a1278 emc 2351 bios needed ,

[highpulse]

i there, i got this MBP on the bench not turning on , i got orange led but not charging , charger is working fine , but computer not turning on or charging battery , even removing battery , computer still not turn on . Cheked bios this bios is a 4mb file , any clues ?
also if anyone have a good dump for this model i apreciate.

[highpulse]

Re: a1278 emc 2351 bios needed ,

just a few changes !
the charger led is always green , once i press the battery cheker button on the left side of the chassi , there is no green led on the charge indicator . and computer does not turn on . im not use to work much on macs , but electronics is pratically all the same , but if you got a few tips were to search more first , would be nice . cheers

[highpulse]

Re: a1278 emc 2351 bios needed ,

well cheking well tps 51125 , notice that i dont have any kind of VREG or VOUT or even entrips .. alltough the battery chek is now showing the led when i press the button . but no indication of charge.
Vin on the 51125 is around 12.58 volts.

[highpulse]

Re: a1278 emc 2351 bios needed ,

btw tps was replaced and same issue

[highpulse]

Re: a1278 emc 2351 bios needed ,

cheked the motherboard , and didnt find any code , unless in the magnetic jack 820-2565-A ,

weird issue , yesterday somehow , when noticed that vreg was really low like 0 , when i pressed the battery chek button , and was now displaing only one led blinking(drained battery) but no charge or any kind of activity once i apply the dc power . cheked that , after a few retrys i got VREG 3 and 5 0.40 and 0.96 , entrips i got 0 , EN0 got 0 , Vout got around 0.40 , not normal , but im a bit stuck here to be honest , anyone with some skills to helpo me out on this one?

thk in advance

[highpulse]

Re: a1278 emc 2351 bios needed ,

820-2879-b board reference

[dellxps15]

Re: a1278 emc 2351 bios needed ,

common mainboard. if you connect battery only, bil (battery indicator light) works ?


post all voltage of u7000 (isl6259 near left bottom side of ram in the place u have lvd connector.)



if you have green light means g3hot is ok.

[highpulse]

Re: a1278 emc 2351 bios needed ,

no the light indicator is not working , but yesterday somehow he worked for a while(light indicator) but also vreg were at 0 volts on 51125
my board is diferent , i dont have the board file for this board , so finding it the u7000 will be fucked up , since there is no id's i will take a picture of my board both sides for you can help me out

[highpulse]

Re: a1278 emc 2351 bios needed ,

found the u7000 will make measurements now and will post now the following values

1- 0,01 - 0,13
2- 16,25
3- 3,96
4- 3,39
5- 1,19-1,25
6- 3,39
7- 0,35
8- 1,91-2,00
9- 0,03
10- 2,38-2,58
11- 2,38-2,58
12- 2,38-2,58
13- 2,38-2,58
14- 2,23-2,41
15- 0,08
16- 11,43-12,6
17- 12,31
18- 12,31
19- 5,08
20- 5,06
21- 0,25
22- 0
23- 12,3
24- 12,66
25- 16,50
26- 15,92
27- 16,16
28- 16,17

does are the values i got on the ISL

[highpulse]

Re: a1278 emc 2351 bios needed ,

The light indicator works , i just received another mac alltough 1 year after model , i removed the battery from the non working one , and start charging it on the other mac , and it charged around 50% , i removed the batter and reinserted on the not working mac , when i press the batteyr power indicator , it show that i got around 50% battery , but once i insert the magnetic dc jack , i notice that the led start blinking (like charging) but it blink only 3 times , then no more blinks . alltough if i remove the battery from the mac , and leave only the dc jack , the led is orange ,, if i put the battery back on , the led stay green ..... but it does turn on , with battery or with dc jack or with both !

[dellxps15]

Re: a1278 emc 2351 bios needed ,

volt on pin 12 g3hot is low. it should be much near as 3.42volt. post volt on u6990.

u can find it with .brd.

u7000 get hot or had some corrosion ?

psu is fully working ?

volt on g3h pad in pic ?

if u short g3h+gnd macbook boot ? (place fan to see if it boot)
look image and report volt or value of resistor and component marked.

edit: image edited so look again.

