AU-717 Deadly Glue

After reading this thread I have alarm bells ringing. I don't have much electronics knowledge where exactly on the au 717 will this glue be when you open the cover. How do you remove the caps. Sometime ago I had some leakage under my au 717 amp, opened the amp up and turned it up side down, there was some corrossive fluid under a brown diode
225k 100v H. Can anyone tell me is this the same symptom. I have also 2 AU-919.s do they have this glue also.

thanks
 
starheaven...
You are describing the 2.2µf film bypass caps which are soldered to the large power supply electrolytics. They do not leak (there's nothing in them that can leak). It's the big suckers that they are soldered to that are the problem.

The board is the regulator board. Sits next to the transformers. Not a novice thing to fool with.

Never woked on a 919, but I have no reason to believe Sansui didn't use the glue on them also.
 
acetone

if ya ever run out and the hardware store is closed, nail polish remover is guess what...mostly acetone....go to the local drug store
decent solvent, evaporates way fast...
a bit pricey but the very best solvent I use is methyl ethyl ketone...it will dissolve stuff that nothing else will touch, test it on a part of the assy you dont care about, powerful stuff...dont smoke no power on yadayada
Casey
 
The glue is on caps otherwise the vibration would overtime make them separate from the board aka no sound :tears:


starheaven said:
After reading this thread I have alarm bells ringing. I don't have much electronics knowledge where exactly on the au 717 will this glue be when you open the cover. How do you remove the caps. Sometime ago I had some leakage under my au 717 amp, opened the amp up and turned it up side down, there was some corrossive fluid under a brown diode
225k 100v H. Can anyone tell me is this the same symptom. I have also 2 AU-919.s do they have this glue also.

thanks
 
scottrt said:
I Live in CA and just looked at a can of acetone I bought at Ace Hardware. Indeed, it has NO health warnings o the label of any kind, except for the usual dont breathe the fumes...
No Prop 65 warnings, which, by the way, adorn every gasoline pump in the state.

Just thought I'd share....
Scott T.

I did a Google search on acetone carcinogen and there's a lot of stuff out there. The jury seems to still be out on whether it causes cancer. I wouldn't drink it, I don't think. And it is highly flammable. So, use good ventilation and no heat around it. The polish remover is a good bet, and anyway you won't need that much of it. By the way, it's in cigarette smoke, too.
 
That Sansui glue…& AU-717 strip down

All sorts of solvent type products have been suggested to help remove the glue that was put on/around the larger electrolytic capacitors to stop them being shaken out of the PCB’s in transit.

I have only just begun restoring my AU-717 so had not closely examined the “goop” on my PCB’s. I was surprised to find that although some of it was hard like dried varnish the rest was rubbery or toffee-like in consistency. To remove the electrolytic capacitors from the driver boards, after de-soldering, I had to cut through a membrane of stretched rubbery goop between the PCB and the cap with a penknife.

For the cleaning …
Small penknife (blunt). The solvent I used is “Hammerite” Thinners and Brush cleaner. This proved to be very effective in softening the glue – The rest was just patience (lots of it) and careful scraping with that blunt penknife. I am not sure if “Hammerite” (metal paint) is sold in the US (or other than UK) – any alternative should be carefully tested first.

The solvent in question has the following characteristics
· Evaporates cleanly from the PCB.
· Does not smell much, and disperses rapidly.
· Does not remove the silk screening (paint) from the PCB.
· Will also clean flux from the other side of the board after soldering.

Here is a link that I found to another detailed and thorough AU-717 strip down with more on glue cleaning.

http://www.geocities.com/cdkands/AU717-1

I am so glad to have lost that incense // confectionery // cats pee smell from my AU-717.
 
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All sorts of solvent type products have been suggested to help remove the glue that was put on/around the larger electrolytic capacitors to stop them being shaken out of the PCB’s in transit.

