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Micro Switch Found Short In Sony Car Stereo

By Jestine Yong on September 8, 2020

MAKE AND MODEL: Sony Car Stereo Model CDX-GT44U

COMPLAINT REPORTED: None of the switches in the front panel work.

TROUBLESHOOTING AND RECTIFICATION DONE: Opened, dismantled the CD assembly and cleaned the set thoroughly. The design of this device was superb! Not strip wires! Dismantling was also very easy. Front panel, as we all might already know, can be slid out. Push the side locks and just slide the outer cover out through the rear side. Unscrew the top; remove the CD Unit after unscrewing from bottom. There you are, you can have a clear look of the inside. Unscrew the board from bottom. That’s all! You are ready for the trouble shooting.

Dismantled the front panel, by removing the PCB holding screws. Checked each micro switch for short and found Switch No.LSW911 short. This has a built-in LED. Though I tried giving a hard push inside to release the short, it did not work. So replacement was the only way. Checked with my friends for the original replacement and got one. Removed the SMD microswitch by hot air gun, adjusting the heat and air so as not to spoil the PCB or surrounding compounds. I also used a tin sheet after making a suitable opening in the middle which I placed on the switch before I used the hot air. This mask was to prevent the heat spoiling the display. Soldered the new micro switch. Placed the panel in its locking connector, applied power and found that all controls were working now. Unfortunately, the colour of the LED Micro Switch was blue instead of Red. A mistake done by my friend, who gave the part! Anyhow, I told the customer about this, and he did not mind it, which saved repeat of the removal which could have caused damage to the board.

Generally, I do not like the small Aluminium Electrolytic Capacitors used in such sets, as these have short lives. So checked the ESRs of a few and found that almost all of them were bad. So, wrote down the numbers of these capacitors and the value/voltage on a sheet of paper and rechecked to make sure that I did not make any mistakes. Plucked all the capacitors from the board using a player. (This is a delicate work, which needs some practice. The method is; hold the capacitor from the top, press it down gently and then shake it sideways not to rip off the tracks; not on the sides where these are soldered underneath. After a few shakes the capacitor will break away from its legs and come off easily.) Then replaced with ordinary capacitors and whenever the size was larger, I bent it down for proper seating. As these are to be mounted from the top, I cut the leads just enough for easy view to apply solder from the sides. Removed the tuner section, opened its case and replaced the cap in that too. After thoroughly cleaning the board, loaded the front panel, applied power and found that it was working very well! All the functions were also working. Placed the CD Unit on top and tried that too and found it to be working very well. I was relieved to see that the set was working very well in all respects. So, assembled the boards back and fixed the covers. Once again tried the set for several hours and it worked very well. Mission accomplished and intense satisfaction got added!

HERE ARE SOME PICTURES:

LINK FOR DOWNLOADING SERVICE MANUAL:
https://elektrotanya.com/sony_cdx-gt40u_gt40uw_gt44u_gt45u_gt47ue_989321401_ver.1.0.pdf/download.html

This article was prepared for you by Parasuraman Subramanian from India. He is 70 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.

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You may check on his previous repair article below:

https://jestineyong.com/burst-x-type-capacitor-caused-tv-go-dead-in-philips-crt-tv/

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14 Comments

Paris Azis

September 8, 2020 at 7:58 pm

Nice job, Parasuraman. Thank you for sharing the tip for the smd caps removal (although I knew that long ago, thanks to a very good Canadian technician I saw in YouTube, who presented the method).

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- Parasuraman S
  
  September 9, 2020 at 9:58 pm
  
  Many thanks! I too have seen that video. I learnt it from there. I remember to have quoted about it one of my previous articles dealing with repair of a monitor.
  
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- Saqib Sami
  
  September 12, 2020 at 6:14 am
  
  Please share video his youtube channel name or youtube video link.
  
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  Reply
  - Parasuraman S
    
    September 14, 2020 at 12:28 am
    
    Please search for it in google. It is very easy that way!
    
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Albert van Bemmelen

September 9, 2020 at 1:02 am

The supercapacitorman came and saved yet another device as if it was nothing! (lol). Maybe those car stereo sets always use bad capacitors that have a bad ESR from day one already when they were mounted on the printed circuit board?

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- Parasuraman S
  
  September 9, 2020 at 10:01 pm
  
  Many thanks! Yes, I too dislike these aluminium caps without any covering. I have found these to be trouble makers and if possible, I always replace these.
  
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Humberto

September 9, 2020 at 12:02 pm

Thanks for sharing your expertises. Keep on

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- Parasuraman S
  
  September 9, 2020 at 10:01 pm
  
  Many thanks!
  
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Bobby Y

September 9, 2020 at 12:58 pm

Thanks man for the tip and idea. Very helpful. BTW do you have suggestions on how can I improve the sound of an ALPINE 7279ES car stereo? This is an 80's unit, the treble seem to be not good but the bass is ok, Alpine is known as BASSHEAD units but maybe there is something that can solve my inquiry. Keep on sharing your expertise. Thanks again. Greetings.

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- Parasuraman S
  
  September 9, 2020 at 10:03 pm
  
  Many thanks! Look for any faulty component in the treble circuit. Try replacing the variable pot, if found noisy or breaking contacts or value increased beyond the specification.
  
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Yogesh Panchal

September 9, 2020 at 4:05 pm

Good job! Sir,
Care should be taken while Plucking Capacitors it works only on Good quality PCB or it may damage the PCB by tearing down traces underneath.

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- Parasuraman S
  
  September 9, 2020 at 10:05 pm
  
  Yes, I do agree. While shaking the caps, we have to observe whether it is shaking the base fitting too! But by experience, we can do it. You will be surprised to know that sometimes the caps come off by itself! That will be the condition of dry solder on it!
  
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Randika Jayasekara

September 20, 2020 at 2:11 pm

Sir,

Could you please suggestion of durable capacitor brand?

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Faizan Hameed

June 2, 2021 at 7:42 pm

sir i have CDX-G1001U model system , one night working condition off , but next day system not on , please help me .

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