Sansui AU-D5 Integrated Amplifier Repair
This amp came to me with a complaint that the protect mode is on, and all LEDs on the right channel light up.
As usual, opened the amp and did a thorough cleaning.
Since the main caps were a bit bulgy, as you can see from one of the above pictures, I checked ESRs of all the Electrolytic Caps with Blue ESR meter and found many of them out.
Even the capacitance value was far below the tolerance level. Following pictures are of 9000mfd/63V. (I replaced these with 10,000mfd/100V caps)
So decided to replace all electrolytic capacitors on the board. Changed 56 capacitors totally.
See, how the board looks after replacing the caps:
Did lubrication of all controls and switches with Philips Switching Cleaning Oil (my old stock; this is no longer available). Found that the rotating type speaker connectors were jammed. So, removed it from the amplifier, dismantled each one of them and found cut wires of the speaker inside these. This is a curse with this type of connectors!
Reconnected the Speaker outlets, and reassembled the PCBs, duly connecting all the wires and after visual examination for any possible mistakes, switched it on. It worked perfectly. So, put the covers back. Just see how it started working perfectly well:
Another satisfactory job!
This article was prepared for you by Parasuraman Subramanian from India. He is 65 years old and has more than 30 years’ experience in handling antiques equipment Valve Radio, Amps, Reel Tape Recorders and currently studying latest techs classes conduct by Kerala State Electronics Technicians’ Association. He was a BBA graduate, retired as MD of a USA company and presently working as Consultant Manager, Purchase & IT, in Irinjalakuda Cooperative Hospital.
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You may check on his previous repair article below: