Elitebook 840 G5 CPU Stuck on 0.40 GHz

[medinfo]

HP Elitebook 840 G5, CPU Stuck on 0.40 GHz, this problem can be fixed by (ThrottleStop) by disabling (BD PROCHOT), but i need to fix this problem.

-Charger original, same voltage and watts
-Battery original good health
-Windows Clean install
-Changed all parts, ssd, ram ....

[mon2]

Perhaps same voltage and watts but it is the adapter ID analog voltage (HP models only) that is read by the EC that matters and defines what the logic board will support. If the ID voltage is too low, the cpu will throttle and halt charging etc. Review the center pin voltage of this adapter at the dcin connector contact. Compare this voltage to other working HP laptops.

This safe and lower voltage is sampled by the A/D converter in the EC to gauge the power of the adapter. There are public articles on this topic.

[medinfo]

Perhaps same voltage and watts but it is the adapter ID analog voltage (HP models only) that is read by the EC that matters and defines what the logic board will support. If the ID voltage is too low, the cpu will throttle and halt charging etc. Review the center pin voltage of this adapter at the dcin connector contact. Compare this voltage to other working HP laptops.

This safe and lower voltage is sampled by the A/D converter in the EC to gauge the power of the adapter. There are public articles on this topic.

i know this errors from the charger, but i tested with others chargers, type c charger same problem

[medinfo]

Perhaps same voltage and watts but it is the adapter ID analog voltage (HP models only) that is read by the EC that matters and defines what the logic board will support. If the ID voltage is too low, the cpu will throttle and halt charging etc. Review the center pin voltage of this adapter at the dcin connector contact. Compare this voltage to other working HP laptops.

This safe and lower voltage is sampled by the A/D converter in the EC to gauge the power of the adapter. There are public articles on this topic.

and same problem without charger only battery

[mon2]

If you use Type C power adapter -> what is the voltage and current draw showing on the type C meter? Is the cable between the adapter and this laptop supplied with the power adapter (captive cable and is not removable) or did you attach this extra type C cabling? The details of the type C cable is important. For proper support, the type C cable should be an active cable and rated for 100W (or higher). Only then will you have the E-marker chip inside the cable head and the gauge of the wires inside the cable will be beefy enough to support higher currents. If the cable is NOT e-marked, then you will throttle even the type C adapter and this will throttle the logic board speed and features.

BTW - Can you link or post a schematic? Only inside the schematic forum. My (paid sub) database does not appear to offer this schematic.

[medinfo]

i tested with a lots of original charger, 65w type-c cable not removal, hp blue with same voltage and amp, and without charger only battery powerd same problem

[mon2]

Any schematics?

Locate the charger IC. Is it the BQ24780S?

[medinfo]

Any schematics?

Locate the charger IC. Is it the BQ24780S?

Charger iC Schematic

From @abdoelhosseiny@aol.

[mon2]

Measure the voltage to ground of pin # 23 on this charger IC.

[medinfo]

Measure the voltage to ground of pin # 23 on this charger IC.

3.97V

[mon2]

So this throttle action is NOT from this charger IC. When does this board 'slow down'? Is it after the logic board is mounted inside of an enclosure? There is a thread on this forum where there was a shorting during the clamshell assembly and this led to the logic board being throttled.

[medinfo]

both, motherboard mounted or unmounted, but i noticed an abnormal overheat in the ec controller (NUVOTON) when charger or battery is connected.

[mon2]

Study the adapter ID pin which should be a safe voltage created by resistor based voltage dividers. What is the voltage on this pin when the adapter is connected? If it is too high, this could be an issue. This voltage is sampled by an A/D converter on the EC to determine the power adapter rating.

[medinfo]

Study the adapter ID pin which should be a safe voltage created by resistor based voltage dividers. What is the voltage on this pin when the adapter is connected? If it is too high, this could be an issue. This voltage is sampled by an A/D converter on the EC to determine the power adapter rating.

the voltage in the charger before it's 19.80/10v, and after connected 19.77/0.463v

[medinfo]

any idea ?

[mon2]

At this time, the CPU is being throttled. What is the voltage to ground of PROCHOT#? This is pin #23 of the charger IC you have linked earlier. This label is with a '#' suffix which means the logic line is active LOW. That is, only if this signal is LOW = ~0 volts then the CPU will be throttled due to this signal.

The fault may be elsewhere since this signal is ~3v97 = logic high.

Does the ThrottleStop software work for you? When you run this software, what is the voltage to ground of PROCHOT#?