Help Request for Lenovo L470 - No power

[nikal]

The voltage on CMSRC pin # 3 cannot be at 0v for the charger to function. It must have the adapter voltage as in a normal power path flow onto the main rail. Absent voltage here will make the charger IC believe the adapter voltage is missing.

Thanks again for your reply,

Well....The reason for this was that I injected power after the second MOSFET whereas in order for the pin3 to have power I should have injected power after the first mosfet (based on the schematic). I did it and I checked pin3 which had 12,5V (there is a resistor between the main power rail and the Pin3 so there is a drop there). However, the gates of the MOSFET where at 0V again.

Then I checked again the schematic (attached) and I decided to remove PQ44 which is controlled by the Pin98 of EC which I think turns the input FETs OFF by shorting ACDRV to ground et voila! The laptop now can be powered by the DC-IN input meaning that the dcin FET are now open and I can see the 10mA current consumption in my bench power supply which is the EC power when the system is OFF.

What do you think about it ? Was the PQ44 faulty, or the EC pulled the ACDRV to the ground for some reason ? Please note that the EC is transferred to this laptop from another board and it apparently must be programmed with the specific firmware in order to work as it should.

Any ideas and suggestion are welcome.

Thanks in advance for help and time.

[nikal]

Just to clarify, the laptop won't turn on but I can measure all the standby voltages (including 1V for the PCH I think and 8.5V in the battery coil). When I put the adapter I see again around 185mA current draw which immediately drops to 10mA.

[nikal]

Correction for the above. The current immediately drops to 1mA.

[mon2]

Remove all power. Meter in resistance. Measure the resistance between pins 1 & 2.

[nikal]

Remove all power. Meter in resistance. Measure the resistance between pins 1 & 2.

hi again!

21.3 Ohms agrees with the values on the schematic.

[mon2]

Confirm the voltage to ground on pin 28 (Vcc) of PU7. Is it stable?

[nikal]

Confirm the voltage to ground on pin 28 (Vcc) of PU7. Is it stable?

19.30V and I don't see any fluctuation.

[nikal]

Just an update, I replaced Q44 and I'm not sure if this is relevant or not (I can't see the connection) but now I have battery charging but the system won't power on still. It's probably because it's the first time I left the battery connected for a considerable lengthy time since it apparently was very discharged.

However this shows that the EC somehow communicates through SMBUS with the BQ and battery and enables charging. But still won't power on the system. Is it an EC firmware issue or what ?

EDIT
What I noticed is that it takes some time to enable the charging. It's not a matter of a few seconds but a couple of minutes.

[mon2]

SMBUS consists of SMBUS slave nodes and usually a single SMBUS bus master that initiates or drives the clock signals. This interface will ping a node with an address and if the address matches, then the addressed slave will respond. The BQ chip is one example of a SMBUS slave.

The EC is the SMBUS master so it will be the device that initiates and programs the BQ SMBUS slave for configuration or other actions. Respectively, the EC must use firmware for this action. Not an EC person but the EC firmware may be embedded or could be external that is loaded through an external local SPI flash device.

PQ44 is used to turn off the ACDRV voltage to shunt the DCin power path from the power adapter. If PQ44 is turned ON, the ACDRV voltage is suppressed. ACDRV needs to be a higher or boosted voltage to enable the DCin N-channel mosfets and often ~25 volts.

[nikal]

SMBUS consists of SMBUS slave nodes and usually a single SMBUS bus master that initiates or drives the clock signals. This interface will ping a node with an address and if the address matches, then the addressed slave will respond. The BQ chip is one example of a SMBUS slave.

The EC is the SMBUS master so it will be the device that initiates and programs the BQ SMBUS slave for configuration or other actions. Respectively, the EC must use firmware for this action. Not an EC person but the EC firmware may be embedded or could be external that is loaded through an external local SPI flash device.

PQ44 is used to turn off the ACDRV voltage to shunt the DCin power path from the power adapter. If PQ44 is turned ON, the ACDRV voltage is suppressed. ACDRV needs to be a higher or boosted voltage to enable the DCin N-channel mosfets and often ~25 volts.

Hi again and thanks for the reply,

Yes I know the SMBUS. Apparently the EC has a firmware (loaded from the other board that I removed it which was not the same as the board it is now) and has some charging parameters preprogrammed and uses these for charging. The BQ24780 has a specific address in the SMBUS (b00010010 (0x12H)) and this EC was removed from a board that used the same BQ IC so it can initiate the communication. But apart from this, I believe now I reached a dead end. Either I have to attempt and program the EC with the correct firmware for this board (which I don't know how I can find) or trash it as non repairable.

BTW, the DC-IN FETs were ON without the PQ44 in place which means that the default state of this FET is OFF and it was apparently faulty, that's why I had the problem with the DC-IN FETs in the first place. Now all the standby voltages and the charging work but the system won't power on.

