The Pegatron M2N78-LA (frequently referred to as the Violet or Violet6) is a Micro-ATX motherboard commonly used in HP and Compaq desktop PCs. Core Specifications Form Factor: Micro-ATX (24.4 cm x 24.4 cm). Chipset: NVIDIA GeForce 9100. Socket Type:
Violet6 (Rev 6.01): Socket AM3 (Supports AMD Phenom II, Athlon II, and Sempron processors).
Earlier Revisions: Socket AM2+ (Supports Phenom, Athlon X2, and Athlon 64 X2). Memory:
Four DDR3 DIMM slots (Violet6) or DDR2 (earlier versions). Supports up to 16 GB on 64-bit operating systems. Speeds: PC3-10600 (1333 MHz) or PC3-8500 (1066 MHz). Key Connectors & Layout
The layout follows standard Micro-ATX configurations with the following key headers: Expansion Slots: 1x PCI Express x16 (for a dedicated graphics card). 2x PCI Express x1. 1x PCI slot. Internal Storage: 4x SATA connectors. Power: 1x 24-pin ATX power connector. 1x 4-pin ATX P4 connector (12V).
Front Panel: Connectors for Power, Reset, HD LED, and Power LED. Maintenance Procedures
Clearing CMOS: Locate the CLEAR_CMOS jumper. Move the jumper from pins 2-3 to pins 1-2 for 5-10 seconds, then return it to the original position.
Resetting BIOS Password: Use the CLEAR_PW jumper. Follow the same procedure as clearing the CMOS to erase the stored BIOS password. Motherboard Specifications, M2N78-LA (Violet6)
: If three or more modules are installed, DDR3-1333 will downclock to 1066 MHz due to AMD controller limitations. Earlier Revisions
: Some versions use DDR2 memory (PC2-6400/800 MHz or PC2-5300/667 MHz). The Retro Web Internal Connectors & Slots 1x PCI Express x16 (for graphics). 2x PCI Express x1. 1x PCI slot. 1x PCI Express x1 mini card socket. : 4x SATA connectors. : 1x 24-pin ATX main power and 1x 4-pin ATX CPU power. Rear I/O Ports : 1x VGA and 1x DVI. : 4x USB 2.0 ports. Networking : 1x RJ-45 Ethernet (Realtek RTL8201N 10/100 Mb/s).
: 6-port audio jack (Realtek ALC888S 8-channel HD audio) and 1x S/PDIF coaxial out. : 1x IEEE 1394 (FireWire). Maintenance & Jumper Settings Clear CMOS Turn off the PC and unplug the power cord. CLEAR_CMOS jumper to pins 1-2. Wait 5–10 seconds, then return it to pins 2-3. Clear BIOS Password : Locate the
jumper. Move from pins 2-3 to pins 1-2 for 10 seconds, then return. Front Panel Header
: A 9-pin header handles the power button, reset, and LED indicators. Polarity matters for LEDs but not for the power/reset switches. device.report
Full manual PDFs and driver updates can often be found through the HP Support Portal
by searching for your specific desktop model number (e.g., Pavilion p6130f) or via legacy archives like The Retro Web pinout diagram for the front panel or a specific list of compatible AM3 CPUs Motherboard Specifications, M2N78-LA (Violet6)
Pegatron M2N78-LA (also known as the ) is a micro-ATX motherboard commonly used in HP and Compaq desktop PCs. device.report
Depending on your specific revision, this board may support either (DDR3) processors. The Retro Web 🛠️ Essential Manual Details You can find comprehensive setup information in the HP M2N78-LA Motherboard Manual Violet6 Specifications Guide Front Panel Header Pinout The front panel header (
) is typically located on the lower right edge of the board. While HP motherboards often use a proprietary block connector, you can manually wire individual case leads using this common layout: HP Support Community Pin Function Color (Typical) Power Button Green / Blue White / Yellow Jumper Settings Clear CMOS: CLEAR_CMOS
jumper from pins 2-3 to pins 1-2 for 5–10 seconds, then return to the original position. Clear Password: CLEAR P.W. pegatron motherboard m2n78la manual top
jumper to pins 1-2 for 10 seconds while the power is off to reset the BIOS password. Auto Power On:
header to enable or disable the PC starting automatically after an AC power loss. Key Specifications Form Factor: Micro-ATX (24.4 cm x 24.4 cm). NVIDIA GeForce 9100. Expansion: 1x PCIe x16, 2x PCIe x1, 1x PCI, 1x Mini-PCIe. 4x SATA II connectors. Integrated Realtek ALC888S (8-channel HD). The Retro Web Motherboard Specifications, M2N78-LA (Violet6)
The dust motes dancing in the single shaft of afternoon sunlight were the only movement in the entire garage. Elias stood on the toes of his worn sneakers, straining upward, his fingertips brushing against the rough edge of a cardboard box labeled "MISC. ELECTRONICS - 2009."
