To provide further assistance with fault finding on T4x motherboards, I've created a diagram showing every fuse location on a generic T4x board.

I'm not sure what board I originally used, but at least one fuse I found on another board is not physically on the board but has been marked up on the diagram.

The diagram can be downloaded from here.

I would like assistance to add a value and manufacturers part number to every fuse, and where they can be purchased in the USA and UK (because that's where I come from!).

I also want to give a brief description on the purpose of each fuses, and the symptoms when each fuse is open circuit (blown).

Also please check the diagram and get back to me with errors, additions, further information, locations of some of the unknown fuses etc.
Also any volunteers to help with some of the work above.

Many thanks to the numerous unnamed posters who supplied fuse information throughout the forums, including a pencil drawn diagram which prompted me to do this.

<EDIT 01 Mar 2009>

1. Added information supplied by SMA.
2. Added new page with RS, Farnell / Newark, and Mouser Catalogue numbers.

Many thanks to SMA for your information.

<EDIT> 15 mar 2009>

1. Updated fuse values - forgot to do it in Ver 2.

(Diagram Version 3 15 Mar 2009)

to start this off:

F11, F12 Littlefuse and possibly 448 series

Part number 0448010.MR (where M= 1000 off; R Reel or Tape)

Had a break with the letter values on the others from Bourns

RATING CURRENT (A)
F = 0.50
• = 0.75
K = 0.80
L = 1.00
M = 1.25
P = 1.50
N = 1.60
S = 2.00
T = 2.50
3 = 3.00
U = 3.15
W = 4.00


From Littlefuse:
.250 D
.375 E
.500 F
.750 G
001. H
1.25 J
01.5 K
1.75 L
002. N
02.5 O
003. P
03.5 R
004. S
005. T
007. W
008. X




BTW - who are the major electronics retailers in USA for this sort of thing?

<EDIT> added letter value details

In the USA: http://www.digikey.com , http://www.mouser.com and http://www.jameco.com

Suppliers for Europa can be http://www.rs-components.com and http://www.farnell.com

thanks for that SMA - where did you get that information from?

Re RS / Farnell, I use both but wasn't too sure how international RS especially was. Farnell is worldwide via New...(sorry brain fade but you know the one I mean!)

Also Farnell has a better range of SMD fuses as well.

Edit <Newark!>

Since F5 and F14 cannot be found, that unmarked one could be one of these two?

I think you're right, and it could also be F6 as well.
I'm not too keen in assigning nomenclatures to fuses which aren't marked on the board due to the 12 in 3 error possibility.

First, the original sys board photos from 91P7993 = T40.
The 'Unknown' fuse is from FRU 93P3512 = T41.

Neither are listed on the HMM

Listed System board FRU's from the HMM's for T4x:

T40:
91P7701, 91P7704, 91P7707, 91P7710, 91P7713, 91P7716, 91P7719,

T40P:
93P3304

T41:
93P3307, 93P3310,

T41P:
93P3313

T42:
93P4156, 93P4157, 93P4158, 93P4159, 27K9907, 27K9908, 27K9909, 27K9910, 27K9911, 27K9912,

T42P:
Nothing Listed.

T43:
39T0324

There's a huge task here, but if anyone has one of the above FRU's could you have a look for fuse variations.

Many thanks!

I just made it up based on my notes from a previous repair.


According to this topic the F2 fuse marked FU is a Littelfuse 7A fuse.

F11 and F12 is actually marked LF10A


Since there are only 5 different fuse types in question, I believe it would be smarter to maintain a separate tabel with the part numbers, instead of repeating the part numbers for each fuse.

The RS number for the size 0603 'N' fuse is 131-555
The RS number for the size 0603 'F' fuse is 131-557

Beware that suppliers may change their part numbers over time.

Thanks for all the replies and information.

Also sorry that I've not yet had time to update the documentation, but work is V busy at present.
I'll try and find time over the weekend.

Anyone have any more information?

Diagram updated to Version 2 (see post 1) with the following additions:

1. Corrections to existing pages.

2. New page added with RS, Farnell / Newark, Mouser Catalogue part numbers.

A special mention to SMA for a lot of detailed information and identifying errors in Ver 1.

TO DO:

A detailed check of the manufacturers and catalogue numbers. I realise that some of the fuses are not the same as the originals, but should be suitable drop in replacements. Please could someone check these out.

The Mouser catalogue numbers are for reels of fuses rather than individual ones. Are the RS and Farnell / Newark ones OK for the USA or are there better suppliers?

A number of fuses appear to be resettable types - e.g F1. They seem similar to Bourns MF-MSMF series but I cannot find a supplier for these. If anyone knows one, or knows a better replacement, please could you let me know.

Any other suggestions, corrections etc as well.

Thanks also to everyone else who has contributed as well!

Updated diagram to insert fuse values.

Now Ver 3

Hi, thanks for sharing. This is very useful data.

Good job !
Thank you !

Fuse F4 is the Fan
Please add in the table.

Thanks for that.

This is now very out of date and needs an urgent overhaul but I've no time to do it.

Also the original Master Doc was deleted with no backup so it needs to be re-done from scratch.

Is there anyone out there with a bit of spare time and who can do diagrams on Word?

I've got all the original top and bottom motherboard photos and the individual fuses pictures, so what will need to be done is to create a Word doc (I did it all on Open Office), add the circles and arrows, text boxes etc, and the tables in the normal way.

