Sceptre x22wg-Gamer 22" LCD

[mockingbird]

Re: Sceptre x22wg-Gamer 22" LCD

Good work, but Darn!!! I would have expected one of those voltages would be incorrect, they are all reasonable. I was hoping for a shorted regulator.
Check the resistance between pin 48 of the Pericom IC and the right hand pin of U7 (the one that is at 4.97 volts).

I made a mistake before and I measured Pin 25 (VD0) and you wanted 48 - VDD. But now I looked at the datasheet and I can tell which it is. No worries though, because the measurement is exactly the same.

Regarding the resistance check... Which Ohm setting should I have the meter at? Also am I correct in assuming that common probe will go on the regulator and red probe on pin 48?

[PlainBill]

Re: Sceptre x22wg-Gamer 22" LCD

I made a mistake before and I measured Pin 25 (VD0) and you wanted 48 - VDD. But now I looked at the datasheet and I can tell which it is. No worries though, because the measurement is exactly the same.

Regarding the resistance check... Which Ohm setting should I have the meter at? Also am I correct in assuming that common probe will go on the regulator and red probe on pin 48?

Use the lowest ohms setting. As a general rule, always use the lowest range which will give a meaningful reading. In other words, if you are measuring and unknown resistance you MIGHT start at the 20 Megohm range. If you get a reading of 0001 you should reduce the range to the 2 Megohm, 200 Kohm, etc until you get a reading like 000.3.

PlainBill

[mockingbird]

Re: Sceptre x22wg-Gamer 22" LCD

Thanks. I appreciate your patience. What about polarity, does it matter which probe goes where? Because I am getting different readings in reverse.

[PlainBill]

Re: Sceptre x22wg-Gamer 22" LCD

Thanks. I appreciate your patience. What about polarity, does it matter which probe goes where? Because I am getting different readings in reverse.

That is significant. Let me give a little background here, and explain my thought processes.

The datasheet for the Pericom IC indicates the maximum supply voltage is 3.3V. The voltage you are measuring is essentially the same as the input voltage to the logic card, 4.97 VDC. There are two possible reasons for that:

1. Either deliberately or in error the supply voltage to the Pericom IC was connected to the 5V rail. As a matter of faith I believe a designer will NEVER intentionally release a design which will kill an IC. However, mistakes do happen. Also, it is possible that Pericom has upgraded their design and the IC can now operate from 5 Volts. Neither of these are likely, hooking an IC designed for 3.3 volts to a 5 volt supply will result in an early (spectacular) failure; there is no reason to allow operation from 5 VDC.

2. The regulator supplying the 3.3 VDC to the Pericom IC has failed, and is supplying 4.97 VDC instead. Note that the output of LDO (low drop out) regulators will typically be at least 1 Volt below the input voltage. This implies that the regulator is shorted. But I believe I have identified all regulators, none are shorted.

So to eliminate possibility 1, I had you check the resistance from the 5V supply to the supply input of the Pericom IC. And you seem to be saying there is no short. So once again I am wondering WTH is going on?

Just to preserve my sanity, please check the resistance from ground to pin 1 and to pin 48 of the Pericom IC. Also check the resistance from 5V to pin 1 and pin 48. If reversing the probes gives different readings, report both readings.

PlainBill

[mockingbird]

Re: Sceptre x22wg-Gamer 22" LCD

I'm finding it very difficult to take resistance readings from the IC to the regulator, because it keeps fluxtuating wildly on my DMM, an at any setting or polarity, my DMM shows a "-" before the number.

But here are the results for ground to 48 and 1, black on ground and red to the IC:

Pin 1: 43
Pin 48 : Nothing

[nathias]

Re: Sceptre x22wg-Gamer 22" LCD

Any luck getting the dead DVI port working again?

[mockingbird]

Re: Sceptre x22wg-Gamer 22" LCD

No, I have a feeling that Bill was correct when he said:

1. Either deliberately or in error the supply voltage to the Pericom IC was connected to the 5V rail. As a matter of faith I believe a designer will NEVER intentionally release a design which will kill an IC. However, mistakes do happen. Also, it is possible that Pericom has upgraded their design and the IC can now operate from 5 Volts. Neither of these are likely, hooking an IC designed for 3.3 volts to a 5 volt supply will result in an early (spectacular) failure; there is no reason to allow operation from 5 VDC.

