TCS Pune

820-01700 – Bench Power & Signal Checklist

Board-specific bench checklist derived from 1 supplied source PDF(s). Source coverage: High. Verify exact thresholds, pin numbers and rail tolerances against the source schematic and component datasheets before component replacement or voltage injection.

🔌 820-01700Expert⏱ 60-180 minutes📋 5 steps

Compatible models: A2141 X970

⚠ Safety: Disconnect battery before resistance/diode checks. Use current limiting for injection. Never inject voltage into an unknown rail until its safe voltage/current limit and isolation path are confirmed. Use a short ground spring for high-speed oscilloscope probing.

🛠 Required Tools

Digital multimeter Oscilloscope with x10 probe Bench power supply with current limit Thermal camera / freeze spray as required SPI programmer where firmware diagnosis is required

0 / 5 done

1Confirm board identity and fault conditionRecord exact board code/revision, reported symptom, adapter/battery condition, and whether the board is in G3/S5/S0 or cycling.⚠ Use the exact board revision; similar board codes can use different power ICs.
2Unpowered resistance / short checkWith all power removed, check main input, always-on rails, memory rails and CPU/GPU rails for abnormal resistance to ground. Compare with known-good behavior when available.⚠ Low resistance on CPU/GPU core rails can be normal. Do not inject voltage until the rail topology and safe limit are confirmed.
3Trace the chronological power sequenceUse Table A in order. Stop at the first missing prerequisite, then diagnose upstream rather than replacing downstream components.⚠ A missing downstream signal is often a consequence, not the root cause.
4Capture dynamic signals with oscilloscopeUse a x10 probe and short ground connection. Capture power-button, sleep-state, reset, SPI, PWM and bus activity under the actual failure condition.⚠ Avoid long probe ground leads on switching nodes and high-speed buses.
5Record repair and verify all functionsAfter repair, repeat the failed stage, complete the sequence, test charging, battery, display, ports, thermal behavior, sleep/wake and multiple cold boots.⚠ Do not mark solved until the original symptom is reproducibly cleared.

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Schematic-derived bench record

Bench Manual & Source Coverage

Source coverage: High. Values and thresholds must still be verified against the exact schematic/datasheet.

Source PDF(s): A2141 820-01700 X970.pdf | A2141_820-01700 Large inductance resistance.pdf | 820-01700-05 High definition scan.pdf

Board profile

Power & Control Architecture

CPU / SoCSkylake

MemoryDDR4

ChargerRAA225101A2

USB-C / PDCD3217

Table A

Chronological Power Sequence

Follow upstream to downstream. A missing later signal may simply be the result of an earlier missing prerequisite.

