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Old 04-29-2020, 04:48 AM   #1
nickBcap
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Default 20 pin 8A on HP 250 G4 mb - voltage regulator?

Trying to find the correct replacement part for this IC.
I think it is a 3-5V voltage regulator and I have two motherboards with the same part with only the first figures to go by (8A) to locate the replacement. I can not identify its type either.
8A 2K F3Q is one number and; 8A 3D (U (or) V /2K) so U2K or V2K.
Measures 3mm x 3mm.
Component is on the underside of the motherboard.
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Old 04-29-2020, 05:55 AM   #2
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Its a Richtek RT8243AZQW

https://www.richtek.com/assets/produ...8243ABC-07.pdf
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Old 04-29-2020, 09:52 AM   #3
nickBcap
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Wow, thank you but this is the wrong type. The original is a QFP, possibly VQFP ? with the pins on the outsides of the chip. But I can check this part number out and look for options. Thanks very much.

Last edited by nickBcap; 04-29-2020 at 09:57 AM..
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Old 04-29-2020, 10:05 AM   #4
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Is the motherboard a compal la-c811p.Post some pictures of the IC .
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Old 04-29-2020, 10:14 AM   #5
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Now going by your find and what I need, this is the nearest QFN type I can see on Ebay, but not sure of the soldering technique nor the exact specs.
RT8243A RT8243AZ RT8243AZQ 8A=EC 8A=EF 8A=xx RT8243AZQW WQFP 3x3-20 IC Chip.
Thank you for this.
I will post pics tomorrow. 4:14am here.
a link - https://www.ebay.com/itm/5pcs-RT8243...AAAOSwUEVYDyH8
Sorry, I am tired here now, I also saw a same QFN 3x3 mm same dimensions as what I have to replace.

Last edited by nickBcap; 04-29-2020 at 10:17 AM..
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Old 04-29-2020, 04:20 PM   #6
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Hi, some photos.
Both boards have these identical model numbers revision and date of manufacture.
The motherboard is from an HP 250 G4 model number:
AHL50 / ABL52 LA-C7701P Rev: 1.0
2015 - 09 - 15
I hope the links to my One Drive work ok.

https://1drv.ms/u/s!Ap7-liQx-miLmLdZ...KBuOA?e=tyYXNo
https://1drv.ms/u/s!Ap7-liQx-miLmLda...GKfbA?e=SNtLes

Last edited by nickBcap; 04-29-2020 at 04:23 PM..
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Old 04-29-2020, 05:03 PM   #7
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

The ic is a RT8243AZQW
Product code = 8A
Date code:
YM = 3D 2K
DNN = U2K F3Q

It is a QFN-20
You will need hot air to remove and replace the ic because it has a ground pad in the middle.
Attached Files
File Type: pdf RT8243.pdf (314.1 KB, 48 views)

Last edited by R_J; 04-29-2020 at 05:09 PM..
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Old 04-29-2020, 07:30 PM   #8
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Hi, thank you but I am hoping to find a chip with the identical pins as the original IC.
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Old 04-30-2020, 03:26 AM   #9
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Quote:
Originally Posted by nickBcap View Post
Hi, thank you but I am hoping to find a chip with the identical pins as the original IC.
It is the chip you need,there are NO legs on it,what you can see around the outside is solder.
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Old 04-30-2020, 04:32 AM   #10
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Ok thank you, I went and bought the chips anyway thinking to try the solder technique for the first time.
The two boards have different problems but are showing the same one symptom, 3 blinking CAPS key LED's at power on, but it is not the slow or fast blinks indicating a corrupt bios problem, it is the other way around either 3 slow or fast LED blinks.
So this is my first attempt at component type laptop motherboard problem solving beyond capacitor replacement repairs
Fortunately I found a YouTube video about this motherboard today which I did not find when earlier searching.
Thank you for the help.
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Old 05-06-2020, 09:20 PM   #11
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

In the photo the Coil R15 550 090 in the yellow circle is hot @ 64degrees celsius and the resistor (I think it is) 220uF 2R5 C47 to the top of the coil in the picture is hot and also the small chip V1525 CN036 to the left of the Coil is @ around 36Deg.

And what I seem to have learned is that any chip on a motherboard that is getting hot like this should be replaced, but I only started looking for a motherboard repair course.

Last edited by nickBcap; 05-06-2020 at 09:33 PM.. Reason: adding link to photo
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Old 05-07-2020, 12:54 AM   #12
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Bear in mind that things get hot when a significant current is going through them. A coil is one of those places where a short is less likely than it would be in an IC, and it getting hot may be suggesting a problem elsewhere.
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Old 05-07-2020, 01:46 AM   #13
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

