A1304 2009 820-2375 no fan

[VinceLx]

Hello,
I have this board in good conditions, no liquid damage visible.
Green light on charger, a battery charges, but no fan.

SMC_RESET_L=3.44V
PPBUS_G3H=8.4V
SMBUS_SMC_BSA_SCL=3.43V
SMBUS_SMC_BSA_SDA=3.43V

It manages to charge a battery, current 0.8A, with BATT_POS=8.4V
SMC_BC_ACOK=3.43V
CHGR_VDD=5.1V
PM_SYSRST_L=3.36V

PP3V3_S5=3.36V
PP1V05_S5=1.12V

Where to check to set PPBUS_G3H to 12.6V?

 

[piernov]

PPBUS_G3H at 8.4V is fine. Power button must be triggered for machine to turn on. If it doesn't turn on go through the list of power rails.

 

[2informaticos]

Post exact ohm resistance to ground at 3V42_G3H rail.

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.

 

[VinceLx]

Sometimes I feel so stupid... it turns on with power button, thank you both. Because A1237 turns on alone when connecting the power supply, I thought A1304 would be the same... they are "almost" identical.
Anyway, now fan spins, it chimes, LCD backlight on, but no blinking folder, either on internal or external displays.
There is USB activity, at the beginning steady LED switched on then blinking after 45 seconds.

PP3V3_LCDVDD_SW_F=1.1V
PP3V3_S0_LCD_F=3.4V
PP3V3_S5=3.4V
PP3V3_LCDVDD_SW=3.4V so I assume L9004 is not good, it does not look nice, I will change that tomorrow and tell you the result

 

[piernov]

A1237 has Intel GMCH/ICH while A1304 has NVidia MCP.

 

[VinceLx]

Ok thanks. All these names were not clear for me, I found an interesting link to understand them:

Northbridge (computing) - Wikipedia

en.wikipedia.org

But ok, NVIDIA needs power button.

Replacing L9004 solved the issue, now blinking folder.

I read a comment from Louis in the link below that macbook air (a1237/a1304) should be avoided. Can you tell me their weak points? Up to now, I see that the LVDS cables are fragile, anything else?

Getting started - from a biz standpoint (already have some knowledge and most equip.)

So, hey everyone :) I decided to sign up for the forum to get some info and contact with other professionals in this field. A little introduction. I type fast so forgive my wordiness. I own a small electronics design and manufacturing company in Massachusetts. I am an electronics designer...

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