Re: Burned ferrite bead RTX 2080 LB617
They are ferrite beads. They are labeled LB617 and LB618.
Hard to say if they are the cause of the artifcating. Remove them, clean up the boards, check if traces are damaged. You can start by just replacing them with 0-ohm jumpers and see if that fixes it. I can't tell what package size those are, maybe 0603?
If the ferrite beads are in fact needed for proper function (and not just as EMI mitigation) you can start with a chip bead with Z = 10 - 50 ohms @ 100MHz, and go up from there, swapping out beads until it works...
TheLaw
Badcaps Veteran
Last Activity: 08-21-2023, 05:48 PM
Joined: 01-03-2011
Location: New Jersey
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Re: Is there a manufacturers tolerance for ripple?
No. A capacitor's ability to smooth out voltage ripple is related to its capacitance and ESR. Whether a given capacitor can "smooth out voltage ripple" is totally dependent on the requirements of the application. I've designed power supplies running polymer caps at 1.5-1.8x the rated ripple current rating (with forced air cooling) and the voltage ripple is plenty acceptable.
The ripple current rating is derived from the temperature rise of the capacitor core, that is the self-heating due to I(ripple-rms)^2...Leave a comment:
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Re: Is there a manufacturers tolerance for ripple?
The ripple current rating is generally used as a point of guidance in selecting a capacitor. It's not a hard limit, unlike the voltage rating, for instance.
Each switch-mode topology has a set of equations which govern the (theoretical) RMS ripple current in the input or output capacitors. It is generally good practice to select a capacitor with ripple current rating higher than the actual RMS ripple current. But, it is not strictly necessary.
You can run a capacitor at 2x its ripple current rating (for...Leave a comment:
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Re: Replacing low value electrolytics with ceramic?
If you want to visualize how capacitance drops with applied DC bias voltage, you can check out Kemet's KSIM web app:
[url]https://ksim3.kemet.com/capacitor-simulation[/url]
The limitation is fundamentally package size, and more directly, the physical amount of dielectric material contained. Since Class II ceramics are ferroelectric, they "saturate" similar to how an inductor's core might. More material means it saturates less under the same DC bias conditions.
Beware of "too...Leave a comment:
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Re: Modern Samxon and Teapo caps much better these days?
I don't know for sure. I think Chinese companies have gotten a big enough credibility boost over the last decade that they [I]do[/I] have some reputation to protect and uphold.
Samxon has reported to our company that they have widespread material shortage issues (just like everyone else) and they too can't meet delivery dates. I don't know if that's evidence that they're not substituting inferior material, but maybe it's worth something.Re: Modern Samxon and Teapo caps much better these days?...Leave a comment:
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Re: Oscilliscopes
[url]https://www.tequipment.net/Instek/GDS-1054B/Digital-Oscilloscopes/[/url]
The 50MHz 4-channel verison is selling for <$350USD. I'm aware of how cheap the Rigol is, and while it was absolutely amazing 5-6 years ago when they got popular (and no one else could touch the price), these days, I think Siglent, GWInstek, and others give you a much more enjoyable, much less frustrating experience for comparable price.
I've used the low-cost models from Tek, GWInstek, Rigol, and Siglent in a professional setting, for many hours...Last edited by TheLaw; 02-17-2021, 02:18 PM.Leave a comment:
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Re: Oscilliscopes
I like GWInstek GDS-1054B. I find the user interface waaaay better than Rigol, and on-par with Siglent. We have a GDS-1054B at work. It's pleasant to use.
At home I have a GDS-2104E, which I really like. Zippy UI, no frills. Good value.
The budget Rigol scopes are just so dang sluggish. I know everyone seems to love them, but if you've used a scope with a good UI, you will find the Rigol frustrating.Leave a comment:
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Re: Modern Samxon and Teapo caps much better these days?