[highpulse]

Re: a1278 emc 2351 bios needed ,

i there mate , so u7000 is cold , and there is nothing hot on the board ,

regarding the values on the g3hot pins i got the same value 1.68v , and when shunting both pins nothing happen (drop to 0 ) .

pins for u6990

1 - 1.65
2 - 3.39
3 - 7
4 - 3.40
5 - 0
6 - 16.15
7 - 0
8 - 16.15

[dellxps15]

Re: a1278 emc 2351 bios needed ,

looking your voltage with coil, check also R6995 and R6996 if correct

on a working g3hot 3.38volt i have
1.22 (should be 1.25)
3.38
6.92
3.39
0
16.2
0
16.2

so all seems ok. just pin 1 is a bit higher.

check those resistor r6995 r6996. if ok remove L6995 and post back U6990 voltage.

edit: up you said on u7000 pin 12- 2,38-2,58 volt, so u sure on g3hot pad show in picture u have only 1.68 ?

[highpulse]

Re: a1278 emc 2351 bios needed ,

R6995 i got 1.30 volts on the left side and on the right side 3.40 (directions seen on .BRD) R6996 0 volt on left side , 1.32 on right side .


on u7000 now i got on pins 12 and 13 3.40volts ... this machine is really incostant with values .
btw the resistors r6995 and r6996 are ok on they ohmic value .

yes the g3hot pad give me the 1.63 volts

[highpulse]

Re: a1278 emc 2351 bios needed ,

after removing l6995

1 - 0.70
2 - 0
3 . 13.85
4 - 15.40
5 - 0
6 - 16.58
7 - 0
8 - 16.58

noticed that also i lost vin for tps 51125 , only having 0.91 volts (this after removing the coil)

[dellxps15]

Re: a1278 emc 2351 bios needed ,

this l6995 is the g3hot 3.42volt. without that u wont get green light and pc is dead.

without coil u should have:

0.56
0.24
10.64
13.76
0
16.04
0
16.04


as u see on pin 3 something is not perfect dont understand why u have 3.4 volt on pin 12 of u 7000 and only 1.63volt on that g3h pad.

try to put keyboard and make a smc reset (hold power botton down for 10 second without any power.

[highpulse]

Re: a1278 emc 2351 bios needed ,

well there are incredible things , after removing and resoldering the coil now i got 3.40 on the G3HOT pin , but i got a inconstant value on vin of tps 51125 , or i have 12.60 volts or its start droping now slowly but then its with 12.60 again ... but still TPS getting no values at all ,

[highpulse]

Re: a1278 emc 2351 bios needed ,

ok also another problem , i got the g3hot pin value of 1.66 once i have the keyboard ribbon cable connected to board , if the ribbon is not connected then i got 3.40 , but even if i shunt it wont turn on ..
Also stating that if the keyboard ribbon is connected i got at least SMALL but some voltages on the TPS 51125 ... its not attached pratically all is 0

[dellxps15]

Re: a1278 emc 2351 bios needed ,

plug in psu, put back heatsink, put fan, remove keyboard.
on the back check 3.3 and 5volt coil if volts are present.

if 3.3 present, try short g3h and gnd pad.

[highpulse]

Re: a1278 emc 2351 bios needed ,

on the picture you sent , you asked me to give you some value , so here they go , the first mosfet got 16 volts on both sides , the 2 resistors near the u7000 , does resistor are r7010 and r7011 , and the voltage values are

R7010 4.06 left side , and 17 volts right side of the resistor arounk 30K ohm
R7011 4.04 left side and 0 volts right side , around 9.3kohm (cheked with schematic and both ohm values are correct.

for TPS51125 , like i mentioned with keyboard ribbon i got some values , without ribbon i got outher values