Considering Sceptre has a near 100% failure rate on the DVI ports of this series, it seems to me they lazily designed it defectively.

[notajoo]

Re: Sceptre x22wg-Gamer 22" LCD

Ok, I was out of town for a week or so for the holidays. I'm back now and about to try to order the new caps I need. I found a near perfect match for the medium caps I listed earlier on the thread, but it has a lower impedance by quite a bit so I wanted to check first and make sure it would be okay to use. I browsed the threads that retiredcaps posted earlier but couldn't find anything about what acceptable amounts were for impedance differences between original and replacement caps.

My original cap is 1200 ripple and .076 impedance according to the manufacturer documents I found. The replacement is 1240 ripple and .041 impedance. The dimensions and other specs match near perfectly, and the faqs on the forum here say it's okay for ripple to be higher, but I can't find anything about acceptable impedance differences. Thanks in advance for any help provided.

[retiredcaps]

Re: Sceptre x22wg-Gamer 22" LCD

The dimensions and other specs match near perfectly, and the faqs on the forum here say it's okay for ripple to be higher, but I can't find anything about acceptable impedance differences.

Lower ESR is better. See PCBONEZ talk about it here

https://www.badcaps.net/forum/showpo...30&postcount=7

[notajoo]

Re: Sceptre x22wg-Gamer 22" LCD

Ok, so ESR and Impedance is the same thing then? When looking on digi-key and mouser it lists the ESR and Impedance in separate columns so I just assumed it wasn't the same thing. I did see the term used interchangeably on a few posts here on the forums, but when I googled it I couldn't find any information regarding what the difference was between the two terms, if any.

So now that raises another question (of course ). That post says only around 30% lower is normally acceptable and the change between the two I'm looking at is about 46%. Will I be taking a significant risk by using the new caps because of that? It's the only available cap I can seem to find that will match the uf and voltage with dimensions that will fit on my board, so I'm really hoping it will be acceptable to use.

[retiredcaps]

Re: Sceptre x22wg-Gamer 22" LCD

Ok, so ESR and Impedance is the same thing then? When looking on digi-key and mouser it lists the ESR and Impedance in separate columns so I just assumed it wasn't the same thing.

I'm looking at digikey's Panasonic FM datasheet at



I only see impedance and no separate column for ESR.

That post says only around 30% lower is normally acceptable and the change between the two I'm looking at is about 46%. Will I be taking a significant risk by using the new caps because of that?

PCBONEZ is the expert, but some other members here are less exacting about choosing replacements when it comes to ripple and ESR including myself. Sometimes you cannot find datasheets for the "old series" or the right sized cap, so you approximate.

[notajoo]

Re: Sceptre x22wg-Gamer 22" LCD

Yeah, I can't actually find the exact cap for capxon that I'm replacing. The one I'm looking at is 10mm wide rather than the 8mm mine is, but everything else seems the same so I went with that.

Also, what I was referring to about there being separate columns is when you actually use the search function on digi-key. Most of the ESR ratings are blank though in the listings as are many of the impedances. The ones that do show both ESR and impedance have different values in each column, so they aren't the same thing it seems.

I'm having no luck at all when trying to find an acceptable difference in impedances between caps so I'm thinking I may just have to order these ones since they are the only ones with specs that seem close at all and just hope that it works.

[RogueEvo]

Re: Sceptre x22wg-Gamer 22" LCD

HI all, I am new to this forum, I discovered it via google for what seems to be a fairly common problem. I have a Sceptre x22WG-Gamer 22" LCD and it has stopped working, When i try to power it on, the blue LED illuminates, and then shuts off and the LCD "clicks" as it goes off, then the LED flashes as if in sleep mode, clicking every time in goes out.

So i have read about the cap problem, and decided to take it upon myself to open up the LCD (i work for a high custom PC company and felt comfortable opening it) , On my Power Supply Board i have the same problem as the original poster, my caps match his caps from photo #5, I am curious as to a few things ....

#1 Does this indeed sound like what is wrong

#2 After reading the article found here https://www.badcaps.net/forum/showthread.php?t=2280 i have become a little confused as to WHICH cap i need, i am left with these 2 options when choosing FM/Panasonic/470uf/25v as options for search and am unsure as to which cap is correct...

http://search.digikey.com/scripts/Dk...name=P12389-ND

or

http://search.digikey.com/scripts/Dk...name=P12388-ND

We have a guy who does our soldering at work, so i just wanna get him the right parts and have it done correctly the first time if possible, Thanks so much for any help you can give me and for the over abundance of information that can be found here.


