R40 MOBO replacement

[emeraldgirl08]

Hi all. I've got a big project coming up. I believe I have a dead MOBO on an R40 2897-B4U that I picked up for $30. I do not know if the LCD is working but it's physical appearance is very good- almost new! As a matter of fact the whole laptop is in pretty decent shape. The processor is an 1.4 Pentium M. I have a spare 1.7 Banias Pentium M I would like to upgrade this laptop to.

Different than the other R40 I have- an R40 Pentium 4!

So... I'm considering replacing the MOBO. Where would I find the MOBO part number??? Is it printed on the MOBO? I have ran a check on the S/N and it comes up with nothing. The Model type does for sure but I'm not certain about the MOBO P/N. I'm not too sure if this would be a good learning experience for me or would it cause me grief?

IOW is it a difficult task to complete???

I have taken the laptop apart to get a peek at the DC jack and it's soldering to the MOBO. I noticed a weird white residue around the area and that there was a small fuse (maybe???) that was copper-colored at both ends but white in the middle. The same white color as the residue. The fuse said FU. Yeah I know it sounds funny but that's what I read on it.

Here is a pic.

TIA

[Harryc]

Never touch the FU fuse...I repeat, never touch .. LOL. Try checking the FU fuse with a multimeter, it might be blown.

[emeraldgirl08]

Ha ha! Too funny!

Seriously though I wouldn't know how to use a multimeter at all! I think I see things like that around the house... have to ask my Bf or my Dad if they can help me with that one. I don't have to plug the laptop in while using that gadget do I???

I'm really not ready to go yet!!!

lol.

[ajkula66]

Mobo FRU should be under the RAM cover...

The problem here being, parts lookup doesn't list any FRUs for the PM-based machines...

With that said, you can replace that planar with any R40 board and it will work...

[RealBlackStuff]

FU2, what funny names!

Machines with Pentium M CPU have a different mobo from the ones with P4 CPU.
Check item 17 on page 155 of the HMM.
(Ban = Banias)
Planar for Ban M6 w/ security card, w/ 1394 peak shift, 91P7858
Planar for Ban M6 w/ security card, w/o 1394 peak shift, 91P7862
Planar for Ban M7 w/ security card, w/ 1394 peak shift, 91P7283
Planar for Ban M7 w/ security card, w/o 1394 peak shift, 91P7284
Don't know the difference between M6 and M7, M6 probably the 13/14" models, and M7 the 15" (or the other way around).
1394 is Firewire connector.

[emeraldgirl08]

@RBS

This PM R40 does have the firewire so this narrows my search down! I also have a 15" screen on the PM R40.

@ajkula

I don't see any numbers that are close to the P/N that Dom put up. I only see the FRU P/N for the lid and I'm guessing the DIMM slot mechanism.

Didn't get a chance to test the fuse yet. I was a little exhausted from traveling and class yesterday and turned in early last night. If it is the fuse how hard would it be to replace it and where do I find one at? The fuse maybe a lot cheaper than buying a planar.

[RealBlackStuff]

Mouser.com or digikey.com are the major single part suppliers.
If you could find the same fuse from e.g. another defective mobo (could be T23/30/4X), you could pry it off that bad board, and solder it piggyback style over the faulty R40 FU fuse (provided there is enough room above it).

With a multimeter, you set it to 0 Ohms. Then when you touch the two cable-ends together, the meter-needle should move all the way to the right, showing there is a connection.
If you touch both ends of that FU fuse, and the fuse is OK, the needle should also pop to the right.
If not, the fuse is blown.

[rkawakami]

<snip> Then when you touch the two cable-ends together, the meter-needle should move all the way to the right, showing there is a connection.

Needle? Who uses/has an old analog multimeter nowdays? (All of you HAM operators out there need not reply)

@emeraldgirl08: If your BF or Dad has joined the 21st century and has a digital multimeter, then put the meter into the OHMS mode (symbol is: Ω). If there are ranges provided in the ohms mode, then select the lowest range (i.e., 200 or 300 ohms). When the test leads are touched together, the meter should read 0. Do the same across the ends of the fuse where there's a small metal endcap and if you also read 0, then the fuse is good. Anything more than 0 ohms means that the fuse is bad.

[SMA]

Just to inspire you to take a look around on the motherboard, I'd like to show you a picture of what I found on the motherboard in a dead R40 of mine.

Picture

[RealBlackStuff]

Who uses/has an old analog multimeter nowadays?

I have two of them actually, the older one must be at least 20 years old, and still runs only on its second AA battery!
One mustn't be wasteful nowadays!

[ajkula66]

@emeraldgirl08:

When I said "under the RAM cover" I meant on the planar itself...in that area...apologies for not being more precise. You might have to remove the DIMMs to get the sticker exposed.

[jronald]

I have an original Simpson in the black Bakelite case, granted I inherited it
Like this except more than 30 years old
http://www.tequipment.net/Simpson260-8P.asp

Ron

[emeraldgirl08]

I found it! Thanks guys!

FYI the motherboard FRU P/N is 93P3418.

I didn't see this anywhere in the HMM btw.

I've decided I will order a replacement planar for the R40 sometime soon.