Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

that make me confuse; there is no between voltage. voltage present on single pin ?

as far if you have:
example:
1:0
2:17v
3:17v
4:0

like that; not between. component have in and out, or as capacitors work in and ground to the other side.

example 1: ground
2 voltage in

edit: multimeter in DCV 20

black always to the metal external usb, red on each Number and report.

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Ohhh ok sorry I probably misunderstood you, I measured the voltage between (eg one probe on 1, other probe on 2). Now if I do it like you said, black on ground, usb port, i get:
1:17V
2:0
3:17V
4:17V

(So black probe on usb port, red probe on 1,2,3,4 respectively)

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

ok, 0603 ok, fuse is ok. now check that pin3 of U7000. isl6259

when i ask for voltage.... black always to metal.

edit: when u connect dc power, light become green?

if u put a working battery it become orange (if battery is a bit low)?

if u let dc in, do it turn off after some time?
with dc in, does some component become hot ?

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Thanks for your patience, haha you are really helpful. You mentioned before that the 6259 is near battery connector, but I really cannot find a component with that marking.

When I connect dc power, light becomes green when computer is put together. When I have it plugged in just the board, it is very faintly green.

If i plug it in with a battery, it does not become orange. But I could double check that if you want.

If I plug in cord, I do not think it turns off (the voltages measured stay for at least a minute, again could let it in longer)

I do not think dc plugged it anything becomes hot, but I do not leave it plugged in very long. If you want, I can leave it in for a while and then see.

EDIT:
Left it plugged in for 5+ minutes: nothing became hot, charger stayed slightly green, voltage still present

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

when i said hot i mean some component on the board (not ac adapter).

here is the i6259 marked.

pin 1 and 3 indicated.

check if 17v are present on pin3 of i625 (u7000 on the diagram)

to work mac need u7000, smc and g3hot 3.42 volt.

LT3470 is the gehot supplier, while u4900 is the smc chip.

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Pin 3 is 4.0 volts (at least my multimeter says so)

And yes, I left it plugged in, unplugged and felt the board with my hands. Everything was cold

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

4 v should be ok. next is to check for g3hot 3.42 volt.

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Do you have the diagram for this? I know apple try to keep it secret and what not, but it sounds like you have one.

Well for example the last chip isl6259 is marked on the board i625 9ahrtz f224qt, do you have any general guidelines on how to find these (i was looking for that specific combination), like to find the gehot LT3470.

This is quite a detective work But i think I am learning a lot, which is why I came here.

Btw i forgot to mention in the original post, may be of some help, with good battery plugged in, the battery indicator leds also do not show anything.

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

i have a A1278 schematic (13 inch core duo ) different layout, but similar component.

i suppose no battery indicator is u7000bad, but not sure.

lt 3470 should be near lvds socket, down right. it's small component.

edit: as i reported on another forum (i have one macbook pro 13'' A1278 ). no battery indicator, no power, nothing. i spot a short, removed the bad one by removing once a time. after short is gone, i put a new isl6259 and battery indicator is ok, g3hot is ok and mac now start (ofcourse no post since i miss one component).

maybe your battery indicator missing is bad isl625, or some short somewhere.

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Well i found this thread http://forums.macrumors.com/showthre...122338&page=32 post #782, different mac but i would think similar component, when I google the component it usually has marking LDPR 056F or something very similar, but i am not seeing anything marked that. I have been searching for boardview file for this thing, that would make things a lot easier, no luck.

Would it by any chance be one of these?
1-marked r33v t126k dhf
2-no marking
3-marked 5JR (?)


EDIT: I thought when we tested isl6259 for 4 volts that confirmed that it is good? So what you are saying is that you had a short somewhere else, but apart from resolving that you also had to replace isl6259?

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Also, idk if maybe you remember, but the isl6259 has to do with charging, right. In the original post I said that the battery that was originally in this computer was shot (only has 0.15V on it and will not charge) which sounds to me like the battery was shorted also. Would that blow the isl6259???

As I said, I suspect that the original owner (that I bought the computer from) shorted something with a screwdriver. The computer was not taken apart before me beyond the back plate (he tried to replace hard drive), which would mean that he was messing with the area of the board around battery plug and maybe all the ribbons to the left of it. What would happen if the soldered points in front of battery plug were shorted by a screwdriver?

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

not sure but lt3470 should be one of those, probably upper left.



if you have i6259ahrtz and have hot air + flux u can try replace it.

