## Product Title
**StoneTaskin High Quality For Lenovo ThinkPad X1 Carbon 10th Gen Motherboard – 5B21K90412 5B21J13732 – i5-1245U 16GB – Fully Tested – Free Shipping**
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## Short Description
> Genuine replacement motherboard for Lenovo ThinkPad X1 Carbon 10th Gen. Model numbers 5B21K90412 / 5B21J13732. Intel Core i5-1245U. 16GB RAM soldered. Fully tested. Free shipping. 45-day warranty.
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## Key Features (Bullet Points)
- ✅ **Designed for ThinkPad X1 Carbon 10th Gen** – Exact fit for Lenovo ThinkPad X1 Carbon Gen 10 laptop.
- ✅ **Intel Core i5-1245U Processor** – 12th Gen, 10 cores, 12 threads. Powerful performance for business and productivity.
- ✅ **16GB RAM Soldered Onboard** – LPDDR5 memory. Ready to use, no extra RAM purchase needed.
- ✅ **Compatible Part Numbers** – Replaces 5B21K90412 and 5B21J13732. Direct match for easy repair.
- ✅ **100% Fully Tested** – Every board undergoes power-on, display, keyboard, port, and memory testing before shipping.
- ✅ **Free Shipping** – No extra cost. Fast and tracked shipping included.
- ✅ **45-Day Warranty** – Buy with confidence. 45-day coverage against defects.
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## Product Description
**Original Quality Replacement for Lenovo ThinkPad X1 Carbon 10th Gen**
Is your ThinkPad X1 Carbon Gen 10 experiencing no power, no display, random freezes, or liquid damage? The StoeTaskin 5B21K90412 / 5B21J13732 motherboard is the exact replacement you need.
This motherboard is built to meet original specifications, ensuring a seamless fit into your X1 Carbon Gen 10 chassis.
**Core i5-1245U – 12th Gen Performance**
The Intel Core i5-1245U delivers exceptional performance for demanding tasks:
- 10 cores (2 P-cores + 8 E-cores) / 12 threads
- Up to 4.40 GHz Turbo Boost
- Intel Iris Xe Graphics
- Perfect for Windows 11 Pro, Microsoft Office, video conferencing, coding, and multitasking
**16GB LPDDR5 RAM Soldered Onboard**
Unlike other boards that require separate RAM, this motherboard comes with 16GB of LPDDR5 memory soldered directly onto the board. No installation needed. Just install the board and power on.
**Compatibility Check – PLEASE READ**
✅ Laptop Model: Lenovo ThinkPad X1 Carbon Gen 10 (10th Gen)
✅ Motherboard Part Numbers: 5B21K90412 / 5B21J13732
✅ CPU: Intel Core i5-1245U
✅ RAM: 16GB LPDDR5 (soldered, included)
❌ Not compatible with: ThinkPad X1 Carbon Gen 9 / Gen 11 / X1 Yoga
**What's Included**
- 1x Motherboard for Lenovo ThinkPad X1 Carbon 10th Gen (i5-1245U / 16GB)
- Anti-static bag and secure packaging
*Thermal paste, screws, and heatsink/fan assembly are not included.*
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## Shipping & Warranty
**Shipping**
- Free shipping on this item
- Ships within 24-48 hours
- Tracked shipping included
**Warranty**
- 45-day warranty against defects
- 30-day return for DOA (Dead on Arrival) – video proof required
**Installation Note**
This motherboard requires professional installation or advanced DIY skill. We are not responsible for damage during installation.
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## Meta Description (for SEO)
> Buy replacement motherboard for Lenovo ThinkPad X1 Carbon 10th Gen. 5B21K90412 5B21J13732. Intel i5-1245U 16GB LPDDR5. Fully tested. Free shipping. 45-day warranty.
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## FAQ (Optional – can be added to a separate section)
**Q: Does this motherboard come with the CPU and RAM?**
A: Yes. The Intel Core i5-1245U and 16GB LPDDR5 RAM are both soldered onboard and included.
**Q: Is this compatible with ThinkPad X1 Carbon Gen 9?**
A: No. This motherboard is specifically designed for ThinkPad X1 Carbon 10th Gen only.
**Q: What is the difference between 5B21K90412 and 5B21J13732?**
A: These are different revision or FRU part numbers for the same motherboard platform. Both are compatible with X1 Carbon 10th Gen.
**Q: Does the motherboard include the heatsink and fan?**
A: No. You will need to reuse your existing heatsink/fan assembly or purchase separately.
**Q: What if the motherboard arrives dead?**
A: Contact us within 30 days with video proof. We offer DOA replacement under the 45-day warranty.
**Q: Do you offer technical support for installation?**
A: We can confirm compatibility, but we do not provide step-by-step installation guidance.
