Old amplifier smell

[jmmartins]

Sometime ago I bought an old Sansui Au-D5, very cheap. First thing I noticed was the smell coming from the amp. It was so bad that I had to put it outdoors because it was impossible to live with that.
I thought … maybe, if I let it turned on outdoors for a week the smell goes out …
Wrong thought … the smell went on, but not so strong.
Maybe some days in the sun could help … wrong idea, after a week, all open … the smell is still present.
What about give it a month of air exposure (open) and then connect it … no results!
With a brush and 2 liters of alcohol I washed every pcb and left it "on" for 4 days now.
Well, the smell is still present. And I cannot identify the origin of it. Is it a part? A capacitor? The protective lacquer of the pcb?
Problem is … the sound is good. It’s a good amplifier, so, anybody has a hint on how to deal with this. I would like to keep it…
Thanks

[Rodeodave]

Can you describe the smell? Cat ****? Solvents?


Edit: What, the word **** gets censored? That ****es me off!
Well, I guess the worst part of censorship is ****

[event horizon]

I very much doubt that it's any PCB laquer. It could be the smell of hot leaking electrolyte from an electrolytic capacitor, though i'd have thought you'd notice the leaking on the PCB.

Here's a suggestion (might appear mad but you might narrow it down), take the amp outside with the lid off & power it up. Block one nostril & with a plastic straw to your other nostril take an olfactory trip around the amp until it smells at it's worst. You should be able to get pretty close to finding the trouble before wretching

[sangram]

I would use a vac set on high exhaust blowing air through the unit. It's probably animal excreta of some kind - we get mostly roaches in our part of the world, and that stuff stinks to high heaven.

Other possibilities are lizard eggs, cat urine, spider intestines (or their victims'), and solid waste from rats or other rodents.

It is usually lodged in the space between capacitors and the PCB, or in the tiny holes left by component legs not fitting completely into the PCB mounting holes. Terribly messy and practically impossible to clean, though a mixture of high pressure air, alcohol and a hot air gun should be able to remove the most offensive odours.

Good Luck!

[wahab]

It could be the phenolic Pcb wich were used extensively
in these amps and were sometime built using inadequate
chemical processes..
I had an amp using such a Pcb, and it s true it smell horrible.
There s nothing to do about it, it will last until the Pcb has
completely evaporated !!

[Andrew Eckhardt]

You could also look for the hot thing. Something might be burning up. If it keeps stinking for that long there must be a Lot of stink left to go. Anyone with some experience might be able to tell exactly what it is by the smell, so if you know a tech, give them a call. If it takes a long time for the stink to get going maybe it's coming from a component with a large thermal mass, like the power transformer. You could have a shorted turn, or an oscillating amplifier. The possibilities are almost limitless. It could be as simple as a bad connection. Visual and temperature inspection could probably nail it.

[poynton]

Hi.

I've had this problem too.....

HELP ! Smelly Circuit Board !

I sold the amp at an open air sale !!!!!



Andy


.

[jmmartins]

Thanks guys

Believe me, it smell,s bad. Hard to describe but is a mixture of electronic smell with some organic thing decomposing. It’s not a faint smell! If I cover the amplifier for a week (not letting the air flow at all) and then uncover … man, my wife almost throw me out with the amplifier…
In fact, i can’t find the origin of the smell because it seems to be everywhere.
My first thought was maybe an electrolytic capacitor but I can’t find any leak.
I tend to believe that Wahab can be right although, it’s hard to believe that a factory could use a pcb that later will evaporate intoxicating everyone around.

[Andrew Eckhardt]

check the main filter caps for heat too.

[40 watt]

Old leaky[ed] electrolytic capacitors. Change them all...final clean the circuit board, smell goes away and for the $50 to $75 you spend on that the amp will run cooler and be back in spec, thus sound LOVELY AGAIN.

Oooh,oooh that smell...will be gone!