Macintosh Portable M5120 Coil Choke Inductor Pulse replacement

did you check it with a meter?

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

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

Click to expand...

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 ?

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

Click to expand...

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 .

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

uniserver said:

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

Click to expand...

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

thanks UNI

ok sounds good buddy.

your meter leads are in the wrong holes!

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

techknight said:

your meter leads are in the wrong holes!

Click to expand...

Hi Techknight 

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

You need continuity check.

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

What's a good one?

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.

Thanks, good info!

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

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. 

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

Nice yeah data sheets are a beautiful thing.