ThinkPad T460s processor frequency i5-6300U

[bykanovm]

Good afternoon. There is Lenovo ThinkPad T460s, NM-A421 rev 3.0 platform with i5-6300U processor. The problem is that the processor runs at a minimum frequency of 0.39 Ghz. Who knows what could be the problem? Faced this on DELL laptops when connecting the wrong charger. Haven't seen this on Lenovo. What is responsible for the CPU clock rate on a ThinkPad?

[mon2]

Re: ThinkPad T460s processor frequency i5-6300U

Yes, can be impacted in the same way..

From the linked wikipedia:

Signal Pin
Power controller subsystem senses when power is connected, and measures resistance between central signal pin and ground. Firmware policy might reduce performance (battery charges slowly, processors throttle to low speed) if an insufficient supply is detected. This issue is discussed at forum.thinkpads.com, "W520 requires 170W AC adapter".

power rating resistance
65 W 10 kΩ
90 W not connected
135 W 0 Ω
170 W 1.5 kΩ

https://www.thinkwiki.org/wiki/Power_Connector

[bykanovm]

Re: ThinkPad T460s processor frequency i5-6300U

Checked the entire ACDC_ID line. All resistor values are correct. Reached the MEC1653 multicontroller. I think it's in him. I'll try to flash different BIOSes, but I doubt that they are the case.

[mon2]

Re: ThinkPad T460s processor frequency i5-6300U

What is the resistance value you measured of this ID pin on the adapter being tested?

Take the measurement without any power to the adapter.

[bykanovm]

Re: ThinkPad T460s processor frequency i5-6300U

The resistance on the bottom contact without the connected adapter is 10 Ком and smoothly increases to 17 Ком. With connected adapter without power supply, resistance 0, short to ground. When applying power, the voltage on this contact is 1.3 V. The resistance of the R258 resistor is 750 Ω, which corresponds to the nominal value in the scheme. The resistor R2090 caused suspicion, its resistance on the board is 75 Ком, although according to the scheme it should be 10 Ком. Changed it to a 10 Ком resistor, nothing changed. The battery is recognized, but when the power supply is turned off, the laptop also turns off immediately, although the battery is fully charged.

[mon2]

Re: ThinkPad T460s processor frequency i5-6300U

Can you post or link the schematic if on this forum?

When you run from the battery only, the logic board is stable and running at the right speed?

[bykanovm]

Re: ThinkPad T460s processor frequency i5-6300U

The laptop does not work from the battery, it immediately turns off when the power supply is turned off. Here is a link to a thread with a diagram.

https://www.badcaps.net/forum/showth...hlight=nm-a421

[mon2]

Re: ThinkPad T460s processor frequency i5-6300U

Is the battery a known good battery?

Remove the battery. Attach only the power adapter.

Meter in dc volts mode (20v or higher).

Red meter probe on ACOK (pin 5) of charger IC (pu101). Black meter probe to ground.

What is the reading?

[bykanovm]

Re: ThinkPad T460s processor frequency i5-6300U

PU101? I don't see that. The voltage is exactly 20V. Served from the laboratory unit and from the power supply, does not stick. Accumulators judging by the consumption of the laboratory unit are not charged. Also, AIDA64 cannot recognize either of the two batteries. The batteries themselves are original.

[bykanovm]

Re: ThinkPad T460s processor frequency i5-6300U

I guess you meant U1

[bykanovm]

Re: ThinkPad T460s processor frequency i5-6300U

On the fifth leg of U1 (BQ24780SRUY) ACOK signal Stable 3.2V

[mon2]

Re: ThinkPad T460s processor frequency i5-6300U

I think we are referencing 2 different schematics. The first link in the shared webpage (Alisaler) has a different schematic than the one in the last post of the same webpage.

Which schematic is matching yours?

[bykanovm]

Re: ThinkPad T460s processor frequency i5-6300U

Last link. It matches my board

[mon2]

Re: ThinkPad T460s processor frequency i5-6300U

Remove the adapter and using the battery only, measure the voltage on each pin of Q8, Q34 and Q13. Post your readings.