Use ATX PSU With HP Proprietary PSU Desktop (& Add a GPU)

Many HP Desktops come with a proprietary PSU. These PSU's are often low wattage, leaving little room for system expansion. A higher wattage PSU can be purchased but they are usually overpriced & not the best quality.

A PSU upgrade will allow you to add a more powerful Graphics Card (GPU) to your system, some extra hard drives, or even just replace a broken one on the cheap.

Many of the HP desktops can be booted with a standard ATX PSU but it requires the PSU's green wire to be always shorted resulting in the PSU always running. This is fine for many, but can causes issues with GPU's. Luckily we can fix this problem. Just follow this guide.

This guide will only work with HP PSU's that used 2 x 4 Pin connectors for power & a 7 pin connector for the motherboard. Does not matter how many of the 7 pins are used, will work for any configuration. (See step 1 for help). It will not work with 6 pin power connector HP power supplies

Compatible PSU Models:

• D16-180P2A*
• PA-3401-1
• DPS-310AB
• D19-180P-1A*
• & many others

*= Personally Confirmed

Only a few basic supplies are needed. I purchased all mine for under $10 from China.

Many of the pieces can be substituted depending upon what you desire.

Materials:

1: ATX PSU:

• Can be ATX, TXF, Flex ATX, Pico PSU, etc. As long as follows ATX standard.
• Look for at least 2 amps on the 5v VSB rail. Should not be a problem on modern supplies.
• The HP desktop will be powered solely off the 12v rail unlike most PC's. As GPU's also rely on the 12v rail look for a supply with a hefty 12v rail rating or multiple 12v rails.

2: Boost converter:

• I used a MT3608. Xl6009 is another common choice. Look for one that supplies at least 1 amp on output.
• If using USB ports while PC is off/asleep one with higher amperage is recommended.
• Needs to work with a 5v input & 12v output. Most should suffice.

3: 4-PIn CPU Power extension cable:

• Make sure to get one long enough to reach from the converter board you are going to make to the 4 pin connector on the motherboard closest the 7 pin connector.
• You will only need the male end, so any cable with a male 4 pin connector will suffice. Can even cut one off the original HP PSU.

4: 2 x relay modules:

• 2 are needed. Can purchase a board that is two stuck together.
• One needs to be 5v(trigger signal) and have the option to be triggered on a LOW signal. Usually via a jumper.
• Other relay can be either 5 or 12v. 5v is easier & preferred but 12v can be done.
• Most budget relay modules are rated at 10 amps. 2 x 10 amp relays will provide the motherboard with 240 watts, likely more then the original PSU. That should be fine for most cases. I made an adapter using a 30 amp relay, giving 480 watts, so would not worry if using a power hungry GPU.

5: ATX Female plug/board

• Just needs to be a female ATX plug(Same as on motherboard). I purchased one designed to run 2 ATX supplies in 1 PC. Search "Dual power Supply Sync Adapter".
• An extension cable will also work fine.
• Be careful if purchasing a ATX breakout board as they often do not break out the PWR OK & 5v VSB lines which are needed.

6: 1000uf capacitor (or larger):

• Value is not critical. I found 1000uf to be the minimum required for my PC. More power hungry machines may require a bigger value. . Bigger value will not hurt, smaller value will not work.
• 16v minimum. Higher is okay.

7: Some type of header/Dupont wires:

• Need to connect a minimum of two wires to the 7 pin connector on the HP motherboard. Dupont connectors or servo wires will fit or you can buy the correct header. I do not know the specs of it,
• You also can cut the original one off the HP PSU.

8. Scrap Wire:

• Varying lengths needed. Various colors help but not required.
• I used 16 AWG from an old PSU for the 12v, Ground, & boost. Used 22awg for relay power & signals.
• Thicker is better for the 12v PWR & Ground. Other lines are okay with a smaller gauge, just don't skimp.

9: Mounting Block & Screws

• You are going to want to screw all your components down to make it neater. I used a scrap piece of wood. Use whatever you want, just make sure it is not conductive.
• If your tech savvy print up a PCB :)

Tools:

1: Small Screwdrivers:

• The relays have small screw blocks. A small Philips & flat headed screw driver is needed.
• Also used to screw down boards to mounting block

2: Wire Strippers/Scissors:

• Someway to strip & cut the wire to length.

3: Solder Iron & Solder:

• Needed if attaching wires to ATX board, boost converter, & capacitor. Never hurts to solder any other connections may have too.
• My soldering skills are horrible but I managed, so can you!

4: Multimeter

• Never hurts to check things before plugging into PC. Debugging too. Any one will do.
• If you don't have one, go buy one. You will not regret it.

How it works (Original HP PSU):

The original HP PSU is always on & constantly outputs 12v to the two 4 pin connectors. This is the equivalent of keeping the green & black lines on an ATX PSU always jumped.