It was the top shelf—the graveyard of forgotten hardware. This was where good computers went to die, or at least to gather a thick, grey coat of time.
"Come on," Elias grunted, shifting his weight. He was trying to resurrect a vintage gaming rig for a client who wanted the specific, raw sound of a 2008-era sound card. He had the card, he had the case, but he needed the proprietary motherboard he knew was buried somewhere in this chaos.
His fingers hooked around a plastic lip. He pulled. It was heavier than expected. A cascade of anti-static bags and tangled IDE cables tumbled down, but Elias ignored them. He had spotted it.
He climbed down the stepladder and brushed the dust off the object in his hands. It was a motherboard, vintage green PCB, capacitors bulging slightly with age. Silkscreened in faint white text near the CPU socket was the model number: M2N78LA.
"Ipswich," Elias whispered, reading the HP codename. "OEM special."
He set the board on his anti-static mat and reached for his power supply unit. He plugged in the 24-pin connector, then the 4-pin CPU power. He hit the switch on the back of the PSU.
Silence.
He pressed the power pins with a screwdriver. A faint whine from the PSU, a fan twitched, but nothing happened. No post, no beep, no life.
"Capacitors look fine," he muttered, grabbing his multimeter. He probed the voltage rails. The 12V was dropping to 9V almost instantly under load. A short? Or maybe a front panel header issue?
He rummaged through the pile of debris that had fallen from the shelf. He found the I/O shield and a driver CD, but he needed the layout. He needed to know exactly which pin was the ground on the USB header, or if the CMOS battery was dead. He was flying blind.
He looked back up at the top shelf. There has to be a manual.
He climbed back up. He pushed aside old modems and sticks of DDR2 RAM. Finally, wedged between a broken printer and a stack of floppy disks, was a thick, glossy booklet. It was the Pegatron M2N78LA Manual.
He climbed down and flipped it open. The smell of old paper filled his nose—a comforting scent of vinegar and pulp. He skipped the safety warnings and went straight for the schematics. He traced the power routing with his finger.
Page 12: Jumper Settings.
Elias froze. He looked at the board, then back at the manual. There, in the diagram for the memory voltage regulator, was a jumper labeled 'JV1'. The manual showed it in the default position. He looked at the physical board. The jumper was missing entirely. The Pegatron M2N78-LA (frequently referred to as the
He must have knocked it off when he pulled the board from the shelf.
He found a spare jumper in his parts bin—a tiny, seemingly insignificant black plastic shunt. He placed it carefully over the two pins designated in the manual, bridging the connection.
He held his breath. He shorted the power pins again.
Whirrrr.
The CPU fan spun up, a steady, reliable hum. The heatsink grew warm. On the monitor sitting on the workbench, a cursor blinked, followed by the glorious, blocky white text of the BIOS screen.
ASUSTek Computer Inc. M2N78LA BIOS v5.07
Elias slumped back in his chair, exhaling a breath he didn't know he was holding. He looked at the manual, resting open on the desk. It was just a book of paper and ink, a guide for a piece of technology considered obsolete by the world.
But as the familiar beep of a successful POST echoed through the garage, Elias patted the cover of the manual. It wasn't just a book; it was the map to a treasure buried on the top shelf, brought back to life by a tiny black jumper and a page of diagrams.
He carefully closed the manual and placed it on the reference shelf, right at the top, where it belonged.
The Pegatron M2N78-LA motherboard (OEM engineered for HP under the codename Violet) is a popular but aging piece of hardware that requires some technical know-how to maintain. 🛠️ Essential Pegatron M2N78-LA Manual & Setup Guide Core Hardware Specifications Form Factor: Micro-ATX (24.4 cm x 24.4 cm) Chipset: NVIDIA GeForce 9100
Expansion Slots: 1x PCI Express x16, 2x PCI Express x1, and 1x standard PCI slot
Rear I/O: 4x USB 2.0, 1x DVI, 1x VGA, and standard 8-channel audio jacks Navigating the DDR2 vs. DDR3 Confusion
You must check your motherboard's revision number before buying any memory.