I'll supply all the updated information or maybe ask you if you could check some of the suppliers yourself - I'll give guidance as to where to check etc and can do this for you if it's too difficult.

PM me if interested and let me know your Word experience etc.

Thanks in advance, and your reward will be to be added as co-author of this immortal diagram!

I'm pretty sure I downloaded and saved that PDF on my PC.
I'm away from home till Sunday night, but I'll check when I get back.

Edit: on my laptop I just downloaded it from your link. So it's still there...

Thanks RBS, I've got the PDF OK but not the original Word doc that I made it from. I converted from .doc to PDF using the Open Office Export PDF function.

I'm sure there are better ways to do this but that seemed the easiest to do at the time!

Enjoy your time away.

Volunteer found with many thanks (you know who you are!), and the updates should be done in the next 7 - 10 days.

Alternatively if there is someone else who is very keen to give it a go, still get back to me. The person who has volunteered I know is very busy and I'm sure will be fine if someone with time on their hands and the necessary skills can help.

Many thanks already and in advance too!

Someone with a full-blown PDF program could probably make a .DOC out of it again in seconds...
You don't need any reverse-engineering.

I did try one some time ago and it completely messed everything up. Bottom line was that it was going to be easier to start again. Bottom, Bottom line is that I should have backed up the original .doc.....

If anyone can successfully reverse engineer the pdf, please let me know ASAP.

Nope - "Failed to convert" message!

Hi guys!

After much searching and asking in other forums, I stumbled over this thread and it seems like you're onto exactly what I need.

There schematics and all are nice, but unfortunately doesn't make much sense to me, because I don't know how to measure these regulators, where to begin etc. as I have very limited knowledge about circuit board electronics.

Could anybody please present this info in a user friendly way so that anybody with a voltmeter at hand could follow and diagnose where the problem is and what needs to be replaced?

I would hate to have to shill out hundreds of dollars on a new laptop when I have a perfectly working machine here that just has a AC-in problem. I cannot afford a new thinkpad, and I love the keyboard and the & 4:3 1400x1050 screen, I have a docking station for it etc.

The problem:
After coping with a bad DC-connector for a while, my Thinkpad T43 ran out of battery for good earlier this year. That means: yes, it did work from battery until it ran out, but it would no longer recharge - neither from the AC port on the laptop, or via my DOCKING station which thus eliminates a bad power-jack. This indicates that something related to the power regulator is blown, probably triggered by some short-circuiting of the wires in DC-jack.

Edit: btw yes I have also tried another power-supply, same problem.

It's quite simple.
Using a multimeter or voltmeter, set it to "continuity". Most modern multimeters will beep if you put the two probes together.
Now put one probe at each end of a fuse. If that beeps, it means the fuse is OK. If not, the fuse needs to be replaced.
Of course you do this testing with AC adapter and battery removed!

Hello again!

It's been a while, but now I've finally measured the fuses with a multimeter in "continuity" setting like "RealBlackStuff" mentioned.
It so happens that F2 is dead. Which makes sense in correlation to the list "SMA" posted above, which shows F2 is



Since my sympthoms were that the lap is working on battery, but doesn't recharge neither via the yellow power-plug or via docking station - I guess they both pass the F2?
The incident that blew the fuse probably happened when I used a bad AC adapter tip in the yellow DC plug on the back of the lap. It worked for a while even if there were some sparks because of shorting between the + and - wires, but at one point the eneviteble happened and it kicked F2's *****Expletives removed by Moderator*****

Before I consider replacing the fuse (by soldering it on top i suppose) - could I safely verify that it will solve the problem by sticking a wire on both sides of the F2 to bypass it and see if the lap recharges?

I don't think that is a good idea

The fuse limits the current, a small wire doesn't

You have the risk burning/frying your motherboard

Well, it would be preferable to find out if the fuse is the only problem before I invest time and money into replacing it, as it's somewhat hard to order ONE small resistor anywhere.

1.
I did some searching and found this thread about a guy with a similar problem, that bypassed the F2 fuse with an ammeter to see if replacing it would make his t42 work.
viewtopic.php?f=2&t=89035&hilit=regulator
I quote:


So then I'll just go ahead and set my multimeter in position "200mA DC" (???) and put the measuring sticks on both sides of the F2 while AC powersupply connected, the fuse will then be bypassed, and the battery will recharge if F2 is the only problem?


2. Plan of attack if I get it to work:


I guess I'll have to be really careful since the whole ting fries if I hold the tip on it for more than .3 seconds. Think I'll just set out for a sloppy cold solder so it barely sticks with no risk of frying, since my soldering iron isn't really all that.

200mA isn't enough. You will need to use a different meter. Here is a link to Sears. If you look at the picture it shows clearly what you need. Most meters I have seen that do amp measurments like you discribe are rated at 10 amps. I suppose there is a chance your meter will do it, you just didn't see the fine print by the female jack. I hope this helps

http://www.sears.com/shc/s/p_10153_1260 ... ockType=G4

Good luck

Micro

So I replace the fuse by simply putting a bit of lead on both ends of the fuse, then place it on top and give it a small touch with the soldering iron..

But first I need to get a hold of the F2 fuse..
What should I search for? The fuse paper in this thread only states it's a: Littelfuse 7A

What more than 7A should I ask for to find one?
Does anyone know of a store that ships internationally for a low price?

This is what you need: http://no.mouser.com/ProductDetail/Litt ... WmZtoW8%3d

From Mouser in Norway!