#	Stage	Signal / Rail	From -> To	Ref	State	Expected	DMM	Oscilloscope
1	DC Input	Adapter / DC-IN main rail	Adapter/battery input path	Schematic p.1	Follow chronological sequence	19-20 V typical for barrel adapters; USB-C depends on PD contract	Measure to ground at input connector/fuse	Flat DC; inspect ripple only if unstable
2	Battery	Battery positive / system battery rail	Battery connector -> charger/system	Schematic p.49	Follow chronological sequence	Pack voltage appropriate to cell count and state of charge	DMM DC at battery positive to pack ground	Flat DC; no excessive ripple
3	Battery	Battery SMBus clock	EC/charger battery	Schematic p.15	Follow chronological sequence	Pulled high with communication activity when battery is queried	DMM shows logic-high average; scope preferred	Digital clock bursts
4	Battery	Battery SMBus data	EC/charger battery	Schematic p.15	Follow chronological sequence	Pulled high with bidirectional data activity	DMM shows logic-high average; scope preferred	Bidirectional data bursts
5	RTC	RTC / CMOS supply	RTC source -> PCH/SoC	Schematic p.16	Follow chronological sequence	Typically near 3 V; board-specific	DMM DC	Flat DC
6	EC / SIO	32.768 kHz RTC / EC clock	Crystal/oscillator -> EC/PCH	Schematic p.77	Follow chronological sequence	Stable 32.768 kHz where external low-frequency clock is used	DMM not reliable; use scope	Stable low-amplitude sine/square waveform near 32.768 kHz
7	Power State	RSMRST#	EC/PCH resume-well logic	Schematic p.12	Follow chronological sequence	Inactive/high after resume-well prerequisites are satisfied	DMM logic level	Clean low-to-high transition during standby initialization
8	Power Sequence	SUS_ON / MAINON	EC/power logic -> main regulators	Schematic p.78	Follow chronological sequence	Active state enables main/S0 rails; polarity board-specific	DMM logic level	Clean enable transition
9	Memory	DDR VDD / VDDQ	Memory regulator -> DIMM/SoC	Schematic p.8	Follow chronological sequence	DDR generation-specific rail; verify schematic and memory generation	DMM DC at memory inductor	Flat DC; low ripple
10	CPU / SoC	VCCIO / CPU I/O rail	VR -> CPU/SoC	Schematic p.1	Follow chronological sequence	Platform-specific, commonly around 0.8-1.05 V on Intel generations	DMM DC at inductor	Flat DC; switching only at PWM nodes
11	CPU / SoC	VCCSA / System Agent	VR -> CPU/SoC	Schematic p.8	Follow chronological sequence	Platform-specific, commonly around 0.8-1.1 V	DMM DC at inductor	Flat DC
12	CPU / SoC	VR_ON / CPU VR enable	EC/PCH -> CPU VR controller	Schematic p.69	Follow chronological sequence	Active before CPU core rail starts; logic level is board-specific	DMM logic level	Clean enable edge
13	CPU / SoC	CPU core rail	CPU VR -> processor core	Schematic p.10	Follow chronological sequence	VID-controlled dynamic voltage; do not use a single universal value	DMM DC at core inductor	Multiphase switching on switch nodes; DC on output
14	CPU / SoC	VR power-good	CPU VR -> EC/PCH	Schematic p.69	Follow chronological sequence	Asserted after CPU VR outputs are valid	DMM logic level	Clean assertion after core rail rises
15	Power Good	SYS_PWROK / ALL_SYS_PWRGD	PGOOD logic -> PCH/SoC	Schematic p.12	Follow chronological sequence	Asserted only after required S0 rails are valid	DMM logic level	Clean delayed assertion
16	Power Good	PCH_PWROK / SoC power-good	EC/PGOOD logic -> PCH/SoC	Schematic p.12	Follow chronological sequence	Asserted when platform power prerequisites are valid	DMM logic level	Clean delayed assertion
17	BIOS / SPI	SPI_CLK	PCH/SoC/EC -> SPI flash	Schematic p.12	Follow chronological sequence	Clock bursts during firmware access	DMM not diagnostic; use scope	High-frequency clock bursts
18	Display	eDP / LCD panel power	Load switch -> panel connector	Schematic p.15	Follow chronological sequence	Usually 3.3 V or platform-specific panel logic rail	DMM DC at panel connector/fuse	Flat DC
19	Display	eDP HPD	Panel -> GPU/PCH/SoC	Schematic p.15	Follow chronological sequence	Valid HPD logic state when panel is connected and powered	DMM logic level	Clean logic level/transition
20	Display	Backlight enable	EC/PCH/GPU -> panel/backlight	Schematic p.15	Follow chronological sequence	Active logic level when backlight should turn on	DMM logic level	Clean assertion after panel power
21	Display	Backlight PWM	EC/PCH/GPU -> backlight driver	Schematic p.38	Follow chronological sequence	PWM duty cycle controls brightness; amplitude board-specific	DMM may show averaged voltage; scope preferred	PWM waveform with variable duty cycle
22	USB-C / PD	USB-C VBUS	USB-C port -> system power path	Schematic p.30	Follow chronological sequence	5 V default; 9/15/20 V or other profiles after valid PD contract	DMM DC	Flat negotiated DC; scope for transients only

Table B

Bench Reading & Fault Isolation

Enter the actual DMM reading and scope/logic observation. Select PASS, FAIL or N/A, then tick Checked when that row is complete.

