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Sansui AU-2900 Recap/Restore

Zeus12

Zeus12

Active Member
Greetings Audiophiles,

Have this wonderful Sansui that I would like to do a full Recap and Restore on it. It was working great before but would like to do it, first to practice and learn and secondly, to do something and not go crazy during this so-called f******g pandemic. "The devil finds work for idle hands".:rflmao:

So far this is what I have done: The mandatory "Deoxit" treatment, face plate and chassis cleaning along with a nice luke-warm bath for the knobs and switches.
Sansui 2900 front.jpg
Sansui 2900 front 2.jpg

Here is the original F-2554 Driver Circuit board (PSU) with all ELMA caps. Could somebody tell me why there are 2 different colors, blue and gray that have the same UF and voltage? Is blue higher quality?
Sansui 2900 PSU original.jpg

Started with the PSU board and this is what I have done so far: I have changed the 2 big ones (3300 uF 50V) with Panasonics and the rest with Nichicon UPW series. From what I understand, the UPW series is great for "non-audio path" and the UFG and UES, for example, are great for "audio-path". The orange caps are low noise and should be replaced with WIMA film caps and for that matter ALL 1uFs caps.
Sansui 2900 PSU Recap and pending transistors to change.jpg

From previous posts, I understand that it is recommended to change the transistors 2SA726 with KSA992F and the 2SC1313 with KSC1845 because they are prone to noise. Is this correct? Regarding the output transistors, the Sanyos, I should leave those alone for the time being. I should also be very careful handling the transistors and always keep them on an "anti-static" surface, for example the bag in which they came in from DigiKey.

I should not start on the Tone Control Board (F-2555) until I finish the Driver/PSU board, correct? Any other suggestions?

Cheers!!!
 
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Great job sofar..
I would not exchange those transistors if there nothing wrong with them... Surely it is very straight forward but why change a winning team?

Transistors are not as prone to damage due to static electricity as IC's are but never the less, it is good to store them in the package they came in..
 
Hi MacMillan and VintageDutch,

Thank you both for your encouraging words!!

"When there is a WILL, there is a WAY!!!" :):):)

Cheers!!!:beerchug:
 
Greeting Audiophiles,

Finished recapping, (total recap) the AU-2900. The tone board was a little difficult to get to but I did it by removing the front chassis (front part). I used Panasonic, Nichicon (UPW and UKT Series) and WIMA film caps.

I have to say that it has made A BIG DIFFERENCE. The sound is cleaner, crispier and overall better separation.
The best analogy would be something similar to this: You are wearing the same clothes which you have been wearing for a couple of weeks. Now you have WASHED them, used SOFTENER, and IRONED them. Still the SAME clothes but better. Don´t know if that helps, but obviously it´s difficult to describe sound in writing.

Here are some pics:
Sansui AU-2900 pic7.jpg
Sansui AU-2900 pic9.jpg
Sansui AU-2900 pic11.jpg
Sansui AU-2900 pic13.jpg
Sansui AU-2900 pic12.jpg
Sansui AU-2900 pic1.jpg

Overall very happy with the results and worth the time put in. Besides, as I said in my first post, helped me stay out of trouble.:rflmao::rflmao:.

Cheers!!!
 
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