The LA-E801P Rev 2.0 schematic is a critical resource for technicians repairing HP 15-BS series laptops. While the Rev 1.0 version is more widely available online, finding the specific Rev 2.0 diagram is essential for troubleshooting newer iterations of this motherboard that may feature updated power rails or component layouts. Core Technical Specifications LA-E801P motherboard
(also known by its CSL50/CSL52 design codes) typically features the following hardware:
Processor: Supports Intel Sky Lake-U or Kaby Lake-U processors (BGA 1356P). Memory: Dual DDR4 SODIMM slots.
Graphics: Options for UMA (Integrated) or discrete GPU (AMD R17M-M1/M2) with dedicated DDR3L VRAM.
Power System: Managed by a complex sequence of VRM controllers, including dedicated regulators for +3VLP, +5VALW, and +3VALW. Common Issues & Troubleshooting Steps
Technicians frequently use the LA-E801P Rev 2.0 schematic to resolve several recurring motherboard faults: "Dead" or No Power Faults:
Voltage Checks: Verify if 19V is passing through the first and second MOSFETs (e.g., PQA1).
Standby Rails: Ensure the 3.3V and 5V standby voltages are present. A common failure point on this board is the source side of the power-in MOSFETs showing unusually low resistance (e.g., 7Ω), which often indicates a short circuit in the downstream rail. No Display Issues:
BIOS Corruption: Many "No Display" cases on the LA-E801P are resolved by flashing a fresh, tested BIOS binary.
RTC Section: Problems in the Real-Time Clock (RTC) circuit can prevent the board from completing its power-on sequence. Graphic Conversion (UMA Enable):
For boards with failing discrete AMD GPUs, the Rev 2.0 schematic provides the necessary jumper and resistor configurations to disable the dedicated chip and force the system to use integrated Intel graphics. Why Revision 2.0 Matters
Repairing a Rev 2.0 board using a Rev 1.0 schematic can be misleading. Manufacturers often tweak the power-on sequence or swap out proprietary PWM controllers between revisions. The Rev 2.0 diagram ensures you are measuring the correct test points and referencing the exact part numbers for surface-mount components.
Title: The Ghost in the Gain Topic: LAE801P Rev 20 Schematic Better lae801p rev 20 schematic better
The rain in Seattle hammered against the corrugated metal roof of the warehouse, a rhythmic drumming that usually soothed Elias. Tonight, however, it just grated on his nerves. He sat hunched over a workbench cluttered with oscilloscope probes and half-empty coffee mugs, staring at the crown jewel of his current headache: the LAE801P industrial servo controller.
It was a beast of a machine, responsible for the precision articulation of automated assembly arms in the aerospace sector. The client, Aerodyne Systems, was losing millions every hour their production line sat idle. The problem was maddeningly intermittent. The controller would run for six hours, then fault out with an "Over-voltage" error that made no sense given the load.
Elias rubbed his eyes. He had been tracing the board for days. He was looking at the schematics for Revision 19. It was a mess—a digital collage of redlines, white-out, and PDF layers that had been scanned and re-scanned until the component values looked like blurry Rorschach tests.
"Parasitics," Elias muttered to himself. "It has to be parasitic inductance on the gate drive."
He was about to desolder the MOSFET array for the third time when his email pinged. It was a message from the older, reclusive engineer who had designed the original platform, a man named Arthur Vance. The subject line was simple:
Use this. Rev 20 is better.
Elias opened the attachment. It was labeled LAE801P_Rev20_Schematic_Better.pdf.
He almost laughed. "Better? What is this, a software patch note?"
But as the vector lines rendered on his high-resolution monitor, the laughter died in his throat. The difference wasn't just cosmetic; it was foundational.
The Revision 19 schematic Elias had been working from was functional, but it was a victim of "digital clutter." The grounding paths were ambiguous, drawn in a way that suggested the layout engineer had struggled to fit the traces onto the board. The signal lines for the current sensing op-amps ran parallel to the high-voltage switching lines—a classic recipe for noise injection. In the PDF, the lines were drawn on top of each other, obscuring the interference.
Revision 20, however, was a revelation.
