Resistor value identification

[hopkok]

Hi guys, what is the resistor value of R7201? Not sure.

Thank you

[hopkok]

Can it be 1,78Mohms?

[mon2]

No. The '1' is a bad cad to pdf conversion sideband issue.

Which exact model are you reviewing? Which motherboard? The shared screen does not display the required details.

[hopkok]

Hi mon2, LENOVO Thinkpad P1 Gen2 - Wistron 18809-1, schematic attached. R7201 position, marked as "1D78MR2F-GP".

Thank you

[mon2]

Page #2 has a resistor part decoding scheme posted. Suggest to hunt for other schematics with the Think Engine part to compare this value. Will review later.

[reformatt]

Nice find. Never noticed that before, thought it was a manufacturer part number or something. So the D probably stands for decimal. So....

1.78Meg 0402 1% tolerance

[hopkok]

I decoded it for 1,78Mohms too...

[mon2]

Remove all power. Meter in resistance mode. Measure the resistance across the low side of this circuit. What is the exact resistance in ohms?

Use a resistor based voltage divider calculator (Digikey is ok) and stuff in the values you believe should be on the high side and the low side with 20V as the power rail.

What is the voltage that should be seen by the Think Engine chip? This voltage must be at a safe value else the voltage will kill the think engine controller. Post your measurements.

From another Lenovo schematic with the think engine component: