Help identify an SMD part on T23 motherboard *pic*

Message

Bizzy · #1 Post by **Bizzy** » Fri Jul 18, 2008 9:22 pm

I own a T23 (2647-8MU) which developed a problem about 6-8 months ago similar to the wavering fan issue, except my fan never changed speeds, it just locked up or blue screened on me. Eventually it got to where it wouldn't boot up or pass the posts at all, but it did start giving me a beep code; 1-3-3-1.

I purchased some new memory hoping that it was faulty ram causing the problem, but that wasn't it. Today I opened it up, just for giggles and grins to see what I could see. Below is a picture of what I found. There is an enlarged area in the upper right corner of the problem area, I think it's a SM capacitor, but am not sure at all on that. I was told that it is is a capacitor for the power supply section of the motherboard but I'd like find out the specifics of the part so I can buy another one to replace it. The pic linked below is slightly larger than 50k allowed here so I will just post a link to it rather than displaying the image.

I have searched and searched for a BOM listing or the PCB artwork and found nothing. I really want to try and fix this board myself and I can't justify buying a new board without at least giving it a go. I was hoping that maybe someone here could help me identify this particular part.

Many thanks in advance!

Beth

Click to see the picture

#2 Post by **rkawakami** » Sat Jul 19, 2008 1:44 am

Welcome to thinkpads.com!

You've come to the right place in your search for documentation on T23 motherboard components

. Unfortunately, there does not appear to be any documentation (official or otherwise) or a build-of-materials (BOM), circuit schematics or sources for replacement parts. We are left with doing some reverse-engineering and plain old detective work.

I've got one of my spare T23 boards in my hands and you are correct in saying that those two parts are capacitors. They appear to be part of the battery charging circuit due to their location next to that large inductor (marked L7). If the one on the left of your picture inset has shorted, it will probably cause some grief with the power system. I'll have to disconnect and measure them with a capacitance meter but I can't do it right now. Expect a reply in the morning (unless somebody else beats me to it). Two sources for components like this are Mouser.com and DigiKey.com. They tend to sell single-unit quantities but the shipping is what really hurts.

I started a thread awhile back which would be perfect for updating when I get a definitive answer as to what the capacitance of these two are:

http://forum.thinkpads.com/viewtopic.php?t=37956

In my topside picture, these parts are located at G6.

#3 Post by **RealBlackStuff** » Sat Jul 19, 2008 8:08 am

Before ordering new parts, check the inductor right above it.
Last week I got a T23 with that very same inductor badly solderered.
That was the first time I came across a bad inductor in that spot.
Normally it's the ones on the bottom that fall off.

Bizzy · #4 Post by **Bizzy** » Sat Jul 19, 2008 9:34 am

rkawakami wrote:Welcome to thinkpads.com!

You've come to the right place in your search for documentation on T23 motherboard components . Unfortunately, there does not appear to be any documentation (official or otherwise) or a build-of-materials (BOM), circuit schematics or sources for replacement parts. We are left with doing some reverse-engineering and plain old detective work.

I've got one of my spare T23 boards in my hands and you are correct in saying that those two parts are capacitors. They appear to be part of the battery charging circuit due to their location next to that large inductor (marked L7). If the one on the left of your picture inset has shorted, it will probably cause some grief with the power system. I'll have to disconnect and measure them with a capacitance meter but I can't do it right now. Expect a reply in the morning (unless somebody else beats me to it). Two sources for components like this are Mouser.com and DigiKey.com. They tend to sell single-unit quantities but the shipping is what really hurts.

I started a thread awhile back which would be perfect for updating when I get a definitive answer as to what the capacitance of these two are:

http://forum.thinkpads.com/viewtopic.php?t=37956

In my topside picture, these parts are located at G6.

Thanks for your reply and welcome. With all the other helpful info that's here I knew I had found the right place to ask questions. I saw your other post with the topside/bottomside images. I'm glad that you took the time to do that for people, I'm sure it's been a great help to many, myself included.

It has been many years since I worked in the electronics field, so I wasn't sure what the part was for certain. I assumed given its location next to the inductor that it was a capacitor. Back in the day when I did this type of work, it was thru hole technology so I'm learning as I go along with the SM parts.

If I can find out what the value is of the capacitor I had planned on getting a replacement part from either Mouser or DigiKey as they do carry parts by the piece.

Being as the two parts are so close together, I wonder if it would be wise to go ahead and replace both the capacitors since the one failed and perhaps replace the inductor as well. The board doesn't seem to be "burned" per say, but I do see some scorching from when the capacitor popped.

In your opinion, this is probably a ceramic capacitor? I believe that it is just based on how the popped one looks, but again, I have very little experience with SM parts so my eye is untrained in that respect.

Also, when replacing the part, I have seen that some people would use a thin tipped soldering iron which is not a problem for me, but what about solder paste and a heat gun? Would that work as well as a soldering iron?

Thanks again for all the help.

#5 Post by **rkawakami** » Sat Jul 19, 2008 12:49 pm

RealBlackStuff wrote:Last week I got a T23 with that very same inductor badly solderered. That was the first time I came across a bad inductor in that spot.

When this inductor is loose is seems to cause a problem with charging the battery. The system will operate from the main battery but no charging occurs.

