Just won a new old stock Sansui AU alpha 707DR... Can I turn it on?

[Kuja]

Hello everybody.

I just won this auction:
http://cgi.ebay.ch/ws/eBayISAPI.dll?ViewItem&item=290225231298

The seller says that this AU alpha 707DR amplifier is 100% new and never used and that he opened the original box just to take pictues.

This amp was manufactured around 1990-92.
So it is some 16-18 years old.

What can I expect when I turn it on after all this time?

Could its caps be all dried out?

I did a total recap on my vintage Kenwood KA-907 from 1979.

But if this Sansui is new and never used, it woud be a shame to rip all those fancy caps out (I heard that Sansui used only highest quality parts in those models) in order to replace them with new ones.
On the other hand, they might just look pretty on the outside, while being all dried out inside.

Does anybody have a service manual for this beast?
...Or knows how and where to check an set bias and how to adjust DC offset?! What are the original bias values?

Thanks in advance!

Aleksandar

 

[aurche]

Aleksandre, If you don't have any problems with it, why should you change the caps? I have an Russian Estonia Hi-Fi Amplifier and Preamplifier. It has no electrolite caps on its sound path, but it has several ones on its sturdy protections (DC in output, current, heat, input level ....). And this year I changed them, because the protection started to kick in at higher sound levels and at the end totally stoped the amp. I replased them with Nichicons. No problem now The amp weighs almost 15 kilos and it's 2x50W with a 450VA toroid and big heatsinks (never gets hot, even warm). I think it is been built around 1987-8. This sansui is a great amp!!! I wish you luck and no problems!!!

Stefan Jordanov

 

[woody]

The caps verry well may have gonne bad over the years. If
you have a variac I would use it slowely raising the voltage
from 0v ac to your rated line voltage over a period of a couple
of hours while watching the current drawn by the amp.

Or at the verry least power it up for only a moment then power
off if you didn't blow a fuse power up again just a little longer
turn it off. With power off check with your hand if any of the caps have started to heat up. Repeat a couple of times working up to having it powered up a min. or 2 if the caps don't start to overheat you are probably ok. Then leave it on for a while.
This is not the best way to reform caps but I have used it in a few cases with old amps that had been out of service for a long time.

 

[jaycee]

Use a bulb in series with the live wire. If theres a fault, it'll glow brightly.. it'll also limit the inrush current and allow the capacitors to reform with less stress