Funny Tuner IC Complaint Found In SONY Car CD Player
This Car CD /Tuner/USB Player was brought to me by a new customer with a complaint that all functions work except Radio. The complaint was confirmed on my checkup. So, I opened up the set and dismantled the boards. Located the IC handling the tuner section, which was on a separate board vertically fit.
As you can see from the picture, this set used TDA7706S, an SMD Tuner IC. (For the those who might be conscious of language: I use ‘an’ in place of ‘a’ whenever pronunciation of the following word starts with a vowel. According to Wren and Martin, quoted by my School Teachers, one should use ‘AN’ under these conditions: – “A, E, I, O, U with W and Y, when they do not begin a syllable.” ‘An’ rhymes well with SMD instead of an ‘A!’ )
Having dismantled the PCBs from the case, it is very difficult to power up for checking, without attaching the Front Control Panel. So, I attached it manually, using Rubber Bands, as you can see from the following pictures:
Checked and found that the DC voltages were present on the tuner IC. Those who are interested to see the datasheet can do so from the link TDA7706 Datasheet(PDF) – STMicroelectronics (alldatasheet.com) The crystal was checked and found to be ok both by voltages as well as wave form in the oscilloscope. The possible cause could only be the Tuner IC, which was not available in the market. The online search showed a prohibitively high price for the IC. When I shared my experience with my Techie Friends, one who had handled this particular model said that he found this IC working after heating, but might go back to ‘slumber’ when not in use for a long time.
He asked me to try heating up the IC. I used my SMD rework station and heated up the IC to a safe level. Then when I applied power, the Tuner section was working in AM/FM mode very well! What kind of a defect is this in an IC!!! After I shared the result, many others also shared their similar experiences stating that this was the same problem in this model of Sony! Perhaps a manufacturing defect or something else unknown to us. Anyhow, I switched it off and switched it on after an hour and found the Tuner was working. It was working in the next day also. So, fixed the set back and delivered it to the customer, charging only very nominally to cover the cost of service. I told the customer that if he leaves the Car Stereo Off for a long time, he would face the same problem again. Could I have kept a heat zinc on top of the IC, extended from the Audio Power Amp IC? Well, I should try it next time! (LOL)) Anyhow, this looked like a very funny solution to fix a defect!
Nevertheless, the satisfaction did not find any excuse not to jump into its collection bag! (Sorry, I forgot to click the set when it was working in Tuner mode! My apologies!) Following pictures are that of CD/USB Modes. The front panel changes the display colour in sequence, something that could be distracting and irritant to the driver of the Car. I do not know why Sony made a Car CD Player in this way, though I agree that there could be an option to switch off!
This article was prepared for you by Parasuraman Subramanian from India. He is 71 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/bulgy-capacitors-found-in-enhance-model-computer-smps/
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21 Comments
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Yogesh Panchal
March 4, 2021 at 4:30 pm
Nothing But Dry solder of the IC well done! Sir
Parasuraman S
March 5, 2021 at 9:16 pm
It cannot be. Because other technicians told me that this IC returns to defective condition on cooling! Anyhow, many thanks for your comments!
Mohamed Sittiq M
March 4, 2021 at 6:11 pm
Dear Sir,
This type problem accured in winter season.
Thanks
Mohamed Sittiq M
Parasuraman S
March 5, 2021 at 9:16 pm
Many thanks! Yes, it can!
tino
March 4, 2021 at 10:47 pm
phenomenal experience dear
Parasuraman S
March 5, 2021 at 9:17 pm
Many thanks!
Babu M S
March 4, 2021 at 10:51 pm
This is very good information about ic complaint.Thanks for sharing.
Parasuraman S
March 5, 2021 at 9:17 pm
Many thanks!
Henrique J. G. Ulbrich
March 4, 2021 at 10:53 pm
Thanks for sharing, Parasuraman. It´s a bit amazing: generally electronic components are destroyed after warming them after a certain point. And they don´t work anymore. What you reported is exactly the opposite! Each day a new knowledge. Our learning never stops!