0 / 22 checked

Checked	#	Signal / Rail	Failure Isolation Hint	Technician Notes
Checked	1	Adapter / DC-IN main railSchematic p.1	No rail: inspect adapter, jack, fuse, protection MOSFETs Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	2	Battery positive / system battery railSchematic p.49	Abnormal: verify pack, connector, BATFET and charger path Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	3	Battery SMBus clockSchematic p.15	No activity: check pull-up rail, EC/charger, battery presence and bus shorts Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	4	Battery SMBus dataSchematic p.15	Stuck low/high: isolate battery/device and pull-up path Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	5	RTC / CMOS supplySchematic p.16	Missing RTC can block RSMRST# and standby sequencing Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	6	32.768 kHz RTC / EC clockSchematic p.77	No clock: inspect crystal, load capacitors, supply and oscillator pins Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	7	RSMRST#Schematic p.12	Held low: trace RTC/standby rails, EC firmware, PCH/SoC prerequisites Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	8	SUS_ON / MAINONSchematic p.78	Missing: identify prior PGOOD/sleep signal that inhibits EC output Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	9	DDR VDD / VDDQSchematic p.8	Missing: check enable from S4/S3 logic and resistance to ground Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	10	VCCIO / CPU I/O railSchematic p.1	Missing: check enable, short and regulator controller Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	11	VCCSA / System AgentSchematic p.8	Missing: check enable/PGOOD and CPU rail sequencing Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	12	VR_ON / CPU VR enableSchematic p.69	Missing: EC/PCH has stopped sequence; inspect previous power-good signals Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	13	CPU core railSchematic p.10	0 V: verify VR_ON, controller supply, phase short and CPU condition Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	14	VR power-goodSchematic p.69	Missing: inspect VR feedback, phase faults, overcurrent/thermal protection Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	15	SYS_PWROK / ALL_SYS_PWRGDSchematic p.12	Missing: identify which upstream PGOOD/rail is absent Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	16	PCH_PWROK / SoC power-goodSchematic p.12	Missing: trace aggregate power-good logic and required rails Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	17	SPI_CLKSchematic p.12	CS toggles but no clock: inspect controller/bus; no bus activity: trace sequence first Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	18	eDP / LCD panel powerSchematic p.15	Missing: check panel power enable, fuse/load switch and shorted panel/cable Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	19	eDP HPDSchematic p.15	Missing: panel/cable/connector power or HPD trace issue Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	20	Backlight enableSchematic p.15	Missing: lid/Hall state, graphics sequence, panel detection or firmware Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	21	Backlight PWMSchematic p.38	Enable present but no PWM: brightness/graphics/EC control path issue Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence
Checked	22	USB-C VBUSSchematic p.30	Stuck at 5 V/no VBUS: inspect CC negotiation, PD controller and power-path FETs Additional readings Resistance to ground (Ω)Diode mode (V)Current consumption	Technician evidence

V4.0 · BOARD COMPONENT INTELLIGENCE

Component Index

Select a board component to see its function, related rails/signals, enable and power-good dependencies, input/output path, matching checklist tests and identical fitted ICs found on other board checklists. Unknown values are left unknown rather than guessed.

V4.3 Bench PSU Current Profile

Board Current Sequence

Record current draw in amperes at each observable stage. Historical comparison uses successful repairs of this exact board checklist. A different reading is a clue, not a component diagnosis.

Current sequence: No readings yet

Adapter connectedANo successful-repair baseline yet

StandbyANo successful-repair baseline yet

Power-button pressANo successful-repair baseline yet

CPU initializationANo successful-repair baseline yet

BIOS activityANo successful-repair baseline yet

POSTANo successful-repair baseline yet

Tip: enter only stages you actually observed. For boards that never reach a later stage, leave that stage blank rather than entering a guessed value.

V4.4 Board Knowledge

Previous Solved Cases

Historical cases are diagnostic references only. Confirm readings on the board in front of you before replacing parts.

Live match: Mark a bench signal FAIL to check previous solved cases for 820-01700.