T4x Fuse Locations

[inso]

This never happened, because it's impossible to get a hold of the fuse without paying a total of $50 to get a few of them sent in a huge box via UPS or FedEx to Norway.

So I wonder if just bypassing the fuse with a wire or soldering over would work?

[poshgeordie]

So I wonder if just bypassing the fuse with a wire or soldering over would work?.

Please don't do this - the fuses are there to protect the delicate circuits and blow for a reason.

PM sent regarding sending you a couple of fuses - should be able to sort you out OK.

[inso]

A bit late, but tought I should update this for the record:


I replaced the fuse and regulator-chip according to: http://mayohardware.blogspot.com/2009/0 ... d-t40.html

You'll need thin, a soldering iron and a roll of "soder wich" to remove the old parts, and also preferably a flux pen to insert the new, (although I did it without - didn't have flux available).

For the record I don't know if the fuse alone would've solved the problem - I replaced the regulator chip as well.

And now it works

BUT! The only problem now is that the screen is very bad , as it's a regular SXGA+ screen, not an "IPS Flexview". Appearently bad screens is a common problem with the Thinkpads (to my astonishment). I also planned to buy a new X1, but the reviews disses the screen quality as not impressive at all considering the price. And it only has a standard 1366x764 option. Beyond me... as far as I'm concerned the screen is the single most important factor on laptops.

[poshgeordie]

Glad the fuse worked for you and it sounds like you've done a good job with the removal of the old one and fitting the new one.

Good link as well.

Can't help you with the screen. It may be better to make a new thread about that if you're wanting comments or help about them.

[leacris1]

I realize this topic is rather old but I was looking for the link to the PDF file and it is no longer available. Does anyone have the file and, if so, can you email it to me?

Thanks,

Chris

[leacris1]

I realize this topic is rather old but I was looking for the link to the PDF file and it is no longer available. Does anyone have the file and, if so, can you email it to me?

Thanks,

Chris

Of course, I found the information in another thread about 10 minutes after I posted this.

Nevermind.

Chris

[poshgeordie]

Sorry for the problems with the links to various docs - my ISP has deleted all the contents on FTP space they'd given me, without telling me, so I'm restoring them via server.

In the meantime here's the new T4x Fuses location:

http://www.reflowrepairs.co.uk/ftp1/T4x%20Fuses.pdf

[fasterbybike]

What a wonderful resource. I've just had to fix a problematic T43 and found that fuse F3 was blown. Nick's document helped confirm my diagnosis, and pointed me to the right fuse to check.

Fuse F3 is tiny and quite tricky to solder into place - but a dead mobo is now working

Thanks Nick

[ginahoy]

I'm grateful to Nick and other contributors to this thread. The reference document finally led me to the cause of the LCD problems on my T42, after a series of frustrating repairs. First, I replaced the inverter. A month later, the backlight bulb failed. Right after it failed I recall a noticeable white flickering light in the lower right corner of the screen accompanied by a faint popping sound. Not good. So I immediately disabled the LCD in the BIOS.

I hooked up an external VGA monitor until I was able to obtain another display assembly. To my surprise, that didn't fix the problem so I bought another one, which arrived today. No joy. What are the odds both display assemblies are bad?!

After stumbling across this thread, I checked the three LCD fuses. Turns out F7 is bad. Not surprising in hindsight given the popping sounds I heard as the bulb failed.

Ok, so to the point of my post. I've handled a soldering iron before but not for anything so tiny. I can't imagine trying to remove the old fuse, so Inso's method of piggybacking the new fuse is appealing. Fortunately, there's plenty of vertical clearance in that area. But my 15/30 watt soldering pencil seems like a sledge hammer for this type of work. I would appreciate any advice on how to avoid doing further damage!

[malch]

You need a hot air rework soldering tool. http://www.youtube.com/watch?v=vva2t21s ... re=related

The last three minutes.

[ginahoy]

You need a hot air rework soldering tool...

Thanks for the link. I wasn't planning on removing the old fuse, but that video makes it look easy, and getting rid of the old fuse might make replacement a bit easier. But my main concern (fear) is having to solder something that small.

I was looking at the Atten 8686 (2 in 1) that includes a 50W soldering iron. Maybe I can find a video on youtube that explains how to solder SMD components?

If you don't mind, I have a question. The ThinkPad system board is a bit crowded in that area. Wouldn't there be a risk that the hot air column would melt solder on an adjacent component? The smallest nozzle appears larger than the fuse itself!

[RealBlackStuff]

@malch:
such a machine is complete overkill.

@ginahoy:
you don't need such a machine, way too expensive for your one-time need!

A $10-$15 soldering iron with 20-30W and a fine tip is all you need (from e.g. the Rat Shack).
Piggyback soldering is by far the easiest way to fix that.
If you have a spare soldering tip, you can file that down to a sharp/thin shape.
Or if you do a lot of soldering (like I do), get one of these: http://www.ebay.com/itm/250941640581
I've got the exact same one, but with 6 extra, different tips.

Spare fuses can be scavenged of an old motherboard, or bought at Mouser.com

[malch]

If doing this kind of stuff is your hobby, the Atten 8686 is right up your alley.
Good tools last a lifetime and more and more boards are SMD.
If you never intend to open up a piece of hardware to see what
's wrong- then get a soldering iron from Radio Shack.Do it once.

[ginahoy]

I thank you all for the comments. I REALLY don't want to toast this board (it's not just a money issue). So it sounds like all I need is a proper sized tip. I may try to file my tip, or maybe RS has a fine point that will fit my pencil. I bought a couple of fuses last night @ mouser. Fortunately, no minimum or handling fee, just the $5 shipping cost for priority mail. I have one of those large magnifying glasses on a stand, the kind with a circular light, so that should help a lot.