Sean

[PlainBill]

Re: Sceptre x22wg-Gamer 22" LCD

HI all, I am new to this forum, I discovered it via google for what seems to be a fairly common problem. I have a Sceptre x22WG-Gamer 22" LCD and it has stopped working, When i try to power it on, the blue LED illuminates, and then shuts off and the LCD "clicks" as it goes off, then the LED flashes as if in sleep mode, clicking every time in goes out.

So i have read about the cap problem, and decided to take it upon myself to open up the LCD (i work for a high custom PC company and felt comfortable opening it) , On my Power Supply Board i have the same problem as the original poster, my caps match his caps from photo #5, I am curious as to a few things ....

#1 Does this indeed sound like what is wrong

#2 After reading the article found here https://www.badcaps.net/forum/showthread.php?t=2280 i have become a little confused as to WHICH cap i need, i am left with these 2 options when choosing FM/Panasonic/470uf/25v as options for search and am unsure as to which cap is correct...

http://search.digikey.com/scripts/Dk...name=P12389-ND

or

http://search.digikey.com/scripts/Dk...name=P12388-ND

We have a guy who does our soldering at work, so i just wanna get him the right parts and have it done correctly the first time if possible, Thanks so much for any help you can give me and for the over abundance of information that can be found here.


Sean

1. Yes, the symptoms indicate bad capacitors.

2. PROBABLY either will work. The difference between the two is the form factor - one is taller, but has a smaller diameter. Use the one that fits. Speaking from experience, it is embarrassing when you discover a cap won't fit into the available space, or (worse), you can't get the cover back on.

PlainBill

[Mikeley]

Re: Sceptre x22wg-Gamer 22" LCD

For more technical insight into ESR, impedance, lifetime and so on see http://www.rubycon.co.jp/en/products.../technote.html

In particular look at the third section 'Performance of Aluminum Electrolytic Capacitor'. There is a pdf that can be read.


I also downloaded the attached doc from that site to help select capacitors depending on application.

ML

[notajoo]

Re: Sceptre x22wg-Gamer 22" LCD

Thanks very much for the link, but I'm neither an electrician nor a mathematician, so I have absolutely no clue what those pdfs are talking about. This is my first time messing with anything on a circuit board and the only reason I considered doing it at all is because it seems like a simple fix to desodder some caps and sodder new ones in.

Since the specs are fairly easy to find and compare online, I don't have nor need a full understanding of how it all works and the details of everything listed in those pdfs. Really I just need to know if the impedances I posted are an acceptable difference apart for replacement caps, but as I said before, I think I'm just going to order them and go with it. Worst case I'm out about $9, best case I repaired a $200+ monitor for $9. :P

[Lew]

Re: Sceptre x22wg-Gamer 22" LCD

Hello everyone. Thanks for all the friendly expert help and guidance you guys give.

I too have the Sceptre X22WG-Gamer with the FSP050-2L02 power board bad capacitor problems. I'm not an electronics expert but am handy enough with a soldering iron that I think I can get this done.

Before I order my capacitors, my question is, should I go ahead and order replacements for the blue ceramic dipped C111 and C112 capacitors with the white gunk oozing around them (and the others like the coiled ones I've shown in the attached photos) or should I just replace the C551 and other bulging radial electrolytic capacitors (like the ones included in the eBay kit)?

I don't know enough about this to know if that ooze is normal or what.

Thanks!

Lew

[seanc]

Re: Sceptre x22wg-Gamer 22" LCD

The white gunk is glue, not electrolyte. Nothing to show that those components have failed.

Do you actually have any bulging capacitors?

[Lew]

Re: Sceptre x22wg-Gamer 22" LCD

The white gunk is glue, not electrolyte. Nothing to show that those components have failed.

Do you actually have any bulging capacitors?

Thanks Sean. Yes. The CapXon 470uF 25v C551 and C552 are definitely bulging. C554 and C664 don't show anything obvious.

Neither of the Taicon 16v 1000uF 637(M) capacitors show any bulging on the tops, nor does the little CapXon 33uF 35v.

[seanc]

Re: Sceptre x22wg-Gamer 22" LCD

You're best to replace them all, including the small one, following the recommendations in this thread.
If the large capacitor isn't bulged, you can leave it alone.