Restored SONY SA-WMD40 Multimedia Speaker System Making Happy A Holidaying Customer
This Multimedia Speaker System was brought to me by a new customer, referred to by an unknown person. The complaint was that the power on through the 18V adaptor was visible, but never responded to commands from the remote or front panel control. In order to open the sub-woofer, we need to carefully pry the front wooden frame, which holds the control panel and speaker grill. I removed two front foots in order to make prying easier and made enough space to insert a minus screwdriver to force the front portion out. In these types of speaker systems, this portion might have wooden legs which get inserted into its grooves with plastic holders on the other side.
The company also uses Fevicol to making bonding tight to avoid vibrations. With a lot of careful prying using the blade of a heavy flat screw driver, I could take out the front portion without causing any damage to the wooden hard board. In the rear, the Amplifier cum power supply was housed inside a plastic case, screwed in five places. I removed this portion too. Let us now have a look at inside:
I removed the boards from behind as well as from the front and subjected the entire system for a thorough cleaning using blower, various cleaning brushes and clothes. Now Let us take a look at the various boards used in this lovely Ampli-Speaker:
Since the customer reported that the front power switch also did not respond when pressed, my suspicion was defective switches. My guess was right as I found two switches, i.e., the power switch and one of the USB play switches were dead short. These were feather touch switches, which I had in stock aplenty. I replaced all the five switches, carefully removing the sponge pads from the old switches and fixing it on the new. If we do not do this, the press switches on the front panel would not engage the switch properly. It is a sort of gap filling cum cushioning method. Then checked the LEDs and found the Bluetooth LED was also dead short. I replaced it with a Yellow one as I did not have a blue LED in stock. The other two LEDs lit up when I checked them using Analogue Multimeter in X1 range.
After this, I connected the FFSD cables and connectors after applying lubrication oils (only in the connectors and not on the FFSD cable as it might disengage the blue insert helping plastic pieces at the ends) Then applied power and noticed that all functions were working and I could play USB with a low sound output. I could not adjust the volume, as the customer did not bring the remove and there were no controls for volume on the front panel. After satisfying that the set worked very well in all modes including Bluetooth play from my mobile, I reassembled the system. While fixing the front portion, I did not use Fevicol in order to make detachment easy, but pressed the front hard enough to have a proper hold. Now just see the system working in USB and Bluetooth modes (LEDs lit up):
The customer, who worked in the Gulf had come home for celebration of Onam (a Kerala Festival) and was so happy to have got the system restored, as he could not play it as a part of celebration during Onam. I attended to this set on the same day he brought it in, keeping aside other assignments, as I felt pity that this boy could not enjoy the music on his holidays in the home.
I felt what I would do if it was my own son and responded to his desire providing immense satisfaction to him as well as to me, which got collected with additional splendor of love and care. Mission successfully accomplished without much ado, making it a good day!
This article was prepared for you by Parasuraman Subramanian from India. He is 74 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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Albert van Bemmelen
February 9, 2025 at 5:45 pm
A good and well explained repair as always dear Parasuraman.
Maybe it is me, but I always notice the word 'cum' you use in your repairs quite often? Which seems a bit odd as it gives me a different ring as opposed to repair so to speak. Or it must be my d*rty m*nd... that is a joy forever as they say?(lol)
Parasuraman S
February 9, 2025 at 11:00 pm
Ha! Ha! An unusual observation and comments! Shall take care! Many thanks, dear Albert!
Waleed Rishmawi
February 9, 2025 at 9:37 pm
Helping hands is always blessings to others. Keep up the good work my friend and be blessed
Parasuraman S
February 9, 2025 at 11:00 pm
Many thanks, dear friend!
Mark J
February 10, 2025 at 8:27 am
Parasuraman anther great repair article. Well done.
Parasuraman S
February 10, 2025 at 12:15 pm
Many thanks, dear Mark!
Yogesh Panchal
February 12, 2025 at 3:46 pm
Good Job! Sir
Parasuraman S
February 12, 2025 at 8:29 pm
Many thanks!