Thread

Macintosh Portable M5120 Coil Choke Inductor Pulse replacement

68kMLA Hardware 18 posts Jul 13, 2015 to Jul 15, 2015

#1 Mon, 13 Jul 2015 - 20:18 68kMLA

Hy Everybody

someone can help me, i'm not in the position to finding in Italy the same inductor PULSE PE-53082 8946 IP that has been damaged, I can not find the datasheet and I ask to you if you know a replacement part with the same characteristics

thank you !!

#2 Mon, 13 Jul 2015 - 20:42 68kMLA

did you check it with a meter?

#3 Mon, 13 Jul 2015 - 21:14 68kMLA

Ciao!

Why do you think that the inductor is bad? is it open? usually it is very hard to measure inductance with a multimeter. It might lead you to think that the component is shorted.

From what I remember, the inductor is part of a DC-DC "Boost"converter circuit, the main chip is a LT1070, looking at its datasheet, it looks like it uses a 150uH axial inductor.

At this point, I did a quick search on RS (a large component supplier in Italy), and I found this: PE-52645NL.

I am not sure that the PE-53082 is a 150uH inductor, in power supply designs, they usually choose a slightly higher inductance value than the one recommended by the datasheet.

Once I get some free time, I will look at Portable Board and I will try to find a similar replacement part.

EDIT: maybe this one or this one are suitable replacements, I found this document that lists all of the models from Pulse

#4 Mon, 13 Jul 2015 - 22:22 68kMLA

Ferrix97 said:
Ciao!

Why do you think that the inductor is bad? is it open? usually it is very hard to measure inductance with a multimeter. It might lead you to think that the component is shorted.

From what I remember, the inductor is part of a DC-DC "Boost"converter circuit, the main chip is a LT1070, looking at its datasheet, it looks like it uses a 150uH axial inductor.

At this point, I did a quick search on RS (a large component supplier in Italy), and I found this: PE-52645NL.

I am not sure that the PE-53082 is a 150uH inductor, in power supply designs, they usually choose a slightly higher inductance value than the one recommended by the datasheet.

Once I get some free time, I will look at Portable Board and I will try to find a similar replacement part.

EDIT: maybe this one or this one are suitable replacements, I found this document that lists all of the models from Pulse

Hy Buddies!

Very hard to do with Meter, mine is not the best , testing i report these values as in pics attached

I've broken inductor legs desoldering it ( don't ask me why i've done it! I'm a real As..hole)

Grazie Ferrix i'll get in touch with you in italian ( my english is not so good) !

Thanks Uni for your availability any suggestion about ?

#5 Mon, 13 Jul 2015 - 22:30 68kMLA

Ferrix97 said:
Ciao!

Why do you think that the inductor is bad? is it open? usually it is very hard to measure inductance with a multimeter. It might lead you to think that the component is shorted.

From what I remember, the inductor is part of a DC-DC "Boost"converter circuit, the main chip is a LT1070, looking at its datasheet, it looks like it uses a 150uH axial inductor.

At this point, I did a quick search on RS (a large component supplier in Italy), and I found this: PE-52645NL.

I am not sure that the PE-53082 is a 150uH inductor, in power supply designs, they usually choose a slightly higher inductance value than the one recommended by the datasheet.

Once I get some free time, I will look at Portable Board and I will try to find a similar replacement part.

EDIT: maybe this one or this one are suitable replacements, I found this document that lists all of the models from Pulse

Hi Ferrix have you recapped macintosh portable original ac adapter?

I have followed your videos on you tube and repaired 3 powerbooks 100 adapter ( of 5 not working)

My Macintosh portable ac adapter is not working stable , now i use an aftermarket 1,5 amp but i'd like to repair the original one

maybe the capacitors references are the same .

#6 Mon, 13 Jul 2015 - 22:52 68kMLA

Ah, i see.. i have an extra i can send you, maybe i can throw it in a parcel back to you?

#7 Mon, 13 Jul 2015 - 23:06 68kMLA

uniserver said:
Ah, i see.. i have an extra i can send you, maybe i can throw it in a parcel back to you?

Keep it! Asap i'm considering to send you some MB to repair

thanks UNI

#8 Mon, 13 Jul 2015 - 23:10 68kMLA

ok sounds good buddy.

#9 Mon, 13 Jul 2015 - 23:51 68kMLA

your meter leads are in the wrong holes!

#10 Tue, 14 Jul 2015 - 09:17 68kMLA

I have never opened a Macintosh Portable Power Supply (because I don't own one), but I think it is repairable.

You can also tweak a PowerBook 100 PSU to work with a portable, there is a current adjustment trimmer inside.

I'll send you a PM (in Italian) soon

#11 Tue, 14 Jul 2015 - 12:09 68kMLA

techknight said:
your meter leads are in the wrong holes!

Hi Techknight

thank you , i have tried also in other holes but the only values i registered were those, not the right instrument .

#12 Tue, 14 Jul 2015 - 12:47 68kMLA

You need continuity check.

Plus that meter is a piece of crap anyway. You need a good one.

#13 Tue, 14 Jul 2015 - 12:56 68kMLA

What's a good one?

#14 Tue, 14 Jul 2015 - 13:16 68kMLA

I usually recommend Fluke Multimeters, but they are quite expensive, about 100€ for an entry level auto-range model.

If you are on a budget, you can get a UNI-T or Mastech for less than half the the price of the Fluke. just make sure they are auto-ranging meters.

some meters are also able to measure inductors and capacitors, but usually this feature doesn't work that well.

#15 Tue, 14 Jul 2015 - 14:29 68kMLA

Thanks, good info!

I'm also searching for a multimeter with very thin tips to measure the tiny connectors of PRAM batteries.

#16 Wed, 15 Jul 2015 - 00:51 68kMLA

Also another thing that will help here is a B&K Precision or the like LCR meter. that will measure the inductance and the Q rating of the coil.

If I am not mistaken, I believe those measured out to be about 150uH.

#17 Wed, 15 Jul 2015 - 09:28 68kMLA

150uH is the inductance value recommended in the LT1070 datasheet for a 5V to 12V DC-DC Boost Converter

They also recommend this inductor, but it is way bigger than the one mounted on the portable.

But in the inductor's datasheet, they also specify a "C" size that matches with the size of the inductor in the portable, but they only go up to 100uH

#18 Wed, 15 Jul 2015 - 22:07 68kMLA

Nice yeah data sheets are a beautiful thing.