The two Lelon brand filter caps in the power supply section of my stereo amplifier have very slightly (and unevenly) - but definitely - rounded tops. I see on this site that Lelon is a known bad brand. This amp is only like 10 years old, and is a typical solid state class B design; for this type of circuit, from what I've read online, this shouldn't typically be expected, so I just wanted to throw this ultra noob question to the experts and see whether I should recap, or if I'm just making up problems. Thanks.
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Re: Just a little bulge = bad caps?
"but definitely - rounded tops. I see on this site that Lelon is a known bad brand. This amp is only like 10 years old, and is a typical solid state class B design;" Yes, recap, its 10 years old, by the way its Class A/B, Class B will sound real bad.Never stop learning
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Re: Just a little bulge = bad caps?
rounded PLASTIC tops or metal ones?Comment
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Re: Just a little bulge = bad caps?
Pictures would help.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: Just a little bulge = bad caps?
Thanks for your replies. The tops are thin black plastic, so I don't know exactly what is going on underneath the plastic. I'll get some photos this evening to show what they look like.Comment
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Re: Just a little bulge = bad caps?
Normally the plastic cap on th top of the capacitor tends to bow and dome over time due to heat ect. Best bet is to see if you can push down on them, If you can push them down most likely the cap is good if you cant and there is obvious pressure under the plastic cap remove but cutting it off it and see if the capacitor can is actually bulged. Most likely the cap is fine.Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !
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Re: Just a little bulge = bad caps?
Pull them out and test them.Comment
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Re: Just a little bulge = bad caps?
I pressed on the plastic tops and they didn't give, so I removed them to see what's underneath. As you can (hopefully) see, the metal tops are slightly bulged. I think the schmutz is maybe adhesive to adhere the plastic tops to the metal, but I can't tell...I couldn't see any actual break inthe metal.
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Re: Just a little bulge = bad caps?
those are shot.the schmutz is leaked electrolyteComment
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Re: Just a little bulge = bad caps?
yea, those are done.
the electrolyte leak is in the center of the longest pressure release-section - dead givaway.Comment
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Re: Just a little bulge = bad caps?
Well, OK, then! Thanks, fellows. It's nice when the answer is so straightforward!Comment
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Re: Just a little bulge = bad caps?
They are failed alright :LPlease Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !
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Re: Just a little bulge = bad caps?
yup, goners.<--- Badcaps.net Founder
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Re: Just a little bulge = bad caps?
The curiosity is: what made you look into this problem?
Usually amplifiers, to get rid of any noise, do not use switching PSUs and use heavy linear filtering supplies. That's why those caps are huge 0.01F units, but at least they usually are under lower stress.
Not to say they can't fail or are unaffected by the electrolyte problems, but are you getting 60/120 cycle hum in your speakers or something? Or does it sound OK, but you just look at them and appear odd?Comment
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Re: Just a little bulge = bad caps?
thanks for picturesComment
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Re: Just a little bulge = bad caps?
eccerr0r:
I started noticing that I was getting light buzzing out of the speakers when the input attenuation pot was turned to about 6 or 7. I searched high and low for the cause, but couldn't find anything in terms of grounding or anything. I'm new to a lot of this, so it wasn't until reading about bad power supply caps that I realized they could even be a source of excessive hum (not to say that's necessarily the cause of my issue).
So long story short I was just kind of digging around and noticed they looked suspect.Comment
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Re: Just a little bulge = bad caps?
Well, the other thing is that most audio/linear amplifiers have a specification to reject power supply noise too, so hum can be attenuated through this as well.
I still kind of find it weird that if the caps really did rupture, why didn't at least one rupture at the vent lines' weakest point - where the two lines meet...Comment
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Re: Just a little bulge = bad caps?
the weakest point is the point that the cut is deepest., not at the junction.Comment
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Re: Just a little bulge = bad caps?
What's the voltage?Less jewellery, more gold into electrotech industry!
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Re: Just a little bulge = bad caps?
There was and is about +/-53v across the capacitors under power. The old Lelon caps I asked about originally were 50v, 85C devices. I replaced them with Vishay/BC Components 63v, 105C units, so I guess even if the old ones were still "OK" by some measure, it's better to have 10-year-newer ones from a better brand with higher ratings.
(I assume it's a better brand; I see Lelon on the bad caps thread but don't see anything about BC in the good or bad brand threads, but the ones I got were the only ones I could find with those specs that would fit in the case).Comment
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Hi guys, this is general query really
So I have a Hill DX3000 3KW audio amplifier here.
It has a topology/design like a class A/B but all the banks of output transistors (10 transistors in each 'side' of the channel) are NPN.
I was wondering what class this is. It doesn't fit the description of class A.
It also doesn't match class A/B or B amplifiers as all the examples I see have a complimentary output stage desigs (NPN/PNP) and clearly is not G, H or D
I looked for 'class A push pull' but that didn't tell me anything either
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Since changing the cable to a thicker Class 2 unit, this problem has not occured again - do you know of other marginal "Class 2" HDMI cables supplied with displays?09-06-2023, 08:50 PM -
Hi all!
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I'm aggregating information as to how I should remedy this. It hasn't exploded yet, but that's what I'm trying to avoid.
I've never seen a RIFA class Y safety cap self destruct (or at least it hasn't been documented in the past). However, it's not worth the risk to leave it in there.... -
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Micron MTFC2GMDEA-0MWT, MTFC4GLDEA-0MWT, MTFC4GMDEA-1MWT, MTFC8GLDEA-1MWT, MTFC16GJDEC-2MWT, MTFC32GJDED-3MWT, MTFC64GJDDN-3MWT are a communication and mass data storage device that includes a Multi Media Card (MMC) interface, a NAND Flash component, and a controller on an advanced 11-signal bus, which is compliant with the MMC system specification. Its low cost, small size, Flash technology independence, and high data throughput make eMMC ideal for embedded applications like set-top boxes, digital cameras/camcorders, digital TVs, and a variety other consumer products.
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