Parasuraman S
March 5, 2021 at 9:19 pm
But the IC itself is soldered in high temperature. I just heated it up enough, but ensuring it does not reach solder melting point. Many thanks for your comments!
Albert van Bemmelen
March 5, 2021 at 1:48 am
Thanks for sharing. Sony was a well known manufacturer in those days. But they also did make terrible products too! Like a cassette recorder deck with a warning in the instruction manual never to keep the recorder heads up onto the capstan wheel and switch the deck off. That way the motor flywheel would stop and you had to open the deck just to give the capstan wheel a push to get the motor going again! (For insiders: It was a terribly made TC-FX20 cassette deck). Now the best known manufacturer probably is Samsung. And they already also made bad LCD television sets that were mentioned on forums to be unfixable! And do not forget the Smartphone debacle! So, I am just saying that it is not at all just about bad Chinese products!
Parasuraman S
March 5, 2021 at 9:20 pm
A lot of information has been shared! Many thanks for your comments and feed back!
Waleed Rishmawi
March 5, 2021 at 8:21 pm
thanks for sharing the repair experience with us as well as the grammar lesson. I really got a kick out of that and made my day brighter. have a blessed day my friend. I really love to read and enjoy your articles. keep up the good work
Parasuraman S
March 5, 2021 at 9:21 pm
Many thanks, dear! You are very unique and I read and enjoy your comments with warmth!
Imoudu Onwumah
March 6, 2021 at 12:40 am
Hi Chapman! I was reading one of your articles of 2017, where you hinted about technicians'whatsap forum. Is it open for anyone to join and how do I join if I want to ?
Parasuraman S
March 6, 2021 at 12:00 pm
Well, I am a member of a few groups locally and globally. Only known and trusted people are added by the Admins of the groups. I was recommended by my friends and got added. No other posts except technical advice, suggestions and discussion are allowed in those groups. Let me check with the admins and revert. You shall receive communication, if positive only, through our Jestine Yong, provided it has his consent. Many thanks!
Lynn Blakely
March 7, 2021 at 1:14 am
Good job Parasuraman: I have watched an apple repairman on You Tube that some times he re flows the chip. His name is Louis Rossman, he has over 1.5 million subscribers. He sometimes uses bad language but he is very quaified to repair.Think about what happens when something that is heated then it works, then when it cools it shrinks, which could indicate a bad connection on one or more of the pins on the chip.
Parasuraman S
March 7, 2021 at 2:51 pm
Many thanks for your comments and feedback. I shall search for it.
JJ
March 9, 2021 at 4:09 am
.” ‘An’ rhymes well with SMD instead of an ‘A!’ Combination of good tutorial and humour.
Parasuraman S
March 9, 2021 at 9:29 pm
Many thanks!
Daniel Luis Mihalyi
October 21, 2022 at 7:04 am
Hola
Mí nombre es Daniel, tengo en reparación un Autoestéreo SONY CDX-GT620UI, el defecto que tiene es que la radio funciona, sintoniza, pero no emite sonido de salida, el USB y el CD funcionan perfectamente
Tiene la placa de radio en posición vertical con el TDA7706
Estuve leyendo lo publicado pero no interpreto si es que la radio no encendía o si le aplicó calor al IC para que comenzara a funcionar, no sé si es el mismo defecto
Saludos
Daniel
=====================
Hello
My name is Daniel, I have a SONY CDX-GT620UI Car Stereo under repair, the defect it has is that the radio works, it tunes, but it does not output sound, the USB and the CD work perfectly
Have the radio board in a vertical position with the TDA7706
I was reading what was published but I do not interpret if the radio did not turn on or if it applied heat to the IC so that it started to work, I do not know if it is the same defect
Cheers
Daniel