820-3330-b Dead to the world

[crea2k]

Hi, so I was brought this mac, its got a 820-3330-b board inside. The customer said that it had no backlight, but when I try and turn it on its totally dead. Im presuming this model runs fine off the charger with a flat battery ?.
This thing is pretty much out of the ark, so its quite different to the newer boards I have been repairing so far.
I see this model doesnt seem to have a ISL chip on it, does it just have the SMC that deals with all of the power etc ?

 

[JohnB8812]

It for sure has an ISL6259. Start by measuring the basic 3v42 PPBUS etc. Also does it turn on from just the charger no battery plugged in? If not, tried known good DC in board? MUST use 85 Watt Mag 1 btw 60 watt won't work.

 

[crea2k]

Thanks, iv just found it on the power page of the schematic, so its not as alien as I thought, il try the usual steps and update this.

 

[crea2k]

Ok so these were taken at u7000 with just the charger plugged in and battery not plugged in:

CHGR_AGATE - 0.003
PPCHGR_DCIN - 16.75
CHGR_ACIN - 4.01
CHGR_VFRQ - 3.261
CHGR_ICOMP -1.268
CHGR_CELL -3.372
CHGR_VCOMP - 0.982
CHGR_VNEG - 1.7 - 2.08 jumping around
CHGR_AMON - 0.029
SMBUS_SMC_5_G3_SDA - 3.370
SMBUS_SMC_5_G3_SCL - 3.370
PP3V42_G3H - 3.373
CHGR_RST_L - 3.343
SMC_BC_ACOK- 3.232
CHGR_BMON - 0.068
CHGR_BGATE - 12.41
CHGR_CSO_N - 12.55
CHGR_CSO_P - 12.55
PP5V1_CHGR_VDD - 5.50
PP5V1_CHGR_VDDP - 5.50
CHGR_LGATE - 0.643
CHGR_PHASE - 12.55
CHGR_UGATE - 13.43
CHGR_BOOT - 17.31
CHGR_SGATE - 15.42
CHGR_CSI_N -16.47
CHGR_CSI_P - 16.48
GND_CHGR_AGND - 0

 

[JohnB8812]

Ok so I would assume you have a green light and 12.56 volts on PPBUS_G3H? If so, is it turning on with just the charger or is it dead? If dead, keep measuring your voltages to see what is missing.

 

[crea2k]

Yes green light, but not turning on, no fan spin. Which other voltages should I be looking for ?, iv not come across a no power one before so not sure what should be there to boot. PPBUS_G3H is 12.55

 

[JohnB8812]

Just making sure you have a known good 85 watt mag 1. Is PPBUS 12.56 volts? If so, check to see that PPVRTC_G3H is a steady 3.3 volts. Then go through your S5/4/3/0's

 

[crea2k]

Ok.......so I left it plugged in with the battery plugged in and all of a sudden its suddenly turned on, even though it wasnt running off the power supply alone. So now im back on the no backlight problem. If I shine a torch through the apple I can see the screen, so going to look at that problem now.

 

[JohnB8812]

Ok so does it start from both the charger and the battery? If so, then yeah next thing is to check backlight.

 

[crea2k]

It doesnt start from the charger by itself, but that could be a crappy charger, but I only have one of the lower power ones for testing things (the one it came with is the 85w one), but I dont have another 85w one anyway.

 

[JohnB8812]

Ok definitely get another charger before you send it back to avoid any returns! ALWAYS use 85 watt chargers to test things. As far as the backlight goes, check voltage on PPVOUT_SW_LCDBKLT with the screen attached.