[ginahoy]

Following up on my previous post, I bought the F7 LCD fuse along with a decent soldering station (Weller WLC100) and ST7 tip. Bottom line: I was unable to piggyback solder the new fuse. The components are just too small to 1) hold the new fuse in place, 2) heat the ends of both fuses, and 3) apply solder, all with just two hands. I have an old floor-standing magnifying glass, but the glass has to be about 3" above the board in order to focus, not leaving enough room work. Also, without any experience doing this type of work, I had no idea how to set the heat on the iron (scale of 1-5).

After giving up on the fuse, I tried to solder a jumper wire, figuring that if something were to ever blow the fuse again, I wouldn't try to repair again... just replace the system board. However, the pads are so tiny that they don't hold heat long enough to allow me to remove the iron, position the jumper, and apply solder (I could definitely have used a 3rd hand).

My brother has been soldering for 30 years, mostly big audio/video racks and edit suites, etc. I sent him pictures and he said he would never attempt anything like this. He recommended checking the schematics to see if I can find alternate attachment points. However, I was unable to find the schematics on the net. I read elsewhere in this forum that it's against the rules to post links to schematics. Sigh.

I'm going to see if there's someone local who can do this sort of work. Otherwise, I'll have to buy a new system board, or base unit. I'll start another thread to further advice on that.

[rkawakami]

Regarding soldering SMT fuses piggyback style: Position replacement fuse on top of existing one. Hold in place with small screwdriver, dental pick, toothpick, "take your pick" ; whatever you can do to prevent the new fuse from moving around. Apply a small amount of solder to the tip of the iron. Place the tip of the iron on ONE side of the fuse. The metal end cap should conduct heat down to the fuse already on the board and the solder should flow between the two. Allow junction to cool and then repeat on the other end. You don't/can't/needn't heat both ends at the same time, nor do you need to feed solder to the iron and fuse. If you've coated the tip of the iron with enough solder to result in a small bump or glob, that's all you really need.

An alternative method is to apply a small amount of solder on the "bottom" side of both ends of the new fuse BEFORE you place it atop the old one. Position the new fuse so that the solder bumps are touching the old fuse. Then simply heat one end until it drops down in place. Then heat the other end. It probably won't drop down as much as the first end but your goal is to melt the solder so that it bonds both fuses together

[Metallo]

Hi guys,

the topic is old but the subject is current

Well, I have to replace the F4 fuse, so I followed the instructions in the thread and purchased a couple of spare ones from Mouser.
The F4 fuse I got is definitely bigger than the one on the MB which makes it impossible to piggyback.
I have a basic 20W solder iron with a suitable tip for the job but I failed the mission at my first attempt.

1) Wouldn't be better to remove the old fuse first? There is another component next to it and does not leave much space to work.
I was thinking to remove it and solder the new fuse using two 5mm long wires so that I can compensate the difference in length.

2) Another option I was thinking of if removing the old fuse... maybe I could scratch a bit the contact area on the left (where I have more space) and extend the contact area to reach the length of the new fuse? Just an idea...

Any suggestion is very welcome!

Thank you all!
Alex

[RealBlackStuff]

F4 fuse continues on the left with a green strip to a round hole.
If you can, remove that fuse.
Gently scrape the lacquer off that green strip and the hole.
You should now have enough room for soldering a larger fuse.
If that fails, solder a small wire on each side of the fuse, then solder the wires to the fuse location.

[Metallo]

Hi!

Than you for your super-quick reply

This confirms I can attempt both my options 1) or 2). I'll try 2 first as it looks the most accurate to me.

Let's see what happens

Alex

[ginahoy]

The F7 I got from DigiKey was same size as original, but I wasn't able to solder piggyback. If I had three hands, I might have been successful

I ended up buying another mainboard for $35. I didn't mind spending the money, but I had hoped not to have to swap the boards out, which I had never done before. All ended well.

[rkawakami]

The F4 fuse I got is definitely bigger than the one on the MB which makes it impossible to piggyback.

Then I would say that you purchased the wrong fuse. If it's in a bigger package, then that could mean it has a higher current rating which is usually a bad thing. A fuse blows out because there was (or still is) a condition that requires more power than normal. Putting a high amperage fuse in the circuit could mean that when you power it up, something other than the fuse will blow.

Unless you are SURE that whatever condition that caused the fuse to blow in the first place no longer exists, then I would proceed with caution.

[Metallo]

The F4 fuse I got is definitely bigger than the one on the MB which makes it impossible to piggyback.

Then I would say that you purchased the wrong fuse. If it's in a bigger package, then that could mean it has a higher current rating which is usually a bad thing. A fuse blows out because there was (or still is) a condition that requires more power than normal. Putting a high amperage fuse in the circuit could mean that when you power it up, something other than the fuse will blow.

Unless you are SURE that whatever condition that caused the fuse to blow in the first place no longer exists, then I would proceed with caution.

I can only assume why it blew, we had multiple power outages due to bad weather conditions.
Unless the info found on the document"Thinkpad T4x Board Fuses" in this forum is incorrect, the fuse is the right one, also, the values look correct.

http://ca.mouser.com/Search/ProductDeta ... b5qiBGD4M=

Cheers
Alex

[Metallo]

Hi,

I am writing to you from my reborn T40

I succeeded to solder the F4 fuse by removing the old one, scratch a bit the contact area on the left (where I had more space) and extend the contact area to reach the length of the new fuse.

It worked very good and the computer is running as new again.

Hope this helps other users who may get in trouble with F4.

Cheers
Alex