Thinkpad R51 fuse rating ?

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djgillery · #1 Post by **djgillery** » Thu Jun 26, 2008 2:14 am

Iv'e just recently contacted a forum member regarding a problem with my R51 in that it wouldn't run on battery power. He's directed me to straight to the source of the problem F9 open circuit, which I would now like to replace. It's a very tiny black fuse with a white letter 'F' on it, the question is what's it rating, does anyone have any idea?.

djgillery · #2 Post by **djgillery** » Thu Jun 26, 2008 9:56 am

If no info available, does anyone know of a supplier of this fuse. Does anybody have an old burn't out M/B that I could remove the fuse from ?.

#3 Post by **rkawakami** » Thu Jun 26, 2008 4:32 pm

Does your R51 fuse look like the one that is in the smaller blue circle in this picture?

http://www.rkawakami.net/ibm_t2x/t23_mo ... _fuses.jpg

If so, I think they are available from mouser.com and/or digikey.com. Both are US-based electronic component distributors. Give me a few minutes to look back through the archives...

#4 Post by **rkawakami** » Thu Jun 26, 2008 4:51 pm

Okay, going on a gut feeling that most, if not all, of the fuses on Thinkpads were sourced from Littelfuse, try looking at this .PDF file:

http://www.littelfuse.com/data/en/Data_ ... se_466.pdf

Starting at the Littelfuse home page and going through their nicely arranged search function, selecting:

by Technology: Fuses
by Problem: Short Circuit / Current Overload / Fault Current
by Industry: Consumer Electronics
by Application: Notebook Computer
by Circuit: Battery pack

leads to a page which lists the "466 Series" of fuses. That's where I found the .PDF linked above. According to the part marking system on the third page (strangely enough, labeled "5"

), an "F" code is 0.5 amp. Double check the size of the 1206 package (.12 inch x .06 inch) with what is on your motherboard.

Here's links to order them:

http://www.mouser.com/Search/ProductDet ... vy3w%3d%3d
http://search.digikey.com/scripts/DkSea ... F1454CT-ND

Not sure on their international shipping policies, but I'd suspect that you would do better to find a local supplier if you are going to be buying them new. You should be able to plug in "littelfuse 466" into most site's search functions and see if they are available.

djgillery · #5 Post by **djgillery** » Fri Jun 27, 2008 2:33 am

Thanks for the info Ray, Iv'e just ordered 10 from Farnell's in the UK. Some people seem to simply piggy back replacement fuses, it seems there's less chance of dammaging the M/B, what do you think ?.

#6 Post by **rkawakami** » Fri Jun 27, 2008 2:53 am

As long as you can insure that the contact points on both ends of the original fuse are still connected to the motherboard and that those contacts extend to the top surface of the fuse (the datasheet seems to imply that), then you should be okay. It is safer to try to attach the new fuse to the old one instead of trying to remove the old. Your de-soldering operation could lift the fragile traces of the motherboard.

djgillery · #7 Post by **djgillery** » Mon Jun 30, 2008 8:19 am

Unfortunately the fuses Littelfuse's although very small are about twice as wide and long as the one on the M/B. Iv'e manage to solder one on flying leads so I'll give it a try. Whether the 'F' rating on the fuse means the same is anyone's guess!. I'll have another look at the Littelfuse catalogue and see if I can see a smaller range of fuses and see if there lettering system is consistent throughout the ranges.

djgillery · #8 Post by **djgillery** » Mon Jun 30, 2008 8:51 am

I think its a 467 series fuse!.

http://www.littelfuse.com/data/en/Data_Sheets/467.pdf

The size looks more like it and the coding system is the same so hopefully we've found the correct rating!. I'll try it out and see.

#9 Post by **rkawakami** » Mon Jun 30, 2008 12:37 pm

Ouch, those fuses are small (0603 package)! Quarter the size of the 466 series which are 1206.

Thinkpad R51 fuse rating ?

Thinkpad R51 fuse rating ?

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