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Do you know if it is supposed to have 5 or 6 pins? Because the one on the left has 5 (can't see it in the pic, but it has only 2 pins on the other side), the right one has 6 pins. The left one (5 pins) only has marking that says 12, the right one is marked 24N6.

I do have rework station, but I do not have the part, I can buy this one
http://www.ebay.com/itm/1PCS-x-New-I...-/170922229992

I can also take the computer to Apple store for a diagnostic, idk if they would tell me exactly what is wrong

What pin should I measure on lt3470? Also, these do not have 1st pin marked so I am not sure where to count from.

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

on the schematic it say iut has 9 or more pins. so 5 or 6 is not lt3470

on ebay here is the g3hot.

http://www.ebay.com/itm/1-Piece-Bran...item2ecaf0d4e9

for the chip ill buy it from the other ebay seller. that see-ic gived me a bad stencil. it come damaged. e-best instead ship most thing with tracking.

u can look also on digikey or mouser if you live in usa.

first change that isl 625 (u7000) and let's see if u have back battery indicator. then we look for u6990 (lt3470 ).

wework machine too big for mainboard parts like that. heat gun is way better. i have a atten 8586. set it to 400° and speed to 4 . after 1.5-2 mins chip is on it's position.

a good flux is needed too. i use now mouser flux no clean.

hope that help.

ps: im on the other forum too. there are 2-3 people that know most everything about macs

Do you know if it is supposed to have 5 or 6 pins? Because the one on the left has 5 (can't see it in the pic, but it has only 2 pins on the other side), the right one has 6 pins. The left one (5 pins) only has marking that says 12, the right one is marked 24N6.

I do have rework station, but I do not have the part, I can buy this one
http://www.ebay.com/itm/1PCS-x-New-I...-/170922229992

I can also take the computer to Apple store for a diagnostic, idk if they would tell me exactly what is wrong

What pin should I measure on lt3470? Also, these do not have 1st pin marked so I am not sure where to count from.

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

What forum do you mean, macrumors? Thanks for the help, yeah i googled the gehot and looked for a part that looks like it on the board, but cannot find it, i hope it is marked. Well my rework station has hot air gun too, nothing fancy but has always worked for me. But the temp setting will come handy, thanks. I actually have something very similar to your rework station (well that is what we call rework station, solder and hot air combo)

I will prob buy new flux, i use kingbo for bigger parts, but idk if it is good for tiny parts like this. Plus it may be expired.

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

yeah, i mean macrumors. with multimeter in short mode, check all coils if are ok or not before changing any component.

i too shorted a macbook with my gold and silver bracelets :|

no i dont use metal parts with me annymore

so, first check for shorts, if all ok change u7000.

for rework machin i mean a bga station

ok for the hot air and flux.

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

hi, today i got some macbook board not working. one doesnt light up battery indicator and doesnt start. on pin 3 ov u7000 i have 4 volt like you.

i put multimeter to spot for short and i found a short in the backlight fuse , but only in one side and fuse is burned (not visible) but from one side to the other there is no closed circuit.

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Which one is that? Can you take a picture and tag it? What normally causes shorts for you? Corrosion? I know there are many issues with the backlight fuse on the macbook pro.

I actually took the computer to Apple store, they gave me a new motherboard for $300, which is still a lot less than that I would have paid for a used, working macbook.

Do you have a store or are you doing this just as a hobby?

[dellxps15]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

im learning all this sfaff to open then a repair shop. the 2 apple mainboard that arrived today are mine. i bought them to learn and to improve my solder skill

i got them for 32€ ship included for 2

one have water damaged. the other dunno, have to look better at it.

once i got also broken backlit macbook. it was just the fuse that went bad. (probably also lcd as it was not working. paid all 100€. only working mainboard will give me 200€

now im reassembling it to sell complete macbook. with that money i have other things to buy like microscope, ultrasonic cleaner and so on.


fuse is a very small brown thing with a dot on it. or white and big like the other 2.

im mean, for a non working macbook, fist we have to check for shorts on coils, then on fuses (3-4 total)

[akotalik]

Re: Macbook Pro Mid 2012 bad fuse?-Charity $$$ reward

Haha nice, I never get these great finds I do not do this too often, usually you can make decent money from it, but I just dont have time. Where did you get boards so cheap?

I bought 2 broken macbooks to keep one myself and the other I will prob give to my wife, one i fixed and the other was fixed by apple.