Sansui Au417: Cut bait?

02County

AK Member
I recently acquired an AU-417 amp, part of a series of components that were the shop system at a local specialty garage. Got it for a hundy, along with tuner, eq, and tape deck. I was stoked.

Brought it home, played it somewhat loudly, blew a fuse. Brought it to a local tech. $40 diagnosis says it's a bad channel. He wants $210 to fix it. He also said he thought it had been in a fire based on the dirty interior but I suspect that is instead exhaust and grease from the garage where it spent the past 30 plus years. Ill add that it did not blow a fuse during actual play time - I turned the volume down, turned it off, then returned later to play it and found it dead.

Anyway, it sounded sweet while it lasted. My question is whether the additional investment is worth it or if i should instead simply cut bait and move on.
 
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Not hard if you are as good as super' :banana:

A wonderfully generous offer to fix it for you :yes:
 
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It is indeed. I continue to be impressed by the generosity and plain out helpfulness of the AK community. And will pass it along when I can!
 
And the rebuild/upgrade begins!
It arrived in great shape.
 

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More Pics as the covers come off ....
This amp spent a life in an automotive shop, considering the environment its really fairly clean.

At a Glance:
  • One driver board was repaired in the past and certainly took some heat.
  • The other driver board has a cooked trim pot.
  • Sansui Death glue
  • Caps that leaked out
 

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And of course more.
 

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Glad to hear it arrived in decent shape and great photos. Don't like the look of some of those boards at all - some of those big black caps look absolutely cooked. Hope the prognosis isn't too grim and thank you! :thmbsp::thmbsp::thmbsp:
 
It will sing like new or better when I am done. The one driver board had some serious burning on it in the past and was repaired by someone. They left the original fuse resistors in place and did not remove the corrosive glue. The emitter resistors and outputs were also changed. Ill go through the entire unit so wont be an issue in the future.
 
Tore down one driver board tonight F-2721. This was the previously toasted and repaired and charred one. Both outputs were toast as was TR09 and all of the caps were beyond bad. The 470uF measured 332nF yep nano Farads. Here are a few shots of the burn/scorch marks cleaned off the boards and the components and the acidic glue removed. The emitter resistors were ok but the previous repair "artist" used carbon comp resistors which are swollen and also bad. More to come but it should be great with the usual rebuild/upgrade. New caps, transitors and bourns pots etc.
 

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I test every resistor in cases like this and replace diodes out of habit especially the Zeners ZD01/ZD02. Found a few out of spec resistors and 2 completely open. New caps installed and ready for the rest of new goodies coming from Mouser tomorrow.
 

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Refreshing!

If you want to ship it and pay for parts ill fix it for free. :)
PM me if you want.

I haven't been around here for that long but this has got to be the best random act of generosity I've ever witnessed on AK.

One would hope that your positive karma will be repaid to you tenfold throughout your travels in life but the beauty is that the act of giving is a reward in itself, karma at its best...but I suspect you already knew that.

Looking forward to seeing how everything turns out.
 
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