Author Topic: Panasonic Hi-Fi SA-AKX50 Fault Capacitors replaced still the same  (Read 1722 times)

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Offline Hiixmanone

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Hi Guys I was wondering if someone can help me out.
My Panasonic Hi - Fi SA-AKX50 broke down for no reason So i decided to took it apart and have a look inside have a check on the board.
I' ve noticed one capacitor blew up 220uf 50V and one smaller is about to do the same (22uf 50V).
Yesterday I replace 4 capacitors 2x 220uf 50V and 2 small with 22uf but 100V.
Then I put whole system together and after turning on the blue ring light comes on for few seconds about 3s you can hear fan start going and then is off again so nothing changed .
Will be thankful for few advices.
My question
1. Could I make a wrong soldering capacitors into a board ?
2. Could blown up capacitor damage boar so is useless now ?
Thanks for any response off course according to the subject::...
Peace::.... 
 

Offline Psi

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Re: Panasonic Hi-Fi SA-AKX50 Fault Capacitors replaced still the same
« Reply #1 on: May 15, 2012, 08:02:57 PM »
When a device stops working entirely (and a bad capacitor is found) the bad cap is normally responsible for blowing some other stuff up. Most things will work with some bad capacitor, just not very well. (audio noise, crashing, unstable operation etc.).

If the caps are part of a switchmode powersupply then the next thing to check is the switching fet/transistor and diode. They will normally be in the same general location as the capacitor .
« Last Edit: May 15, 2012, 08:06:03 PM by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)

Offline amspire

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Re: Panasonic Hi-Fi SA-AKX50 Fault Capacitors replaced still the same
« Reply #2 on: May 15, 2012, 09:56:20 PM »
If one capacitor had exploded and a second one was about to go, then it could be a sign of overvoltage. If so, then you have to worry about what else is connected to the same capacitors.

If it helps, here is the service manual:

http://www.electronica-pt.com/images/fbfiles/files/MS_SC_AKX50LB_K_1_.pdf

A quick look and it looks like there are two switching supply circuits so I guess one is for standby power and the other is the main supply for the amplifier. If there is a fault, it could be in either supply, or something could be dragging down a supply forcing the micro to shut everything down.

Or some other random problem that again results in the micro deciding to shut down.

If you get stuck, nothing beats posting up a circuit with measured voltages on a whole lot of nodes, if that is possible. Definitely try and capture the voltage on all the major power rails before the system does shut down.

Richard.


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