Older Revisions (e.g., Rev 3.02): These rely strictly on DDR2 memory (up to 800MHz) and Socket AM2 processors.
Newer Revisions (e.g., Rev 6.01): These support DDR3 memory (up to 1333MHz) and Socket AM3 processors.
Limit: Both versions max out at a ceiling of 16 GB on 64-bit systems. ⚠️ Top Troubleshooting & Maintenance Tips The Notorious Chipset Overheat
The most common hardware failure on the M2N78-LA involves the NVIDIA MCP78 chipset. It handles your SATA storage connections but ships from the factory with an undersized heatsink.
The Symptom: Your PC will fail to boot or randomly stop recognizing your hard drives. The PC health status displays the system health information
The Fix: If your board still works, consider sticking a small active cooling fan or a larger aftermarket heatsink directly onto that chipset to keep it alive. Quick Jumper Configurations
If you cannot locate the complete manual for the OEM board, keep these two critical jumper locations in mind for troubleshooting:
To Clear CMOS (Reset BIOS): Find the jumper labeled CLEAR_CMOS. Move it from pins 2-3 over to pins 1-2 for roughly 10 seconds, and then place it back where it was before booting up.
To Clear BIOS Password: Locate the CLEAR P.W. jumper. Move it to pins 1-2 for 10 seconds, return it to pins 2-3, and power the machine on. Flashing the BIOS Pegatron M2N78-LA mobo memory - Tom's Hardware Forum
I discovered this little issue myself on my hp s5260f w/a M2N78-LA Violet6 6.01 motherboard... seems its an AMD CPU known problem; Tom's Hardware
Important Note: Pegatron is an OEM manufacturer (they make boards for HP, Compaq, Asus, etc.). There is no standalone retail manual from Pegatron for the M2N78LA. This board is almost exclusively found inside pre-built computers, most commonly the HP Pavilion p6000 series and Compaq Presario CQ5000 series.
However, you can access the official HP maintenance and service guide that contains the exact motherboard layout, BIOS settings, jumper settings, and troubleshooting for the M2N78LA.
If you have landed on this page, you are likely wrestling with a frustrating reality of the PC repair and upgrade world: you own an OEM computer (likely an HP or Compaq desktop from the late 2000s) that houses a Pegatron M2N78LA motherboard, and you cannot find the official manual. You are searching for the "Pegatron motherboard M2N78LA manual top"—meaning you want the definitive, best resource for information, jumpers, BIOS settings, and header pinouts.
You have come to the right place.
While Pegatron (a spin-off of ASUS) produced millions of these reliable AM2+ boards for mass-market desktops, they rarely published standalone manuals for end-users. Instead, these manuals were buried inside proprietary HP support documents. This article serves as the top manual replacement. We will cover every specification, connector, jumper setting, BIOS beep code, and upgrade path you need to keep your vintage system running.
The PC health status displays the system health information.
5. Software Installation
This section will guide you through the installation of the motherboard drivers and utilities.
First, let’s address the elephant in the room. Why can’t you just download a PDF called M2N78LA_Manual.pdf?
Pegatron is an Original Design Manufacturer (ODM). They build boards for companies like HP, Compaq, and Acer. Therefore, the M2N78LA was never sold at retail. It appeared in models like the HP Pavilion p6000 series, Compaq Presario CQ5000 series, and some HP Slimline s5000 models.
When you search for the "manual top," you are looking for the mother of all guides—the top-down resource that explains the board layout. Since the original HP manuals are often stripped down (lacking CMOS clear jumper locations or RAM population rules), this guide will fill in those gaps.
Cause: The BIOS is trying to boot from the network because it cannot find your hard drive. Fix: Enter BIOS > Advanced > Onboard Devices > Network Boot ROM set to [Disabled].
The advanced menu allows you to configure the advanced settings.
Yes. The top workaround: You must install via Legacy BIOS (not UEFI). Use the NVIDIA nForce Driver v15.56 (modified) for SATA and LAN. Sound requires a Realtek HD Audio driver from 2015.