Repairing the 7-segment LED of a Sony 5.1 sound system

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debojitacharjee

New Member
I have one Sony 5.1 sound system but its 7-segment LED display is not working properly because the numbers (volume level) are not showing up completely and all the segments don't light up. Sometimes, the whole display shows nothing at all.

I have also noted that when I turn ON and OFF the system using my remote, the LED display shows weird codes.

I need to know whether the LED driver IC (PTC 6955) is gone?

I would also like to know what the bus lines (CL, CE, DO, DI, SBY... ACF) are on the board for?

What is the connector with the labels RES, P4, VSS, PA0, and VDD for?

There is another chip HT48F50E, and could that be damaged?

The model number of the sound system is SA-WID7.

Please check the video on the link below to see the problem.


https://drive.google.com/file/d/1ZAODA4ofbmZIdgiM70HkjAqu7zD6-s_i/view

I have attached the snapshots of the chip and PCB.
 

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You have already asked the same thing here:

Fixing the 7-segment LED of Sony sound system

I have one Sony 5.1 sound system but its 7-segment LED display is not working properly because the numbers (volume level) are not showing up completely and all the segments don't light up. Sometimes, the whole display shows nothing at all. I need to know whether the LED driver IC (PTC 6955) is...
www.electro-tech-online.com
 
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But no one was able to give a solution. That's why I included a video of the problem, but no one responded to that and that's why I thought of creating a new post.
 
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On the CPU chip (on the left), what is that dark spot on the 3rd leg from the bottom right (pin 12)? Is it a burned trace?
Watching the video, it could be one of many things, but first instinct is that the CPU chip is not resetting properly on power up, just setting pins at random values. Other possibility is a bad driver chip (though some segments do randomly light up at some point, but not all), or a signal line to the CPU chip is in a bad state. Retouch all the solder joints, a cold solder joint can cause such symptoms. That also means re-touch solder joints on the other end of the cable feeding that board.
Not sure shat component CF1 is (blue thing). It might be a resonator?? There should be markings on it.
Check the voltages, the Vcc should be close to 5.0V (check at the cable input labelled +5V)
Good luck.
 
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There is nothing wrong with the 12 pin track and the black spot was there from the starting. CF1 is a ceramic filter---a kind of ceramic resonator used for the microcontroller for generating it's frequency. My guess is the driver chip is malfunctioning. What are the compatible driver chip that I can try as a replacement?
 
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What makes you think there would be any?, generally you would obtain a replacement from Sony spares.
 
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