I have only just begun restoring my AU-717 so had not closely examined the “goop” on my PCB’s. I was surprised to find that although some of it was hard like dried varnish the rest was rubbery or toffee-like in consistency. To remove the electrolytic capacitors from the driver boards, after de-soldering, I had to cut through a membrane of stretched rubbery goop between the PCB and the cap with a penknife.

For the cleaning …
Small penknife (blunt). The solvent I used is “Hammerite” Thinners and Brush cleaner. This proved to be very effective in softening the glue – The rest was just patience (lots of it) and careful scraping with that blunt penknife. I am not sure if “Hammerite” (metal paint) is sold in the US (or other than UK) – any alternative should be carefully tested first.

The solvent in question has the following characteristics
· Evaporates cleanly from the PCB.
· Does not smell much, and disperses rapidly.
· Does not remove the silk screening (paint) from the PCB.
· Will also clean flux from the other side of the board after soldering.

Here is a link to a detailed and thorough AU-717 strip down with more on glue cleaning.

http://www.geocities.com/cdkands/AU717-1

I am so glad to have lost that incence // confectionary // cats pee smell from my AU-717.

Is that what that smell is. I kept blaming it on my cats. The don't usually get to go in the listening area. I must apologize to them tonight.

Rick
 
Your poor cats !... reckon they deserve a catnip mouse each as a consolation.:yes:

I kind of knew it wasn't cats, cos we dont have one :scratch2: no offence to cats by the way regarding the description of the smell, but their pee can sometimes have a similar smell.

PS I am a cat lover :yes: Wife allows me this hobby :thmbsp: but no cat :pity: she hates them.
 
Hyperion - excellent restoration the the Sansui! Excellent work! :yes: :thmbsp:

I like the idea of drilling small holes in the sealed volume control.

I have a Kenwood Model 500 amp that I'm going to restore and have been told
that it has a sealed volume control as well.

Have you ever worked on one to where you might know which layers the holes
need to be drilled into?

Also, what's the name of the water based polish you used on the output transistors
and how did you apply it? Soft cloth? Fine brush?

Thanks!
Scott
 
SPL db
Whoah there... that is not my link or my AU717 - I included the link for interests sake and because it had more about Glue removal - (I copied the technique used there). Only the text in the reply is from me.

I already edited the post once to clarify it because I got the impression EchoWars (bless him) might have thought the link was mine.

Regarding the volume control and drilling holes - be very very sure you are clear about what you are doing when drilling... as one slip, and you'll be looking for a replacement volume control on eBay faster than you can say "knife"!

I did buff my outputs though - just used a soft cloth - (a yellow duster) - which had just a suggestion of some old shoe polish (black) on it - worked a treat.

Good luck with your Kenwood Model 500
 
Au-717 site

ya... http://www.geocities.com/cdkands would be my site. Glad you have found it useful.

Yes... be careful when drilling the holes in volume controls. You don’t want to overshoot too much . I find most alps type of controls can be drilled. however, I have see some older style can type pots that have the resistive surface around the outside wall of the can (not on the front/back faces of the pot). So make sure you know what you are drilling into.

I have added a section on the home page about the sansui glue problem (in the left nav bar). I offer my theories on what is happening. Hope all this helps you folks bring back some of those ageing works of audio art.
 
Hi there megawatt!

You have a great website! - the new "glue" pictures are very revealing! - I have already decided to replace all the 10K resistors, 8 of them, (which on my board are all glue damaged) as well as the caps.

I am not nearly as brave/thorough as you, with my AU-717 strip down, but I have to say that link on your website was what convinced me to do mine.

Thank you so much for publishing all your hard work and in such detail. :thmbsp:
 
With all this talk about drilling holes in volume controls, I thought I'd mention that the dual-pot on my AU-717 needed a good spritz as well to clear up some scratchiness.
But all I did was to remove the four screws that hold the sections together.

