Category: Electronics

Electronics technology, controlling electrical energy through circuits and components

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Fixing & Repairing – QNAP NAS TS251+ / TS451+ boot failure

QNAP NAS TS251+ / TS451+ boot failure – LPC clock bug fix

All QNAP NAS devices from the TS-251+ and TS-451+ series appear to be affected by a hardware issue known as the “LPC clock bug,” also referred to as the “Intel clock bug.”

Symptoms:
The NAS powers on but is not accessible over the network, and the LED indicators do not reflect normal operation, as following listed.

Devices with a display show a persistent “System booting…” message, and connected monitors show no video output.

This issue may develop gradually, meaning it can first appear in less obvious ways. For example, one TS-251+ unit occasionally failed to power on at all, or sometimes failed to detect one of the installed RAM modules.

Certain LED patterns also serve as clear indicators of the issue:

    • USB LED remains solid blue
    • HDD1 and HDD2 LEDs remain solid red

These signs strongly suggest the presence of the described hardware fault.

The following seven steps outline the process from identifying the symptoms to resolving the LPC clock bug.

Powered on QNAP NAS TS251+ with boot failure and error LED pattern.
The DC output between LCL and GND is 2.4V, but it should be 1.4V.
Measured at the LCP interface: Pin 1 (LCL) and Pin 8 (GND).
Resistors with a resistance of 100 Ω
Resistor prepared for soldering.
Soldered 100 Ω resistor between Pin 1 (LCL) and Pin 8 (GND) of LCP interface.
LCL and GND now show the correct output of 1.4V. The LED indicator is functioning normally, showing a solid green light.
Measured at the LCP interface: Pin 1 (LCL) and Pin 8 (GND).
The initial boot error on the QNAP NAS has been resolved.
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3D Printing/Modeling and Electronics – Welcome Door Light for Mercedes Benz W211 & C219 Models

Mercedes-Benz W/S211 (E-Class) & W219 (CLS)
3D-Printed Welcome Door Light Bracket with Custom Electronic PCB

Having trouble finding a compatible shadow light (also known as door light or welcome light) for the Mercedes-Benz W/S211 (E-Class) or W219 (CLS)?
You’re not alone—there’s virtually nothing available online or in stores.

But here’s the good news: it’s entirely possible to 3D print and assemble your own custom shadow light bracket, designed to fit plug-and-play into the existing festoon (Soffitten) bulb socket—no modifications needed.

Required Components for the Custom Shadow Light

    • Ball head screws (Tamiya Ball Connector 5mm, SP-592)
    • 0.055 mm² wires in various colors
    • CAN bus-compatible LED driver module
    • LED projector with your desired logo
    • V2A micro countersunk screws (1.2 × 6 mm)
    • Soldering iron and a bit of skilled craftsmanship

🔧 The STL files for 3D printing the bracket are available for download on Thingiverse.

Initial Situation

The following festoon bulb (Soffitte) and cover are factory-installed in the door bracket of the Mercedes-Benz W/S211 (E-Class) and W219 (CLS).

The 3D models

    • Bracket
    • Lid

Assembled 3D Print with CAN Bus Module and LED Logo Projector

The Final Result

Electronic Module – Circuit Board (PCB)

This custom circuit board is built around a central PT4115 step-down LED driver, which regulates power using an inductor (coil). This design ensures that energy is efficiently managed and not dissipated as heat.

A Glass Passivated Bridge Rectifier (MB10F) is integrated to provide reverse polarity protection, allowing the Shadow Light to function correctly even if installed with reversed wiring.

Ressources

3D plan and construction:  AutoDesk Fusion 360
3D printer: Anycubic Mega S
Filament: Form Futura TitanX ABS