820-2850 dim green light.

Chuck60

Member
ok so i received my new isl6259 today installed it and green light on magsafe and my voltage is 12.53 at the fuse.and i have a fan spin for like 10 seconds and turns off
then back on again. I'm gonna go over the power rails and see whats going on i will report back to you. tomorrow. Thank you
 

Chuck60

Member
Ok I?m back on this board so I?m no longer getting 12v. Charger light is green but no 12v it?s been 1.6-4v the few times I?ve checked. No short on either side of chip. I have 3.3v and 3.42 and isl has 5v1_chrg_vdd
 
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2informaticos

Administrator
Staff member
Post diode mode on PPBUS_G3H power rail.
Check all resistors around ISL6259 for proper values.
Post again the same voltages for U7000 above mentioned.
Also exact ohm resistance between pins 17/18 and 27/28.

Be sure to have good solders!
 

Chuck60

Member
Thank you your guidance help me find the culprit. I found the issue with fluctuations on g3h it was r7005.

so now I?m back on the fan spinning for 20 sec and stopping the usb mouse and usb stick flash when the fan spins and stops when the fan stops. G3h is stable 12.53v and 5v pulses with power on off
 
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TCRScircuit

Super Moderator
Staff member
If you hold the power button down when it is doing this, does it start up normally?


My very first board repair would do this, and you held the power button down, and it would start normally, ended up being a bad ISL.

Had another machine that would do this, and power on normally if the power button was held, and it was a short on a trackpad subrail.

Try it and report results. If the same, check for a short on S0 and S3 rails.
 

2informaticos

Administrator
Staff member
If the USB stick flashes, means the board is working in that time.
Check if board stays on if you start in SMC bypass mode.
Be sure heatsink is properly fixed and CPU/GPU don't get overheat fast.
 

Chuck60

Member
If you hold the power button down when it is doing this, does it start up normally?


My very first board repair would do this, and you held the power button down, and it would start normally, ended up being a bad ISL.

Had another machine that would do this, and power on normally if the power button was held, and it was a short on a trackpad subrail.

Try it and report results. If the same, check for a short on S0 and S3 rails.
Ok I tried to hold the power button on power up it has no affect whatsoever :/ I will try to go over the power rails again
 

Chuck60

Member
If the USB stick flashes, means the board is working in that time.
Check if board stays on if you start in SMC bypass mode.
Be sure heatsink is properly fixed and CPU/GPU don't get overheat fast.
It does the same pulsing but with fan spinning at maximum or fast on then off. On then off
thank you for your help
 
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TCRScircuit

Super Moderator
Staff member
This will likely suck.

Recheck current sensing on pins 17/18 27/28 of the ISL should be 3-5 ohms / 20 ohms.

Also, resistance to ground on CPU and GPU VCORE.
 

Chuck60

Member
This will likely suck.

Recheck current sensing on pins 17/18 27/28 of the ISL should be 3-5 ohms / 20 ohms.

Also, resistance to ground on CPU and GPU VCORE.
Yes 27/28 is 20 ohms 17/18 is 3.8 ohms I notice something strange looking around u6100 I saw on a resistors smc_batlow_L fluctuating with power on its goes up to 4.9 and off but I have no battery plugged in. To my understanding it only goes high when a battery is plugged
thanks for your help
 

2informaticos

Administrator
Staff member
Do NOT quote an entire post visible few centimeters above.
Please, maintain forum aesthetic!

Check if you get voltage on all big coils.
 

TCRScircuit

Super Moderator
Staff member
SMC batlow should go high with a battery or the use of a 85w charger. 4.9v isn't right. That is a 3.3v signal. Are your meter batteries low?

That reminds me. Are you using a real 85w charger with this?

When the fan spins, does PLT_RESET_L go high?
 

Chuck60

Member
SMC batlow should go high with a battery or the use of a 85w charger. 4.9v isn't right. That is a 3.3v signal. Are your meter batteries low?

That reminds me. Are you using a real 85w charger with this?

When the fan spins, does PLT_RESET_L go high?
Yes plt_reset_L =3.3v
yes it?s a real 85w charger
 
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2informaticos

Administrator
Staff member
I really don't understand why you still continue to quote entire previous posts :(.

Your board starts on charger only.
That means PM_BATLOW_L was and is still high; no need to check that.
But you refuse to check what I asked two posts before...
 

Chuck60

Member
I?m sorry I only found 1 fluctuating L7330
im sorry I never measured directly on the inductor before I alway look for a large cap near by for voltage. Maybe I haven?t learned enough yet. I also found pulsing on c5932 pin 1 0v to 3.3v right next to u5450 and c7921 cap is OL
 
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