Do you by any chance have any suggestion on how to program the EC ? I mean, what programmer should I use? SVOD is crazy expensive and RT809F has some limitations. Is there any other solution somewhere in the middle of these two? And what about the EC firmware (I wasn't able to find something for this specific board) ? Can I extract it from the BIOS dump and how?

Thanks in advance for your help and time.

[mon2]

Which EC is onboard? Have you checked Aliexpress? Recently returned from travels to HK & Shenzhen. Shenzhen is flooded with electronic stores and if it is not available there then it does not exist. Hundreds upon hundreds of stores with computer and electronic parts (new & refurbs). This was on just one floor where I was lost hunting for Master Liu of the YT fame. Apparently he was on floor # 3 and I went through only floors 1, 2 and 4. Next time will visit his store.

Yes SVOD is expensive but you have to respect the effort the developers have placed on creating such a tool. Often the details of the EC are not public so they have to reverse engineer the entire process and this is very time consuming. It is also very possible that the EC is side loaded through the PCH or similar upon each power up OR is incorporated by the BIOS reflashing process.

Post the full part # of the EC on your logic board.

[nikal]

The EC is Lenovo branded but it has the code "IT8586E/AX 128L" So you are telling me to buy a preprogrammed one, right ? And a trip to HK or Shenzhen is out of question too (though I would be very glad to meet Master Liu in person 😄)

Yes I know about SVOD and reverse engineering efforts but it won't pay back its money at least for me. It's an investment I can't do right now.

It would be very interesting though if I could force somehow side loading of the firmware.

[mon2]

Shenzhen was a crazy experience for this travel. I did not announce my visit to his shop and eventually chatted with him upon my return. I have his full contact details now. He has another location as well. The locals hardly speak a word of english so had rough details on where he could be found. Totally impressed by the depth of electronics at the building in Shenzhen where they are concentrated. Will post a few pics later.

See attached. Appears that you should have a local rom onboard for the firmware?

This is from a different schematic found on the internet.

[nikal]

mon2

Here is the same part from the L470 schematic. If this is correct it seems there is indeed an external SPI flash holding the firmware but I think it's a reference to BIOS SPI.

(Waiting the pics from your trip, just sent me a PM)

[mon2]

From the Lenovo website:

https://support.lenovo.com/ca/en/dow...-thinkpad-l470

[nikal]

From the Lenovo website:

https://support.lenovo.com/ca/en/dow...-thinkpad-l470

Yes I know that however, if there is already a firmware in the internal flash of the EC the PCH won't try to force a new EC firmware flashing (or is it the EC its self that triggers the flash procedure?) So the only way is the external flashing using a programmer. It's unfortunately a dead end as I said. System won't power up without the correct EC firmware so there is no way to initiate a EC firmware flashing. That's my assumption. In the meantime, I found the EC firmware in Vinafix but this is a paid site and in addition, I need to buy a programmer too. What about Vertyanov in case I decide to buy one?

[mon2]

There at least a few techs who own these programmers so wait for their feedback. We purchased the higher end T56 unit but have yet to come across the need to reflash the EC and would likely need some adapter to mate with the keyboard connector.

[nikal]

There at least a few techs who own these programmers so wait for their feedback. We purchased the higher end T56 unit but have yet to come across the need to reflash the EC and would likely need some adapter to mate with the keyboard connector.

Hi,

if it happens to use it please post some comments. I may also consider SVOD4, it costs around €230 including different flex cables and expansion board for EC programming which initially I thought I had to buy separately, but they are finally bundled.

[mcplslg123]

Programming ITE8586E with correct firmware is a must for mb to post. The EC firmware should'nt be an issue.It can be extracted from lenovo bios update by likes of SMDFlea and other bios masters. You need to get an ec programmer though.
SVOD4 is the best in business.However, this ITE can be programmed with RT8209H via SMBUS interface also.

[nikal]

Programming ITE8586E with correct firmware is a must for mb to post. The EC firmware should'nt be an issue.It can be extracted from lenovo bios update by likes of SMDFlea and other bios masters. You need to get an ec programmer though.
SVOD4 is the best in business.However, this ITE can be programmed with RT8209H via SMBUS interface also.

Thanks for the reply and info.

I have removed this ITE from a Lenovo AMD motherboard and transferred to a Lenovo Intel m/b. It's a "miracle" that it even charges the battery somehow (with fixed current, though). The m/b doesn't power on but I'm sure the culprit is the wrong EC firmware loaded to the EC. Despite that I see all the standby voltages present which means that the original issue (burned 3.3 ALW/LDO power supply and burned EC) is fixed.

Do you have any link that shows RT8209H/F programming ITE through SMBUS ? I thought this was done using SPI or ISP.

Kind Regards