SCL/SDA voltage and diode mode to ground.
I recommend to try your battery with other board too.
I recommend to try your battery with other board too.
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MacBoo Pro Early 2015 820-4924-A
- Thread starter Mario Yiannakou
- Start date
Mario Yiannakou
New member
SCL and SDA seem to be jumping around within the range 3.43 to 3.33 V. So I get 3.43 one second then 3.33 / 3.39 /3.34 /3.41 etc
These readings are without battery.
SCL 0.499 V Diode Mode
SDA 0.497 V Dode Mode
I'm sorry but I don't have another board.
Thnx M
These readings are without battery.
SCL 0.499 V Diode Mode
SDA 0.497 V Dode Mode
I'm sorry but I don't have another board.
Thnx M
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Pulsing SCL/SDA could be sign of I2C signals from SMC.
In this case, the battery is first suspect.
Don't waste more time, untill get a known good battery to test.
Just post Q7155 voltages, charger w/ and w/o battery connected
In this case, the battery is first suspect.
Don't waste more time, untill get a known good battery to test.
Just post Q7155 voltages, charger w/ and w/o battery connected
Mario Yiannakou
New member
Should there be pulses on SCL/SDA or should it be a constant voltage and if constant what voltage should I expect to see? 3.43?
Also were the diode measurements I gave you a good sign or bad sign?
If we put the battery aside for now why do you think I don't get fan spin with no battery and just charger unless I bypass the SMC?
Also were the diode measurements I gave you a good sign or bad sign?
If we put the battery aside for now why do you think I don't get fan spin with no battery and just charger unless I bypass the SMC?
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Ooops, still not starting from charger only?
Are you 100% sure using original Apple charger 85W?
Of course no fan, as normal behaviour on this board.
Fan spins later, after CPU gets hot.
Are you 100% sure using original Apple charger 85W?
Of course no fan, as normal behaviour on this board.
Fan spins later, after CPU gets hot.
Mario Yiannakou
New member
Yes proper charger
yes I know about the fan not spinning until cpu warms up
you didn?t answer my questions in my last post?? Well? I need you super skills of deduction
yes I know about the fan not spinning until cpu warms up
you didn?t answer my questions in my last post?? Well? I need you super skills of deduction
Proper test of I2C protocol for SCL/SDA lines can only be done with o-scope.
Should see something like in attachment.
Diode mode on SCL/SDA lines shouldn't show more than 1% difference for a good board; in fact is likely less than 0.5%.
"why do you think I don't get fan spin with no battery and just charger unless I bypass the SMC?"
You just told being aware of no fan spin at start.
On SMC bypass mode is normal that fan spins at max from start.
Should see something like in attachment.
Diode mode on SCL/SDA lines shouldn't show more than 1% difference for a good board; in fact is likely less than 0.5%.
"why do you think I don't get fan spin with no battery and just charger unless I bypass the SMC?"
You just told being aware of no fan spin at start.
On SMC bypass mode is normal that fan spins at max from start.
Attachments
Mario Yiannakou
New member
Sorry I don't have an oscilloscope.
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