#6 Post by **rkawakami** » Sat Jul 19, 2008 1:54 pm

Bizzy wrote:Being as the two parts are so close together, I wonder if it would be wise to go ahead and replace both the capacitors since the one failed and perhaps replace the inductor as well.

Probably is a good idea to replace both capacitors. The inductor, maybe not needed. If you have an ohmmeter, simply measure the resistance between the two lead (metal tabs on the sides) and you should read very close to 0 ohms. If you get anything higher than that, the coil is open and you will need a new one.

Bizzy wrote:In your opinion, this is probably a ceramic capacitor? I believe that it is just based on how the popped one looks, but again, I have very little experience with SM parts so my eye is untrained in that respect.

I would say that it is a multilayer, ceramic capacitor, based upon the size.

Bizzy wrote:Also, when replacing the part, I have seen that some people would use a thin tipped soldering iron which is not a problem for me, but what about solder paste and a heat gun? Would that work as well as a soldering iron?

If you have access to that equipment then that would be the preferred method. Just make sure that the components in the surrounding area are not disturbed. I was able to remove both caps with my el-cheapo 23W Radio Shack iron and could probably re-attach them since they are so large (figuratively speaking when considering the sizes of some of the resistors and fuse nearby).

After removing both caps and measuring them with my meter, they both appear to be 5uF in value. So, based upon the look and the measured size of these parts, this would be my best guess as to what you can use:

Type: Multilayer, surface mount ceramic capacitor
Value: 4.7uf (this is a standard value and close enough to 5uF)
Voltage: 50V (estimating 16V max in circuit; could probably use 25V spec'ed part but I like using at least double)
Case: 1210 (inch) or 3225 (mm)

enter: 81-GRM32R71H475KA88L in the search box at mouser.com
enter: 490-1864-1-ND in the search box at digikey.com

Both sites sell this Murata 4.7uF 50V SMD cap (mfg part number: GRM32ER71H475KA88L) but Mouser allows single unit quantities, while DigiKey has a 10 piece minimum order.

ref: http://www.practicalcomponents.com/draw ... rawing.htm (surface mount ceramic capacitor package styles)

Bizzy · #7 Post by **Bizzy** » Sat Jul 19, 2008 2:12 pm

Thank you so much!!!! I'll see about ordering the pieces this afternoon and I will keep you guys updated on how things turn out.

Thank you! Thank you! Thank you!

Edit: I think I will order an inductor just to be on the safe side since I don't know for sure whether or not the one on the board is good. At least that way it will be here if it's needed.

#8 Post by **rkawakami** » Sat Jul 19, 2008 2:35 pm

That inductor should be the one in this post:

http://forum.thinkpads.com/viewtopic.ph ... 384#294384

Current part number appears to be: CDRH104RNP-150NC (15.0uH)

Bizzy · #9 Post by **Bizzy** » Wed Jul 23, 2008 5:48 pm

Well, I ordered the parts and received them in today. Prior to removing the old cap I noticed that it appeared to be loose which wasn't a good sign to me. So I removed the old cap and sure enough, the landing was pulled up from the board.

I've done work with circuit boards in the past, but with thru-hole technology so I hoped that it might be the same where the contact could be fixed. I guess it's not the same with SM boards though. Not holding my breath, I soldered the new cap back into place and put the laptop back together again. Nothing. But at least I can say that I tried.

So.....does anyone have a decent T23 2647-8MU motherboard for sale?

#10 Post by **RealBlackStuff** » Thu Jul 24, 2008 7:09 am

You can use any T23 motherboard.
The 26P8218 can sometimes be found under the older P/N 26P7997.
Otherwise a 12P3770 will work every time.
If you get a new/used mobo, you need to change the stored type-number to match your laptop's TYPE.
For this, you need the Maintenance program, which you install on a floppy:
ftp://ftp.software.ibm.com/pc/pccbbs/mo ... tm23us.exe

Bizzy · #11 Post by **Bizzy** » Thu Jul 24, 2008 8:27 am

Thanks for that info. I did locate a used 26P8218 motherboard on FleaBay for a decent price. I shouldn't have to change the stored type number on this one should I? I downloaded the file you linked just in case. If I do have to change that, can it be done from CDrom instead of floppy? I don't have a floppy drive on my laptop.

Thanks again for all your help. I will get this laptop back in working condition yet! If it hadn't been such a decent machine in the past I wouldn't even bother messing with it.

Edit: Well shucks. The seller of the board I bought found that it had problems, so I'm looking again fro another board. *sigh*

T23FUN · #12 Post by **T23FUN** » Wed Aug 13, 2008 12:15 pm

Beth,
I just caught up on your posts. I am curious how things worked out. I like my T23 too and have spent hours getting it going after some issues, but not a mother board.
I looked at the pictures of your board and the smoke definitely was let out somewhere. I fear that if the capacitor shorted it would take with it a number of parts.
Well wishes that you find a solution without too much personal energy spent. Another thread on this forum said T23's should go between $100 and $200 but then you have spare parts.

Good Luck!
Rich

Help identify an SMD part on T23 motherboard pic

Help identify an SMD part on T23 motherboard pic

Who is online