If you work close to 3/5V power supply, check for any knocked off component, or damaged trace.
Pay atention for enabling signals...
Pay atention for enabling signals...
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Macbook 2009 820-2530 - no spin-up
- Thread starter jpadie
- Start date
the only major chip that was close by to where I was working was the s5 regulator (tps51125). and even that was a good 15-20mm from the area of the audio connector.
the s3_en signals come directly from the MCP though. So unless someone has a better idea I fear somehow that the MCP has fried.
the s3_en signals come directly from the MCP though. So unless someone has a better idea I fear somehow that the MCP has fried.
Q7221 is close too.
And it has few components connected on the opposite side; related with enable signal...
And it has few components connected on the opposite side; related with enable signal...
Hi again
I'm getting only 22Ohm to ground on pin 1 of L7260. has anyone got an equivalent board they can test for me to see what's normal? injecting voltage there I get some high(ish) heat on the L3405 and C3452 pair. and some heat on the two inductors l3402 and l3403. I will remove C3452 in the morning to see what difference that would make, but I'd expect closer to zero ohms for a real short to ground.
I'm getting only 22Ohm to ground on pin 1 of L7260. has anyone got an equivalent board they can test for me to see what's normal? injecting voltage there I get some high(ish) heat on the L3405 and C3452 pair. and some heat on the two inductors l3402 and l3403. I will remove C3452 in the morning to see what difference that would make, but I'd expect closer to zero ohms for a real short to ground.
I'm really getting confused by this. I suspect it is in large part because the schematic does not line up at all with the boardview files I have. I'm using drawing number 051-7546 in case that helps anyone ?
on the boardview, the pin that has the low resistance is pin 1 of L7260. On the schematic, pin 1 is connected
directly to TPS51125 (labelled as U7201 on the schematic and U7200 on the boardview) to the P3v3s5_LL pin
indirectly via an RC pair R7264/C7264 to P3v3S5_VBST
and into Q7260.
the low resistance to ground remains there even when Q7260 AND the TPS51125 are removed.
On the boardview, pin 1 is connected to all sorts of things. So it looks like the pin numbers are inverted.
Is this is a known issue with the generally available boardview/schematic pairs? I'm feeling it is not worth the time to chase a rabbit down a hole when the map of the burrow is incorrect ...
on the boardview, the pin that has the low resistance is pin 1 of L7260. On the schematic, pin 1 is connected
directly to TPS51125 (labelled as U7201 on the schematic and U7200 on the boardview) to the P3v3s5_LL pin
indirectly via an RC pair R7264/C7264 to P3v3S5_VBST
and into Q7260.
the low resistance to ground remains there even when Q7260 AND the TPS51125 are removed.
On the boardview, pin 1 is connected to all sorts of things. So it looks like the pin numbers are inverted.
Is this is a known issue with the generally available boardview/schematic pairs? I'm feeling it is not worth the time to chase a rabbit down a hole when the map of the burrow is incorrect ...
L7260 is a short in DC, like any other coil.
I suppose the low value is on L7260 pin2.
Lift one side of the coil and see where the low value remains...
I suppose the low value is on L7260 pin2.
Lift one side of the coil and see where the low value remains...
if course - as per the above, the short is on the side of pin 1. I've lifted so far the RTC, Q7940, U7200, L3405, U4800, C7291, C7290, Q4590, Q3450 and tested the resistors and other caps in the area. the low resistance remains.
Lifting resistor R7267 tells me that the problem is on the pin 1 side of that.
But nothing looks bad or burned on the board. No corrosion and, as I said, it was working fine until I 'fixed' the speaker connector just north of U7200. Evidently I've blown something downstream, but with 20Ohms it's unlikely to generate that much heat to be able to trace it.
When I'm next at the bench I will life U6200 just in case that is the culprit.
Lifting resistor R7267 tells me that the problem is on the pin 1 side of that.
But nothing looks bad or burned on the board. No corrosion and, as I said, it was working fine until I 'fixed' the speaker connector just north of U7200. Evidently I've blown something downstream, but with 20Ohms it's unlikely to generate that much heat to be able to trace it.
When I'm next at the bench I will life U6200 just in case that is the culprit.