Defective capacitors in Actiontec powerline adapters

[flashdrive]

Hi all members:

I purchased actiontec 500 mbps homeplug adapter which works the same as yours.I been trying to figure out what the pc 3 100uf 25v, pc8 10uf 400v and pc9 1000uf 6,3v do my circuit. The cap I am really interested in is the pc8 10uf 400v? Why is their a 400v cap on this board when it also has mov to protect circuit? One of units went bad to leds and no power. Caused by defective pc9 1000uf 6.3v cap. so what does pc8 10uf 400v do in this circuit. Any engineer know how this unit uses these three caps? I spent about 20 hours on net trying find information on the Atheros ar7420 ar1540. The most I have found is basic block diagrams. I use these actiontec 500 pwr for computer at home. And after year or so the unit will go dead. I gone through 3 bad units so far. Here's the location from Tim Higgins article. Fig.4 inside shot-actiontec left and trendent right. I know replacing the defective cap fixes the unit, but like to know how they used in this circuit. Thanks for any help on actiontec product. At one time I could trace a circuit till they came out with SMD all over these mini boards.

 

[System Error Message]

Because for AC voltage, that 240V does not mean peak to peak, 240V is some sort of average as the peak to peak voltage exceeds 300V. Component ratings should always exceed the maximum the unit is going to experience.

Besides theres nothing wrong with having a large gap in voltage rating. For example if you used a bridge rectifier no reason to use one for 1000V 100A rating if it costs similarly as a 100V 10A variant.

If 3 units go bad there really must be something wrong. Take a dead unit and poke around with a multimeter. Usually the PSU is the issue not outputting a good or correct DC voltage. If you have an oscilloscope, plug the probe into the DC out of the PSU to see if the voltage out is both stable and correct.

 

[flashdrive]

Part of my problem is this circuit board is only 2"x 2" components on both sides and they are all most all SMD's. I tryed replace the defective cap 1000uf 6.3v but first I had to get out of the box, all most no room for soldering iron to unsolder Ac pins. Removed board then found out SMD's all over both sides of board. Just to replace the 1000uf 6.3v is all most impossible because of the smd's attached to positive and negative legs. So not damage board or components. As far as power supply unit I have no idea where it is on mini circuit board? I tryed googling parts not much luck on that either. 25516-1A1A1 8 pin, 1319 LNK62300 or LNK6230G 7 pin could be power regulator 7420FB.1416 4 pin. Their nothing on net about the pin out for Atheros AR7420 or AR1540. Their's a general read on these parts only. I used to enjoy working with electronics building or repairing now just pain because of all the SMD's on very very small circuit boards. The way companies look at this is their through away boards that's why all the SMD's. I would have asked sooner but had to take care of some personal problems. I usually answer with in a day. If find information on these parts please email me. Thanks.

 

[sfx2000]

DigiKey is likely your friend...

Do a search there -- https://www.digikey.com/

 

[flashdrive]

I have the capacitors to replace on unit but the smds are attached to each leg of the cap I like to replace and likely will destroy the smd part which do no even know what it is to replace it. So Digikey will not help. The part I need to replace is 1000uf 6.3V I have 1000uf 16V. These smds were probably wave soldered to this circuit board.

 

[System Error Message]

for SMD you need a SMD station. This involves a hot air gun, if you wish to learn to repair these units you should test it out on test circuits meant for you to learn SMD soldering. You can also watch Louis Rossmann on youtube as he does a lot of repair videos where he repairs laptops, phones, circuit boards.

Also capacitors arent hard to solder back if you know where they go. You know which capacitor is defective so you should know to replace it. The main problem question are the terminals on the capacitors as you have to put them in the right way if they have terminals. So if there is a + - on the capacitor you just need to match it up. One way to do this is to use a bench PSU, put a bit of voltage and a tiny bit of amps at the DC in for the circuit and measure the voltage with a voltmeter. If you see a negative voltage than you just have your meter leads the wrong way round but it should indicate to you the terminals.

In some cases the terminals are connected the other way round. If you need a schematics since you dont remember which way the capacitor was added in than you need to try asking the company, which may not always work as they like to prevent IP theft, but you can ask them for a specific area instead.