Excellent. Thanks.
Leestereo's Restoration & Upgrade of a Sansui AU-517
Excellent. Thanks.
Ok I’m all in now. The (almost) full tear down was a great suggestion @Jefft91. Considerably better work experience. And yes the chassis will be super tidy now, too. I ended up drilling out the plastic rivets from the outside. @Scott Muni thanks for the rivets link.
Now to depopulate and deglue.
Now to depopulate and deglue.
Jefft91
Active Member
If I'm not mistaken, the 117-417 don't have the pre/main switch on the back of the amp. If you haven't dealt with this switch before, there was a recent thread that talked about cleaning the switch in detail (among other things that you already know about): https://audiokarma.org/forums/index.php?posts/16725252/
Ah yes. Thanks. On the list! I have yet to dissect and service a switch - just topical application of cleaners previously. This seems look a good time start. And I do have a second AU-517 here for parts if things don’t go as planned.
Jefft91
Active Member
This switch is, I believe, silver plated, which turns black and fails on most units, causing channel dropout. It's not possible (or extremely difficult) to get contact cleaner inside, thus the disassembly procedure . The sliding contacts are fragile, so go easy on them. The thread covers the range of approaches to clean.
Oh yes I am on it. I ordered some jewelry cleaner which I've read @Hyperion and others using. I own pretty much every Caig product, but want to try the jewelry cleaner on this one. Sounds like a good puzzle. More fun ahead. I'll post some details once I get through it.
The other deep control cleaning I haven't enganged is the volume pot. I won't tear down the AU-517, but I will dig into the AU-717/919 and X-1 once I get there. I've seen some cool and inspiring volume pot rehabs from @ARGOU and others. Looks like another fun adventure in restoration.
Scott Muni
Well-Known Member
One advantage of using the liquid jewelry cleaner is that you don't necessarily need to dismantle switches to get them clean - remove the switches from the board, degrease them, and then use the cleaner - it has worked well for me without the worry of possibly damaging the switches. 
Be careful with those fibre pens, the fine glass strands break off and are so light they float in the air allowing you to breathe them in - best to use a mask.
Sui-Yogi
Super Member
Good luck with the restoration !
Just a thought....
Since you have disassemble the whole unit , before you take your last dessision about opening the volume pot just get the pot in your hand and shake it a little near to your ear , if the plastic stopper is broken you will hear it banging/floating in the enclosure ..... if so, I strongly recoment you open it and remove the broken pice and make a new stopper .
Had a few minutes and curiosity got the best of me. Prepped the F-2670 and opened up the switch. Some tarnish but not too bad.
Excellent advice. I’ll perform that inspection this morning.
Excellent advice. I’ll perform that inspection this morning.
F-2673 Tone Control CB
A little more progress tonight. Having these boards completely out of the chassis sure increases the efficiency and the fun. Everything according to plan here. Mods applied. "M" diode sets built. Component removal/install went well. NO GLUE. Cleaned all of the controls. Cracked open and applied some F5 to the Alps. I'll tear one completely down on an upcoming restoration. This one turns smooth and nothing loose internally.
A little more progress tonight. Having these boards completely out of the chassis sure increases the efficiency and the fun. Everything according to plan here. Mods applied. "M" diode sets built. Component removal/install went well. NO GLUE. Cleaned all of the controls. Cracked open and applied some F5 to the Alps. I'll tear one completely down on an upcoming restoration. This one turns smooth and nothing loose internally.
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Thank you!
F-2723 Equalizer CB
More progress. Components swapped, modded and deleted. Cleaned CB(mostly). This CB had a real heavy coating of factory flux or some kid of sealant. Cleaned switch electrical contacts with F5. Greased switch mechanical contacts with L260D. Everything moving and looking nice.
Parked it outside on the hood of the F-250 overnight to air out. The old flux and flux remover is potent!
Work time music provided by the elegant AU-X701. An opening in the GX-5 rack patiently waiting for this leestereo AU-517. Can't wait to hear it
.
More progress. Components swapped, modded and deleted. Cleaned CB(mostly). This CB had a real heavy coating of factory flux or some kid of sealant. Cleaned switch electrical contacts with F5. Greased switch mechanical contacts with L260D. Everything moving and looking nice.
Parked it outside on the hood of the F-250 overnight to air out. The old flux and flux remover is potent!
Work time music provided by the elegant AU-X701. An opening in the GX-5 rack patiently waiting for this leestereo AU-517. Can't wait to hear it
.
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F-2675 Power Supply & Protector CB
This evening's homework. And finally - Sui Glue. First pics evidence fully de-glued and cleaned CB. Used acetone rag pre-soak then easy scraping with a chopstick. There was some glue spill over on adjacent components, spent some time with a dental tool and cleaned up like new. Now that I am describing this, I think I will pull the contaminated components to improve access for cleaning, next time. Can also test them. Repopulated as per leestereo spec. Pulled fuses cleaned and treated holders with D5. Still really appreciating having the CB's out and accessible. Way more fun. And significantly faster and tidyer work.
This evening's homework. And finally - Sui Glue. First pics evidence fully de-glued and cleaned CB. Used acetone rag pre-soak then easy scraping with a chopstick. There was some glue spill over on adjacent components, spent some time with a dental tool and cleaned up like new. Now that I am describing this, I think I will pull the contaminated components to improve access for cleaning, next time. Can also test them. Repopulated as per leestereo spec. Pulled fuses cleaned and treated holders with D5. Still really appreciating having the CB's out and accessible. Way more fun. And significantly faster and tidyer work.
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Thanks Jeff. Good “lead” on the desoldering one end only. I’ll follow that prescription.
Do you or anyone else have any comments on why some of the transistor legs have a black corrosion and some do not? Is this a concern?
Sui-Yogi
Super Member
Hi Jim ,
Nice work with the glue and perfect pictures !!!
About the black tarnish on the leads on the transistors , I haven’t seen one with out it .
Maybe the one you are pointing in the picture with the clean leads , you “accidentally” wipe the tarnish off when you were removing the glue ?
In all of the units that I have replace the transistors the part that is exposed to the atmosphere is always black
There are some restorers that claim that this tarnish can creep in the TO-92 plastic package and that’s not good , others say that this is not the case …..
Nice work with the glue and perfect pictures !!!
About the black tarnish on the leads on the transistors , I haven’t seen one with out it .
Maybe the one you are pointing in the picture with the clean leads , you “accidentally” wipe the tarnish off when you were removing the glue ?
In all of the units that I have replace the transistors the part that is exposed to the atmosphere is always black
There are some restorers that claim that this tarnish can creep in the TO-92 plastic package and that’s not good , others say that this is not the case …..