A Shorted Surround Sound Amplifier Repaired
A friend of mine who is a repair technician contacted me about a surround sound amplifier that he encountered but he does not have any kind of repair experience in such devices.
The technician went further in the explanation about the device; it was powering on but the there was no sound coming out. It was sent to someone else for repair but instead the device was returned to customer dead.
The customer showed up to my shop and he was very upset and kindly asked me to take a look and see what I can do to help out.
As I took the top cover off, I saw this disaster on board. If you see the area where it is marked, all these capacitors in that area were exposed to high temperature and they were melted.
If you look to the back of the heat sink, you would see two missing power transistors which were taking off board by me because they were shorted. Part Number A1941 and C5198.
Please click here or the above photo to access the transistors datasheet
I do not know why these parts were exposed to high temperature but it was time to get this device fixed and send back to the customer.
As you can see in the photo, all the melted capacitors were replaced along with the two power transistors and hopped for the best.
I also took the big main capacitors off board and cleaned that silicon beneath them because that stuff was dry and conductive; it could cause damage to the device.
After all that long hours of work replacing parts, cleaning up the device, I powered up the device using a current limiter and everything seems to be smooth as expected.
The customer came to pick up the device and he brought all the speakers with him which I connected to the amplifier for a sound check. The customer and I were happy with the result and to that I could say
Mission accomplished
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.
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Note: You can check his previous article on Turkish Welding Machine Repaired
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Albert van Bemmelen
October 13, 2021 at 5:09 pm
I guess that high temperature could have been the cause of the melted capacitors. But also poor quality e-caps and deterioration in time can do the same.
Waleed Rishmawi
October 15, 2021 at 4:27 pm
Albert: no really. as I understood from the customer that the techinican used heat on the device and end up melting the capaictor. later on the output transformers were shorted as well. have a good day
Bernie Scott
October 13, 2021 at 9:14 pm
Good job...this kind of stuff happens when people who do not have the proper knowledge and skills try to fix electronic equipment....sometimes they luck into it but most of the time they cause more damage in the long run.....
Waleed Rishmawi
October 15, 2021 at 4:28 pm
Bernie: thanks man. you are right and that is so sad to see in this field. have a good and blessed day
Babu M S
October 13, 2021 at 10:05 pm
Fantastic job.Saved the amplifier and avoided e waste. Thank you very much for sharing.
Waleed Rishmawi
October 15, 2021 at 4:29 pm
Babu: you are most welcome. have a blessed day
Jai Etwaroo
October 14, 2021 at 10:14 am
Great job Waleed.
Waleed Rishmawi
October 15, 2021 at 4:30 pm
Jai: thanks man. have a blessed day
Parasuraman S
October 14, 2021 at 11:17 am
Excellent mission accomplished, accepting the challenge posed by tampering half-cooked technicians.
Waleed Rishmawi
October 15, 2021 at 4:30 pm
Parasuraman: thanks man. indeed. have a blessed day
Yogesh Panchal
October 14, 2021 at 3:38 pm
Good Job! Waleed,
Waleed Rishmawi
October 15, 2021 at 4:31 pm
Yogesh: thanks man. have a blessed day
jai Etwaroo
November 20, 2021 at 8:47 pm
Good job Waleed.