I had realized that yes, and maybe the decision to buy the RT8243A chips was hasty.
I am catching up with repair course now and waiting to when I understand what I am doing before I make any repairs.
I do notice however two MLCCs - Multilayer Ceramic Capacitors nearest the charging port are not showing any reading in Continuity mode.
I need to find out if they are supposed to behave differently when the motherboard is powered on.
When I test most even the tiniest MLCCs there is a O.L. beep in Continuity Mode but when I test the two there is no OL beep in Continuity mode and it is the same for quite a few others.
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Old 05-07-2020, 01:47 AM   #14
nickBcap
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Quote:
Originally Posted by emestee View Post
Bear in mind that things get hot when a significant current is going through them. A coil is one of those places where a short is less likely than it would be in an IC, and it getting hot may be suggesting a problem elsewhere.
The Link I tried to post as an https: link does not appear to me in the Post previous to the Quoted post. What could be the reason for this?
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Old 05-07-2020, 03:41 AM   #15
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Hi, right by the power charger port is a Dual Uni-Directional ESD Protection Diode which is shorted, I get no O.L. Beep like I do most of the capacitors and the other Dual Uni-Directional ESD Protection Diode near to it.
I have searched and came up with a possible substitute and also I notice there is comparable of the same component on Ebay which are much cheaper.
Can you tell me is the two components are compatible I can post the original first then the possible replacement and a link to Ebay where possible cheaper replacements might be.


http://www.ebay.com/sch/i.html?_from...OT-23&_sacat=0

Last edited by nickBcap; 05-07-2020 at 03:43 AM.. Reason: Links to my One Drive to pdf files there are not showing in the Post.
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Old 05-07-2020, 03:45 AM   #16
nickBcap
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Can someone tell me please, why the Links to my One Drive to pdf files there are not showing in the Post. They have appeared in my previous posts. I thought the problem may be the https: prefix so I changed it to http: link prefix.
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Old 05-07-2020, 04:53 AM   #17
nickBcap
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Here is the Link to the two PDF files of the two Double ESD protection diodes in
SOT23 - I hope the link appears in the post.
https://1drv.ms/u/s!Ap7-liQx-miLmpNr...F17vQ?e=WXmCZQ
Code:
https://1drv.ms/u/s!Ap7-liQx-miLmpNrGSv6spkLNF17vQ?e=WXmCZQ
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Old 05-07-2020, 05:08 AM   #18
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Quote:
Originally Posted by nickBcap View Post
I am catching up with repair course now and waiting to when I understand what I am doing before I make any repairs.
I do notice however two MLCCs - Multilayer Ceramic Capacitors nearest the charging port are not showing any reading in Continuity mode.
I need to find out if they are supposed to behave differently when the motherboard is powered on.
When I test most even the tiniest MLCCs there is a O.L. beep in Continuity Mode but when I test the two there is no OL beep in Continuity mode and it is the same for quite a few others.
Capacitors are not supposed to ring. At best, they should produce a very short ring while they're charging. If they beep continuously, you are looking at a short. Capacitors are often organized in parallel networks of differing capacitance, so a short in one of them (or whatever their inputs are attached to) would show as a short in all of them. You determine what is shorted by injecting voltage and watching for heat-up.

I want to emphasize: capacitors not ringing isn't a problem, yes ringing is.

Last edited by emestee; 05-07-2020 at 05:29 AM..
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Old 05-07-2020, 05:12 AM   #19
emestee
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Quote:
Originally Posted by nickBcap View Post
Hi, right by the power charger port is a Dual Uni-Directional ESD Protection Diode which is shorted, I get no O.L. Beep like I do most of the capacitors and the other Dual Uni-Directional ESD Protection Diode near to it.
[/URL]
A beep means the current is running between the probes. In the diode testing mode, a functioning diode will let the current through one way only, and the DMM will show you a voltage drop of 0.4-0.7 volts. If you switch the probes in the opposite direction you should get the O.L. indication, as the diode blocks the current.

If that is not happening (diode rings with probes connected both ways) you are looking at a short. If the DMM shows O.L. with probes connected both ways, you're looking at an open fault. In the former case, whether it is the diode itself that failed will depend on circuits around it. In the latter, you can be pretty much sure it's the diode.

O.L. stands for open loop - the DMM is not supposed to ring when it is displayed.

Last edited by emestee; 05-07-2020 at 05:34 AM..
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Old 05-07-2020, 04:20 PM   #20
nickBcap
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Default Re: 20 pin 8A on HP 250 G4 mb - voltage regulator?

Quote:
Originally Posted by emestee View Post
A beep means the current is running between the probes. In the diode testing mode, a functioning diode will let the current through one way only, and the DMM will show you a voltage drop of 0.4-0.7 volts. If you switch the probes in the opposite direction you should get the O.L. indication, as the diode blocks the current.

If that is not happening (diode rings with probes connected both ways) you are looking at a short. If the DMM shows O.L. with probes connected both ways, you're looking at an open fault. In the former case, whether it is the diode itself that failed will depend on circuits around it. In the latter, you can be pretty much sure it's the diode.

O.L. stands for open loop - the DMM is not supposed to ring when it is displayed.
Thank you for the plain English explanation.
The first Dual Uni-Directional ESD Protection Diode, 3-Pin SOT-23 before the first MLCC is shorting and also the MLCC is shorting. But somehow power is getting to the second Dual Uni-Directional ESD Protection Diode and to the rest of the board. Trying to make sense of the motherboard schematic pdf.

Last edited by nickBcap; 05-07-2020 at 05:12 PM..
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