Elias zoomed in on the power stage. In the older drawing, the bootstrap capacitor for the high-side driver was connected via a long, winding trace symbolized by a generic line. In the new "Better" schematic, the drawing was restructured to emphasize the physical layout. The LA-E801P Rev 2
"Star grounding," Elias whispered, realizing the error of his previous analysis. "They moved the return path."
The Revision 20 schematic didn't just show the components; it visualized the physics. It clearly delineated the "noisy ground" (the power ground) from the "quiet ground" (the signal logic ground), showing exactly where they met—at a single point near the supply inlet.
Elias traced the signal path with his cursor. The previous revision had the feedback loop for the voltage sensor routed right past the switching node. It was a noise antenna. Rev 20 showed a "Kelvin connection"—a dedicated pair of traces for sensing that bypassed the high-current path entirely.
The schematic was drawn with a clarity that bordered on art. The nets were colored to indicate voltage levels. The bypass capacitors were placed not just symbolically, but in positions that indicated physical proximity to the IC pins.
"It's not just a drawing," Elias realized, his heart beating a little faster. "It’s a map of where the electrons want to go."
He looked back at the faulty board on his desk. He had been looking for a bad component. He had replaced chips, capacitors, and resistors. But the ghost in the machine wasn't a bad part; it was a bad layout, exacerbated by a confusing schematic that had misled every technician who looked at it.
The Rev 20 schematic revealed that the gate resistor—R422—was critical. In the blurry scan of Rev 19, it looked like a 10-ohm resistor. But in the crisp, high-contrast lines of Rev 20, the value was clearly updated. It wasn't 10 ohms
The Compal LA-E801P Rev 2.0 is a motherboard used in HP 15-BS series laptops and the HP 250 G6. While Rev 1.0 schematics are common, Rev 2.0 is often sought for its specific power rail and component layout updates. Schematic & Boardview Resources
You can find documentation for this board through several technical repositories and repair forums:
Detailed Schematic & BIOS: IndiaFix provides files specifically labeled for Rev 2.0, which can be essential for identifying differences in power management or discrete GPU configurations.
Boardview Files: For physical component location, LaptopServiz offers boardview files that assist in tracing signal paths on the PCB.
Technical Discussions: If you are troubleshooting power issues (like "no lights"), the Elvikom Forum has active threads where technicians share specific voltage measurements and component identifications for this exact revision. Technical Specifications (CSL50/CSL52) The LA-E801P board typically features: Platform: Intel Sky Lake-U or Kaby Lake-U (7th Gen). The Revision 19 schematic Elias had been working
Graphics: Integrated UMA or Discrete AMD Radeon (R17M-M1-30). Memory: Dual DDR4 SODIMM slots.
Common Component: Uses the PE642DT dual transistor for critical power switching.
Are you troubleshooting a specific power rail or looking for a component identification (like a burnt IC)?
HP-15t-bs000 (MOBO. LA-E801P REV. 2.0) Not Working - No Lights
Beyond pure electronics, Rev 20 is better for a logistical reason: it uses standard, available parts. Earlier revisions relied on a specific, hard-to-find 1.2µH inductor (L3) from a discontinued line. Rev 20’s schematic calls out three alternative inductors (Murata, Bourns, Wurth) with identical footprints and electrical characteristics.
In an era of supply chain chaos, a schematic that is component-agnostic while maintaining performance is not just better—it is survival-oriented. Rev 20 acknowledges that the best design is the one you can actually build.
| Parameter | Original Rev 20 | Improved Rev 20B | |-----------|----------------|------------------| | Output ripple (20MHz BW) | 210mV pk-pk | 38mV pk-pk | | Switching node overshoot | 28V | 16V | | Max load before thermal shutdown | 3.2A | 5.1A | | EMI (CISPR 22, 30-100MHz) | Fail | Pass with 6dB margin | | Efficiency at 4A | 81% | 89% |
The current limit resistor (Rcl) has been repositioned from the high side to the low side, sharing the reference ground plane. This eliminates common-mode voltage errors, improving current limit tolerance from ±15% to ±5%.
Even with a better schematic, layout kills performance. For Rev 20 boards:
Original compensation (Type II) caused phase dip at crossover.
Improved Type III compensation:
Result: Phase margin increases from 28° → 62°.