Which Sansui gear has the "glue problem"

[Hyperion]

Can you please describe this smell? My G-8700DB often has a freon-like smell after it's on for 10 minutes or so. I keep a small fan on the vents to help dissipate heat, but the smell persists. Is this a glue issue? Is any action warranted? (I have cleaned it thoroughly inside and out; deodorizers such as OdoBan have no effect.)

Well, it's far from clear that the smell is actually from the glue, and could be from the PCB's themselves, or something else. The smell is variously described as a 'confectionery', 'citrus fruit', 'cats pee' kind of smell. The smell is dramatically reduced after a reconditioning which includes glue removal, and a change of all electrolytic capacitors, and washing the boards with flux remover (when I do a recondition).

 

[pete_mac]

Sansui AU-419

No glue in this model ... as it doesn't exist!

 

[Daunia 70]

No glue in this model ... as it doesn't exist!

Cheers,that should've been AU-417 :thmbsp:

 

[Hyperion]

AU-7900 - confirmed, it's neatly applied so you might not think it's there but it is

 

[Cafad]

Did the glue get used all the way through to the Alpha series or did its use stop some time in the mid 80's?

 

[pete_mac]

Did the glue get used all the way through to the Alpha series or did its use stop some time in the mid 80's?

I’ve seen a number of Alphas with glue, including the 907 Limited.

 

[Bumpalump]

Almost all of the vintage gear has the problem, there is no surprise that over 20 or more years ago gear need a professional service

 

[tsd71]

I know its off manufacturers topic but watch out for Realistic STA-2000, 2100, 2100D, 2300, they all use excessive glue. I had a 2100 that ate resistors and diodes on the power supply and amp boards.

 

[savatage1973]

At least the Sansui glue only gets corrosive (and not all of it does), but there is a glue used by a couple manufacturers (and which ones escape me at the moment) that can turn conductive, resulting in shorts and catastrophic failures.

 

[kevzep]

At least the Sansui glue only gets corrosive (and not all of it does), but there is a glue used by a couple manufacturers (and which ones escape me at the moment) that can turn conductive, resulting in shorts and catastrophic failures.

Yep Sansui has that too......

 

[Skywatcher]

At least the Sansui glue only gets corrosive (and not all of it does), but there is a glue used by a couple manufacturers (and which ones escape me at the moment) that can turn conductive, resulting in shorts and catastrophic failures.

Sonybond is/was the most widely used by almost every "brand" back in the day and I don't think they knew what would happen after it ages. Some of the assembly workers got carried away and blobbed on too much, and/or where it wasn't really needed.. However, even some of the newer "brands" use a glue that does the same thing, but dries, turns dark with heat and becomes brittle. It's harder to get off than the Sonybond, which was a solvent based adhesive. "They" (some companies) know it's effects and still use it... It's built-in "self destruct". Some have gone to using hot glue which is OK if it comes loose a year or so later. It's only needed for the trip across the pond and being trucked to it's destination. Except for on speaker crossovers and subwoofer amps that are subject to high vibes. I do use a high-temp solvent based adhesive on larger capacitors when I know the unit will be getting shipped, or travel around. But I only put a small dab or two where it is needed, never on or near any leads of components. Smaller caps don't need any.

 

[Skywatcher]

Can you please describe this smell? My G-8700DB often has a freon-like smell after it's on for 10 minutes or so. I keep a small fan on the vents to help dissipate heat, but the smell persists. Is this a glue issue? Is any action warranted? (I have cleaned it thoroughly inside and out; deodorizers such as OdoBan have no effect.)

Freon doesn't really have much of an odor though the refrigerant compressor oil does (I am an old refrigerant tech), but I know what you mean. As old as your system is, the glue would have off-gassed years ago and have no remaining odor. If anyone has serviced it within the past few years, there may have been some "cleaner" of some sort used and it was absorbed into something. It is possible the air passing through it is being ionized by the heatsink. Some "air fresheners" create a weird "chemical" odor when the air is "charged" somehow. Sort of like the "smell in the air" after a lightning strike, or having a toaster that is always plugged in (the element is still "hot" on one side and attracts particles) and as soon as you energize it, that "ionized" smell fills the air for a few moments until whatever gathered on the element is burned off. Of course your heatsink isn't hot enough to "burn off" anything (better not be! lol!), but is still warm enough to spread the odor from convection. OdoBan and other deodorizers (especially ones that you "plug-in) may be actually exacerbating the odor.

 

[smurfer77]

Hyperion has already mentioned the AU-9900. Both of mine have the problem.

There was a thread on AK about the AU-X901 with the glue problem and sadly I can confirm that the AU-Alpha707 which is the japanese domestic version of the AU-X901 has the same issue. In fact the photos on that thread might as well be pics of mine before I cleaned up the glue. Had to replace several resistors, jumpers, 4 transistors and two caps.

 

[Bugetnirvana]

I just removed the glue from my AU 517 power board. I made a couple of scrapers from 1/4" plexiglass, just cut a couple little pieces on my bandsaw and gave them chisel points sanded down sharp. Took about 5 minutes to make them and they worked great. Got the Idea from Skippy_124's scraper here http://www.audiokarma.org/forums/in...store-with-a-little-sting-in-the-tail.478947/

 

[Skywatcher]

I just removed the glue from my AU 517 power board. I made a couple of scrapers from 1/4" plexiglass, just cut a couple little pieces on my bandsaw and gave them chisel points sanded down sharp. Took about 5 minutes to make them and they worked great. Got the Idea from Skippy_124's scraper here http://www.audiokarma.org/forums/in...store-with-a-little-sting-in-the-tail.478947/

Great idea! I usually put a few drops of toluene on the glue, let is sit for a few minutes, drop some more on (if needed as it dries relatively quick, but not "instantly") and the glue wrinkles up and lifts off nicely with minimal scraping needed. Though at times you do have those "stubborn" blobs. Toluene won't hurt plastic *except* styrene caps, though it really doesn't hurt them, just makes 'em ugly, and dries without leaving any residue. The less scraping, the better.