Good point. I'm pretty confident I've seen bags from Mouser from Nichicon with Malaysia country of origin. Same for Nippon Chemi-con. I haven't seen a made in Japan Panasonic in about 10 years.
Confirmed below:
[url]https://www.nichicon.co.jp/english/company/com_isots01.html[/url]
[url]https://www.chemi-con.co.jp/e/company/bases.html[/url]
The enthusiast PC market is still beating the "WE ONLY USE JAPANESE CAPS" drum, somewhat ironically,...Leave a comment:
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Re: Modern Samxon and Teapo caps much better these days?
I haven't been on this forum in years, but, now that I work in power adapter design, with a factory (wholly owned by the company) in China, here's my input:
Samxon, Aishi, Teapo, and Jianghai are quite solid, particularly if you use their higher end caps.
For Samxon: SK and SH. For Aishi: RJ and RZ, and so on...
We've done some accelerated life testing with these caps and have seen no issues. Most important part is to use adequately rated parts in the first place, of course.
...Last edited by TheLaw; 12-16-2020, 11:02 AM.Leave a comment:
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Re: Oscilloscope
I just snagged a 100Mhz Tek 465M for $70 shipped off eBay.
It's sweet.Leave a comment:
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Re: What an analog ESR meter will and won't do
I got interested in making one again. Can you explain what you mean by transformers and lowering their series resistance etc?
Thanks....Leave a comment:
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Re: These are Sacon FZs right? *sigh*
Yes very well....Leave a comment:
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Re: Did i buy a bad capacitor (TAICON) ?
If the capacitor has exploded, yes that is almost 100% the problem. Taicon isn't the worst, but there are much better replacements. A low ESR cap from Nichicon, Nippon-chemicon, Panasonic, Rubycon, Samxon, or even Teapo would probably be a better bet. I don't know where you can get your parts from but...those would probably work fine.Leave a comment:
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Re: These are Sacon FZs right? *sigh*
Finally did the recap.
Went with 6x 1000uF 6.3v Nichicon/FPCAP, 1x Chemicon 100uf 10V PS.Leave a comment:
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Re: The most stressed capacitor in PSU
Typically the caps that do the filtering after the switchers because those have quite a bit of ripple and noise due to the nature of switchers. The high voltage caps don't usually see too much abuse. The small coupling caps are typically fine too or those associated with a controller of some sort.Leave a comment:
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Re: I need a new multimeter but don't want to spend a fortune.
I dunno. They look pretty high quality to me...I don't know about those surface mount pots...but otherwise looks good.
Regardless, it's your choice. An Amprobe or Extech are pretty good values for the money as well....Leave a comment:
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Re: I need a new multimeter but don't want to spend a fortune.
Not a bad choice for $35. Something happened to your pictures...Maybe you can reupload them?...Leave a comment:
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Re: I need a new multimeter but don't want to spend a fortune.
Fluke 17B- $80
It's a "China-only" genuine Fluke. Honestly, after looking at many reviews, there is really nothing but good things about this meter. Excellent quality construction. Just as good as USA Made fluke meters, in my opinion.
High precision components, SMD metal films, SMD tantalums, like 3-4 MOVs, PTC, nice big resistor, high rupture fuses (HRC), really high quality input jacks, and an excellent quality PCB, similar (maybe the same) as the ones Fluke USA uses. It uses two...Last edited by TheLaw; 09-15-2011, 07:12 PM.Leave a comment:
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Re: What an analog ESR meter will and won't do
Ahh. Is it possible you make a small write-up? Maybe some pics? I'm not sure if anyone else is following this thread, but this would be one of the only analog ESR meters that might be capable of detecting failure of lower-ESR caps, which is helpful.
If you're not feeling up to it, don't, but it might be a good resource....Leave a comment:
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Re: What an analog ESR meter will and won't do
Eventually I may want to try to make one of these cheap analog ESR meters...What modifications did you make (exactly) to achieve the range you got on yours?
Thanks....Leave a comment:
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