Sansui AU-505: Parts List
I have assembled a parts list for this amplifier. My restoration also touches some of original transistors. Even if I consider them irreplaceable for an authentic Sansui sound, I want to increase the lifetime of this amplifier. But mostly I am interested in exchanging the electrolytic capacitors. So this is what you will find listed below.
The schematic value corresponds to what normally can be found in the electrical schematics. The recommended value is what I replaced the former part with. The BP inscription signifies a bipolar capacitor. Where I found appropriate, I have chosen a film capacitor replacement instead of an electrolytic. My reasons are reliability in time. Less electrolytic capacitors, less time-ticking bombs.
Descriptions and Parts Listings
The Power Supply filtering capacitor is mounted on the Chassis. I have not decided to exchange this one as it tests incredibly good for its age. In order to maintain the original aspect, you need to source a fat capacitor that will fit the original metal clamp fixture.
The Equalizer and Tone Control Block is coded F-1303A and implements the Phono preamplifier and the RIAA curve corrector along the tone control circuit. This board is held in place by the axles of the potentiometers bolted to the front face. To release it for an easy access, you need to remove the black front face then release the potentiometer axle nuts. Or if you are really skilled, you can do everything with the board still in place. I have chosen not to release the board.
|C003||470 uF / 35 V||1000 uF / 50 V|
|C004||470 uF / 35 V||1000 uF / 50 V|
|C601||1 uF / 50 V||1 uF / 50 V FILM|
|C602||1 uF / 50 V||1 uF / 50 V FILM|
|C605||10 uF / 10 V||10 uF / 16 V|
|C606||10 uF / 10 V||10 uF / 16 V|
|C609||10 uF / 10 V||10 uF / 16 V|
|C610||10 uF / 10 V||10 uF / 16 V|
|C611||1 uF / 50 V||1 uF / 50 V FILM|
|C612||1 uF / 50 V||1 uF / 50 V FILM|
|C705||1 uF / 50 V||1 uF / 50 V FILM|
|C706||1 uF / 50 V||1 uF / 50 V FILM|
|C709||100 uF / 6.3 V||100 uF / 16 V|
|C710||100 uF / 6.3 V||100 uF / 16 V|
|C711||1 uF / 50 V||1 uF / 50 V FILM|
|C712||1 uF / 50 V||1 uF / 50 V FILM|
The Filter Block is coded F-2001 and is a small square board bolted directly in the steel chassis, upside down. Beware that in order to release this board, you need to undo a big solder point that doubles as a ground point. You need a really powerful soldering gun or a high temperature capable soldering station. With a 40 W soldering iron, you stand no chance. Unfortunately this board really needs to be released from its fixture or you cannot even see the electrolytic capacitors. Note that TC signifies a tantalum capacitor.
|C006||100 uF / 50 V||220 uF / 63 V|
|C007||220 uF / 25 V||470 uF / 35 V|
|C751||1 uF / 50 V||1 uF / 50 V FILM|
|C752||1 uF / 50 V||1 uF / 50 V FILM|
|C755||1 uF / 50 V TC||1 uF / 50 V FILM|
|C756||1 uF / 50 V TC||1 uF / 50 V FILM|
|C761||47 uF / 6.3 V||47 uF / 16 V|
|C762||47 uF / 6.3 V||47 uF / 16 V|
The Power Amplifier Block is coded F-1266A. This is easy to spot as it occupies most of the right of the steel chassis. It has the two black large audio-class electrolytic output capacitors. I suggest you don't change these ones, should they test OK. These days, power output coupling capacitors are not made to last. If you find a good source of coupling capacitors capable of high current then go ahead and replace them. I have not touched them. Be careful as these define the capacitor coupled Sansui sound.
|C805||1 uF / 50 V||1 uF / 50 V FILM|
|C806||1 uF / 50 V||1 uF / 50 V FILM|
|C807||470 uF / 16 V||470 uF / 25 V|
|C808||470 uF / 16 V||470 uF / 25 V|
|C809||33 uF / 16 V||33 uF / 25 V|
|C810||33 uF / 16 V||33 uF / 25 V|
|C813||47 uF / 50 V||47 uF / 63 V|
|C814||47 uF / 50 V||47 uF / 63 V|
|C815||47 uF / 6.3 V||47 uF / 16 V|
|C816||47 uF / 6.3 V||47 uF / 16 V|
|C819||1500 uF / 63 V AUDIO|
|C820||1500 uF / 63 V AUDIO|
|C822||100 uF / 75 V||220 uF / 100 V|
From an electronics point of view, this amplifier has a simple construction. It rises absolutely no problem whatsoever during the restoration process. You can observe the large number of 1 uF electrolytic capacitors that can easily be replaced by 1 uF film counterparts for a solid reliability in time.
As always, let me throw a piece of advice. Do not hurry, take your time and do the job once. And do it well.