You don't need to go any further than that, because you can separate the sections just barely enough to manage a shot of de-oxit and then screw it back together.
Just be careful not to twist anything around while you're handling it.

Drilling works, but screwing is always more fun. Er, you know what I mean.
 
Ya... the screw thing works too (sometimes). I find on some alps type pots it does not work. So I use the drill technique. I find the access hole in the side gives great control over where solutions is applied (I use the 100% deoxit solution with the needle applicator). Be careful when pulling and twisting the pots with the screws out... damage can ensue.
 
All sorts of solvent type products have been suggested to help remove the glue that was put on/around the larger electrolytic capacitors to stop them being shaken out of the PCB’s in transit.

For the cleaning …
Small penknife (blunt). The solvent I used is “Hammerite” Thinners and Brush cleaner. This proved to be very effective in softening the glue – The rest was just patience (lots of it) and careful scraping with that blunt penknife. I am not sure if “Hammerite” (metal paint) is sold in the US (or other than UK) – any alternative should be carefully tested first.

The solvent in question has the following characteristics
· Evaporates cleanly from the PCB.
· Does not smell much, and disperses rapidly.
· Does not remove the silk screening (paint) from the PCB.
· Will also clean flux from the other side of the board after soldering.

In my earlier life, I spent over 25 years in the paint and body business (owner/operator) so I got used to looking at the "P Sheets" (product sheets) that got to the nitty-gritty of what a product consisted of and the how and why it was supposed to work.

I did a little digging and found the P Sheet for the "Hammerite Brush Cleaner and Thinner" because I wanted to see EXACTLY what the ingredient was it contained that gave you the results you state.

So for reference, it's almost totally acetone (with a dash of ketone added for flavor :D ) . Most people know that acetone is a very common thinner available in most places.
Note that the significant difference between acetone and lacquer thinner (which contains acetone) is that lacquer thinner is designed to evaporate slower in order to promote the "flow" of paints it's used in while acetone evaporates much quicker.
I think the advantage of using fast evaporating acetone might be that it evaporates so fast that while it will soften the glue, it doesn't hang around long enough to hurt the board itself.

http://www.icipaints.co.uk/products/info/hammerite_brush_cleaner_and_thinners.jsp
On that page, click on the "PDF Product Data Sheet".

I find that I can do pretty much anything I need to do as far as cleaning any part of the insides of an amp/tuner with either pure alchohol or high grade acetone.
 
drill and pots

oh... yes, one last thing on drilling holes in pots. some pots you just dont have access in to. The kenwood ka-8100 contains some of these. I run accross this often so I picked up the habit of drilling holes for access whenever other options did not present it self. The Sansui alps can be un-screwd & cleaner can be applied. I was never comfortable with this, and I use the drill technique on so many others pots with success I just kind of stick with what works. But hay!!! whatever works... right? :thmbsp:
 
This is a great thread! Thanks to EW for starting it (back in March). And also kudos and super-thanks to Megawatt. The minute I won the ebay auction (AU-717), I was up all night scouring the net for any and all related information -- and the most impressive thing out there was your excellent piece of geocities webcraft (not to mention the super-dooper technical craftsmanship). I printed it all in color and put it in my "audio file" (ha!). I am tuly inspired. I love to work with my hands, learn new things, and feel the sense of accomplishment that comes with this type of undertaking. Now... if all my customers/clients would go away for a week and the kids ballgames, band concertes and homework could be put on hold, plus tell the realtives to go fish and... hope my wife won't care if I disappear for an extended period -- THEN -- I might be able to start a 717 mini-restoration (but not anywhere near what you dudes are doing). My cosmetics are good, but the inside needs a simple once-over. Just a day or two with no interruptions or other demands -- that's all I need!
 
Sansui Glue

I had some issues with a G-9700 where I could not adjust the off set voltage, or when I could it would not stay adjusted. After carefully cleaning all the glue off that had been covering several components on the driver boards, the problems have gone away. Who would have thought?
 
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