[SOLVED]820-3462 IC0R error

[bridportpcrepair]

Hi guys, long term lurker, first time poster / subscriber here!

I've got a Macbook 2013 Retina here (820-3462) that presents with a laggy trackpad and slow operation, kernel task up at 700% etc.

Board was very clean, very small amount of liquid ingress (possibly coffee on one of the Poly caps underneath) but no corrosion and (seemingly) no damage done, or at least nothing obvious.

Running ASD gives me an IC0R error (I can get the error code if required but the L/B is on the shelf at the moment). Battery is charged to 100% and seems good.

Have investigated the IC0R circuit, all traces look good and test fine, all components in the circuit test at their specified values.

U5400 voltages:

Pin 1 / 2 - GND
Pin 3 - 3.3v
Pin 4 / 5 - 12.56v
Pin 6 - 3.3v

I've replaced the U5400 as a matter of precaution because it originally was presenting at 0.2v which seemed low, however I'm not sure what voltage is supposed to be present at Pin 6? Have spent two weeks on Google but not found any information anywhere!

Also swapped R5400 with R5410 as a matter of testing to see if the fault 'moved' but no difference.

Before I throw this board at the wall, can anyone give me a clue as to what I'm looking for at Pin 6 to get the correct reference voltage for the SMC?

Considering 'white washing' the circuit to see whether that fixes the problem but given that each component tests OK individually with no signs of obvious damage I'm not sure it'll help...

Thanks guys!

 

[2informaticos]

As per schematic:
V across Rsense: 52.2 mV
Rsense: 0.003 (R5400)
Gain: 50x, EDP: 17.4 A

So, for 17A, you will get aprox 2.5V at pin6.
For normal use, must be less.
You get 3.3V, which is extremely high...

0.2V you had before, means aprox 6.5A, more closer to normal.

Possibly bad solders, be sure you have less than 1ohm directly between U5400 pins 4 & 5.

 

[bridportpcrepair]

Thank you for the reply 2informaticos

You've just answered my next question, I had been looking at those values on the schematic and wasn't quite sure how to interpret them!

I'm fairly sure that the soldering isn't an issue, although I'm the first to admit that I'm not an expert, I'll check that tomorrow. I've also got some new U5400 ICs on order.

So if the voltage at pin 6 when it came in originally was around 0.2v (from memory it was something like 0.263v but I've slept since then!) it would have been closer to spec? If so, why would it be throwing the ASD error?

The only other concern that I have is that it may be an SMC issue, although logically the SMC is the output of the circuit so shouldn't be affecting the U5400 surely?

Does anyone have a working board they could take a reference voltage from so that I can have an idea of what sort of range I'm looking for?
​​​​​​
Many questions, I like to understand the bigger picture if possible, sorry!

 

[2informaticos]

There is no fixed voltage; it depends by CPU load...

 

[bridportpcrepair]

Ah OK, fair enough!

I've just discovered (or been told) that the built in ASD stops on the first error, big mistake on my part as I assumed (you know what they say about assumption!) that it would give me a report that was accurate, should know better with Apple really...

Needless to say I'll be downloading and running the EFI ASD tomorrow, obviously this issue now needs fixing too but I reckon there must be something else wrong and I've missed it by assuming that the IC0R error was the only problem... Live and learn...

 

[bridportpcrepair]

OK - so an update!

Having run the proper EFI diagnostics, I've got some more sensor failures...

Sensor - Current (IC0R) - reading above high limit
Sensor - Current (IM0C) - reading above high limit
Sensor - Current (IO0R) - reading above high limit
Sensor - Voltage (VC0C) - reading above high limit
Sensor - Voltage (VC2C) - reading above high limit
Sensor - Voltage (VN0C) - reading above high limit
Sensor - Voltage (VP0R) - reading above high limit

Rather a few more problems!

I haven't been able to poke around the board yet to see what's going on, but is there anything that jumps out as a common fault with this board that might cause all of these sensor failures at once?

Thanks

 

[bridportpcrepair]

Some more information from the EFI test hardware profile:

IO0R - lower limit 0.2A high limit 1.0A, reading 10.996A
IPBR - lower limit 0.1A high limit 1.0A reading 9.165A
ISDC - lower limit 0.0A high limit 0.8A reading 5.078A
VC2C - lower limit 0.6v high limit 1.0v reading 3.298v
VP0R - lower limit 8.75v high limit 14.528v reading 19.763v

and on and on...

So SOMETHING is either pulling the voltages far too high, or I suppose more likely it's not reading the voltages and current correctly.

SMC??

 

[bridportpcrepair]

Been prodding around the board again today.

Had a look at the original IC0R circuit. Removed the U5400, cleaned the pads and resoldered it - now Pin 6 is around 0.18v (better).

However, the ASD still fails on all 7 sensors above, and the values are MILES away from the upper limit. IPBR for example, can it really be 9.165A when the upper limit is 1.0A - surely something would have caught fire?!

Does anyone have any suggestions before I bin this board? I've gently reflowed the SMC - didn't make any difference but I didn't go all out on it as I don't want to knacker it...

 

[dukefawks]

Seems like all analoge inputs to the SMC are reading wrong. Common problem is the AVREF voltage is wrong so ADC converter in SMC will not work right.

Check PP3V3_S5_AVREF_SMC and U5010 area.

 

[bridportpcrepair]

Hi dukefawks

Thank you for the reply. I had reached the same suspicion, was poring over the schematic last night and scouring Google and you'd suggested the same on another post elsewhere. I assumed that the SMC must have a reference voltage to compare to, I just didn't know which one it was.

As soon as I get chance I'll be investigating that circuit! Does sound very likely though...

 

[bridportpcrepair]

Absolutely on the money as always Dukefawks, the cap was shorting to ground on the PP3V3_S5_AVREF_SMC line pulling it down, repaired the tracks, replaced the cap and U5010, then had 3.3v back again where it should be and all is well.

Please mark as solved, and many thanks!