Re: CMR or SMR?
If given a choice, why would anyone prefer SMR?
Unless you mean, taking also capacity into consideration.
goop
Member
Last Activity: 02-06-2021, 07:26 AM
Joined: 05-12-2014
Location: city
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Re: HP bios password unlocking
Why?
Is the chip supposed to be powered even though the laptop's off?...Leave a comment:
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Re: Which Eprom programmer to buy
What's the power/logic voltage of the various EZP20xx?Leave a comment:
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Re: Sceptre32 MegMeet mp116 Solved
I don't have it available. If you find nothing else, maybe worth trying to ask the manufacturer: [url]http://www.megmeet.com/siteen/ywlx/1635.html[/url]Re: Sceptre32 MegMeet mp116 Solved<b...635.html[/url]Leave a comment:
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Re: No power on from standby. Same with two PSUs. (No brand TV)
I see. It's not branded UMC, and actually the two TVs are each branded slightly differently, but if they all use the same Cultraview logic board their faults might be similar.
Is it possible to ascertain somehow that it's the flash?
Should it be possible to read and write the chip in-circuit?
Why would flash get corrupted so easily?Leave a comment:
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Re: No power on from standby. Same with two PSUs. (No brand TV)
What's UMC?Leave a comment:
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Re: No power on from standby. Same with two PSUs. (No brand TV)
Why do you say that?Leave a comment:
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No power on from standby. Same with two PSUs. (No brand TV)
I have two units of the same TV. One does not power up from standby (standby light is on), the other does. I switched the PSUs between them and the problem stayed on the same TV, so the PSU is okay (Megmeet MP116A rev 1.0. Photos on [url=https://www.badcaps.net/forum/showpost.php?p=560135&postcount=20]this thread[/url]).
I guess that means the problem is the logic board, which is a [url=http://www.cultraview.com/en/index.html]Cultraview[/url] CV181H-X-41C (a brief spec for the [url=http://www.datasheetspdf.com/PDF/CV181H-X-40C/729213/1]CV181H-X-40C here[/url], the 41C is similar):...Last edited by goop; 05-19-2015, 07:30 AM. -
Re: Sceptre32 MegMeet mp116 Solved
Here's the Megmeet MP116A, Rev 1.0, 2010/09/28:
[url=http://imgur.com/87mcdb5][/url]
[url=http://imgur.com/rpXtIvJ][/url]
[url=http://imgur.com/hUXZm43][/url] [url=http://imgur.com/dk6w80s][/url] [url=http://imgur.com/Wushxj1][/url]
(I don't know why the forum ruins the links to the large images, so here they are plainly: [url=http://imgur.com/87mcdb5]top[/url], [url=http://imgur.com/rpXtIvJ]bottom[/url], [url=http://imgur.com/hUXZm43]left[/url], [url=http://imgur.com/dk6w80s]middle[/url], [url=http://imgur.com/Wushxj1]right[/url].)...Last edited by goop; 05-16-2015, 07:50 AM.Leave a comment:
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Re: How to identify capacitor function?
I suppose when you have enough experience, you can infer or guess the function without tracing connections and reading datasheets.Leave a comment:
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Re: How to identify capacitor function?
stj: Just a better understanding of the above PSU, and similar ones.
budm: For a useful experiment I'd first need more knowledge.
I didn't mean the general function of an optocoupler, but its role in the specific circuit.
Anyway, all right. I'll proceed to unguided reading.
Thanks for the PDFs.
Last edited by goop; 05-07-2015, 11:53 AM.Leave a comment:
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Re: How to identify capacitor function?
If it can work well, sure. But I guess some circuits may rely on having a certain ESR range.
budm: Thanks.
Can't check the IC model directly anymore.
Regarding adding external resistance, won't it require a more extensive analysis to tell for sure how a higher resistance affects the circuit? For example, it might seem functional superficially, but will have latent side effects. More noise, components that are driven harder, etc.
What's the function of the optocoupler?...Leave a comment:
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Re: How to identify capacitor function?
So that IC runs on 12V? What's the 1.6V for? If low ESR isn't required, did they use it just because of stock or price concerns?Leave a comment:
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Re: How to identify capacitor function?
I thought since you had a guess for the function of the capacitor in that quoted post, a few more details and you would be able to tell with certainty what it is for.
The PSU works now. I was just curious about what you said.
Someone uploaded shots of this specific PCB before. It's C103, the bottom one:
[url]https://www.badcaps.net/forum/attachment.php?attachmentid=31315&d=1319653243[/url]
[url]https://www.badcaps.net/forum/showthread.php?t=17123[/url]
And you referred to this cap and...Leave a comment:
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Re: How to identify capacitor function?
Can you recommend something to read for an overview of common PSU or LCD PSU designs, maybe walkthroughs of some specific existing PSUs?
That capacitor you asked about was a 33uF 50V low ESR in the primary side, with 12-13V across. There's only one another electrolytic in the primary, a 0.47uF 50V standard impedance, with 1.6V.Last edited by goop; 05-06-2015, 03:42 PM.Leave a comment:
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How to identify capacitor function?
This was from another thread:
How can you identify the function? What are the typical circuit stages?... -
Re: Alternatives to Samxon GF/Decon SH at 25V?
Thanks. The Panasonic FR is close, but I guess the ripple/impedance figures for the 35V version would be different at other voltages, so maybe it would be off with the actual voltage in use? But anyway, no stock.
The Nichicon HE is actually an exact match. Didn't see it at first both because of bad data in the store parameter fields, and because the 50V version not listed in any store. 35V and 63V are stocked, but not 50V for some reason.
Well, PW it is.Last edited by goop; 04-02-2015, 07:50 PM.Leave a comment:
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Re: Alternatives to Samxon GF/Decon SH at 25V?
stj, while I assume 35V would be fine too (can't say I'm an authority), polymer caps are far lower impedance, and much more expensive.
budm, 56uF is much higher than 33uF. Also 0.14R may be too far off from 0.3?
Nichicon PW looks like the best match so far.Last edited by goop; 04-02-2015, 06:27 PM.Leave a comment:
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Re: Alternatives to Samxon GF/Decon SH at 25V?
By the way, something strange I noticed. The Samxon GF 50V 33uF is rated at 0.3R impedance (6.3x11mm case). I can't find an alternative that's that low for this capacitance. A Nichicon PW with 0.43R might still do, but am I missing something? No equivalent low ESR from other manufacturers? There's no 33uF for 50V in many series, 33uF 35V goes for 5x11mm so higher impedance, etc.Last edited by goop; 04-02-2015, 08:54 AM.Leave a comment:
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Re: Alternatives to Samxon GF/Decon SH at 25V?
Thanks. Don't know if it matters, but these are about half the impedance. But mainly, they're more expensive than the KYA, KYB, and PW.Leave a comment:
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