder sucker after the caps have been removed. Remove the capacitors by alternately heating each solder pad back and forth and slowly/gently rocking the cap up and out. Don't pull too hard on the caps, especially the small ones, or you will pull the cap body off and leave its leads stuck in the hole. After you remove the caps, use the solder sucker to clear the holes on all pads not connected to the ground plane. They will all clear up easily. I found it impossible to clear the ground plane pad holes so just leave them. Prep the cap leads by cutting the lead that will go through the clear hole significantly longer. Then, just position the cap with the one lead through the hole and the other shorter lead directly in contact with the clogged pad hole. Heat the pad from the opposite side of the board and gently push the cap down to insert the shorter lead. Finish soldering both leads and all caps. | I just replaced all 9 electrolytics on two A9 boards and would offer some advice. When you order your caps, try to obtain caps with the same true lead spacing and don't rely on bending the leads. Use a good soldering iron and solder sucker. I cranked my soldering iron to 800degF because the PCB ground plane sinks a lot of heat. Only use the solder sucker after the caps have been removed. Remove the capacitors by alternately heating each solder pad back and forth and slowly/gently rocking the cap up and out. Don't pull too hard on the caps, especially the small ones, or you will pull the cap body off and leave its leads stuck in the hole. After you remove the caps, use the solder sucker to clear the holes on all pads not connected to the ground plane. They will all clear up easily. I found it impossible to clear the ground plane pad holes so just leave them. Prep the cap leads by cutting the lead that will go through the clear hole significantly longer. Then, just position the cap with the one lead through the hole and the other shorter lead directly in contact with the clogged pad hole. Heat the pad from the opposite side of the board and gently push the cap down to insert the shorter lead. Finish soldering both leads and all caps. | ||
| - | Mouser part numbers for caps I selected, emphasizing low ESR and high ripple current ratings: | + | Part numbers for caps I selected, available from Mouser, emphasizing low ESR and high ripple current ratings: |
| + | C1, C2 100uF 50V 5mm lead spacing Panasonic EEU-FR1H101B (these use bent leads and it would have been slightly preferable to find a cap with straight leads) | ||
| - | N1EU | + | C3, C4, C5 10uF 50V 2.5mm lead spacing Nichicon UTT1H100MDD |
| + | C6, C7, C9 470uF 63V 5mm lead spacing Panasonic EEU-FR1J471B | ||
| + | |||
| + | C8 100uF 25V 2.5mm lead spacing Panasonic EEU-FR1E101 | ||
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| + | N1EU | ||
