Hi All. I have an old rotel amplifier at home. I pulled it apart the other day to look inside. When I did I noticed this dark brown, nearly black stuff at the base of some of the capacitors.
What is this?
Is it glue or is it something that has oozed out of the capacitors?
Any advice you can give me will be very much appreciated.
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What is this?
Is it glue or is it something that has oozed out of the capacitors?
Any advice you can give me will be very much appreciated.
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Looks like glue to me.
Those are VERY tall capacitors to withstand banging around with only the two terminals to hold them down.
In my own constructions, I use construction adhesive or weatherstrip adhesive. I've found silicon seal doesn't hold very well.
Those are VERY tall capacitors to withstand banging around with only the two terminals to hold them down.
In my own constructions, I use construction adhesive or weatherstrip adhesive. I've found silicon seal doesn't hold very well.
I think that after soldering, a quick check for rocking components and possible shipping vibration issues, they pour this material to seal loose joints and create a solid foundation .
Eliminates warranty issues that could quickly multiply maybe
It doesnt look like its coming from the solder terminals overall.
Eliminates warranty issues that could quickly multiply maybe
It doesnt look like its coming from the solder terminals overall.
There is some stuff coming from the terminals and the tops do have a bulge in them. They are 8200uF and measure about 7300uF not sure if they are ok.
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Maybe its a combination of both. Maybe there is glue there and maybe the capacitors are shot too.
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1991 is more than 15 years. I'd replace them just based on the date, not to mention the low value. If I go to the trouble of taking something apart, I replace e-caps over 10 years old. Even if they havnn't contaminated everything with chemical slime yet. These aren't either of the two varieties of epoxy sealed cap I know about.
I use the e-caps rated >3000 hours service life from panasonic, nichicon, rubicon, or if I have to Nippon Chemicon, CDE, or multicomp. The first three, I've never had the country of origin be the land of fake baby formula, fake school building concrete, fake chicken, fake branded seasoning.
I've had to replace e-caps 4 times in a 1961 build amp, and that would be stupid now we have the internet and I can buy something better than TV parts store **** stock.
I use the e-caps rated >3000 hours service life from panasonic, nichicon, rubicon, or if I have to Nippon Chemicon, CDE, or multicomp. The first three, I've never had the country of origin be the land of fake baby formula, fake school building concrete, fake chicken, fake branded seasoning.
I've had to replace e-caps 4 times in a 1961 build amp, and that would be stupid now we have the internet and I can buy something better than TV parts store **** stock.
This is from my ART SLA1.
In the close-up, the top of left cap is already splitting open.
Regards
Mike
In the close-up, the top of left cap is already splitting open.
Regards
Mike
I reckon the caps are shot , i don't recall any Rotels i've owned having them glued down ,normally this type of glue is white or clear and the manufacturers who use it tend to use huge dollops of it ,to my eyes it looks like leaky caps unfortunately.
The pins looks corroded that is for sure, but the black gel looks like glue, it won't definitely crept up on the caps body unless the amp is placed upside down...
Those are big caps for the psu I think, so it is glue for sure to hold them tight in place to control vibration.
[refer to stuartmp photos]
Those are big caps for the psu I think, so it is glue for sure to hold them tight in place to control vibration.
[refer to stuartmp photos]
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Thanks guys. So the consensus is that the black stuff is glue and the caps are shot... no big deal... I will just order some from digikey... thanks for everbody's input.
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At that age I would be replacing the electrolytics anyway.
Be sure to clean up the gunk before soldering in the new caps.
Be sure to clean up the gunk before soldering in the new caps.
I own a Rotel RA971-MKII which I seldom use.
The caps (BGs mostly !), seem to be sitting on exactly the same stuff as in the first pic of post#1.
Have not desoldered anything to look what's going on underneath. No bulging or signs of the brown stuff up the sides though
All the hallmarks of bad design on that one, as im sure you know. Cheap crappy caps, and board overheating around high current paths because they used cheap crappy less than 1oz SRBP board
Yeah. Disappointing.
I cannot understand why manufacturers do this. All the trouble to design and manufacture a product and yet can't get some basics right.
I cannot understand why manufacturers do this. All the trouble to design and manufacture a product and yet can't get some basics right.
It all comes down to maximizing profit margins in the end , the Hi-Fi industry like any other is full of potentially great products let down by the need to save on production costs,from low grade caps with short lifespans to unsupervised production at 3 rd rate factories in a far off land.
Long gone are the days that you could buy an amp and expect 20 years trouble free service.
Same with cd players ,glass lenses replaced by plastic that fail rapidly , i could go on 🙂
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