The 4 pin connector closest the 7 pin is special as it is connected to the power button. When the power button is pushed the motherboard pulls pin #4 (PWR_ON (Green wire)) to ground. Pin is default 3.3v. Pin stays at ground until the PC is shut off via OS, the button, or power is lost. The 4 pin must always have a 12v source.

Pin #3 (PWR_ID (Grey wire)) on the 7 pin connector is the equivalent of the grey ATX PWR_OK. If the line is never OK (High) the PC wont boot. This wire must be connected directly to the ATX PWR_OK wire.

The pins on the 7 pin connector are:

#1 Ground (Black wire)

#2 PWR Meter (Purple wire)

#3 PWR_ID (Grey wire)

#4 PWR_ON (Green wire)

#5 Ground (Black wire)

#6 Fan_Tach (White wire)

#7 Fan_CMD (White & red striped wire)

Not every PSU used all the pins. Some only use 3 (GND, PWR_ID, PWR_ON)

How this project works:

2 relays are used. Both relays are powered off the 5v VSB line of the ATX PSU.

Relay #1 connects the PWR_ON & Ground wires of the ATX PSU to turn it on. This relay gets its trigger signal from Pin #4 of the 7 pin connector. This relay has the jumper configured to enable on LOW.

Relay #2 has the common(com) terminal connected to the 4 pin connector closest the 7 pin connector on the motherboard. The normally closed (NC) terminal is connected to the output of the boost converter. The boost converter input is connected to the 5 vsb line on the ATX PSU. The normally open (NO) terminal of the relay is connected to a 12v line of the ATX PSU. The capacitor is connected in parallel with the normally open terminal. The relay gets its trigger signal from a 5v line on the ATX PSU(Not the standby).

The boost convert supplies a constant 12v source to the 4 pin. When the power button is pressed relay #1 is activated which switches on the ATX PSU. Once the PSU is on it activates relay #2 which connects the ATX PSU's 12v lines to the motherboard, cutting off the boost converter's line. A small interrupt of power occurs, which is minimized with the capacitor.

Modify it however you want! Hopefully my explanation & diagrams will give you a solid understanding of how it works.

Extra Info:

• The 12v lines used to power the motherboard can be taken from anywhere on the ATX PSU. I used the ATX connector but you can use any Sata, Molex, 6 pin, 8 pin, etc. A good idea is to split the CPU 8 pin (4 + 4) plugging one side into the CPU 4 pin connector & the other into the adapter board. If you purchase a 4 pin CPU power extension cable you can cut it right in half & have all the connectors you need.

• I designed my adapter board to fit in the 2.5" HDD bay of my case. My mounting board is roughly the size of a 2.5" drive and mounts using the original holes. You can put yours wherever.

• The Molex & Sata wires from new PSU can be used to add additional drives and/or to take load off the 12v line of motherboard as it has 5v converters for the HDD's onboard.

Some Ideas:

• Get a custom PCB made to minimize the mess.

• Try it with MOSFETS or transistors. Definitely are a better idea then relays.

• Try to fit it all inside your ATX PSU or the ATX guts & adapter in the original HP PSU. Would look great finished.

• Use the relay attached to the ATX PSU board. Can be done just wasn't worth my time.

• Use fork terminals on the relay terminals rather then just sticking wire in.

• Make a full covered enclosure for the adapter board.

Some Suggestions:

• If using a PicoPSU you can eliminate the boost converter. Just tie the 12v from power brick directly to the relays normally connected terminal.

• Can use a PicoPSU with the original HP PSU as a power source.

• A dual relay board would be smaller & neater. Would require less wiring. A worthwhile suggestion.

• Try to be neater then I am.

Other ways to wire:

This whole project can be made without soldering. Just purchase an ATX extension cable & a boost converter with screw terminals and wire it up. You also could cut the plugs directly off an ATX supply and splice them back together as needed.

Wiring is quite simple. Follow the images for guidance.

Diagrams are all the same concept. They are just tweaked for different relay types & power sources. Feel free to tweak to fit your needs.

If you chose to use a dual power supply adapter for the female ATX plug such as I did here is how I soldered it. You can use different pins for the 5v, & Ground. The 12v does not need to be attached to here. I did it simply due to ease.

Hooking up the adapter board to the HP motherboard is simple.

1. Plug the 4 or half the 8 pin(4+4) pin connector(Depending upon your ATX PSU) into the 4 pin connector of the motherboard nearest the CPU.

2. Plug the 4 pin connector from the newly made adapter board into the 4 pin connector closest the 7 pin connector on the motherboard.

3. Connect the 2 pins from the breakout board (PWR_OK & the signal for relay #1) to the corresponding pins on the 7 pin connector of the motherboard. See steps 1 & 3 for help.

4. Connect the 24 pin ATX connector of the ATX PSU to the adapter board.

5. Attach any 6/8 pins to GPU or Sata/Molex connectors to HDD/SSD's.

Now turn on the PC using the power button. Relay's should click & PC will power right up! If not see Step 7 Debugging.

On some HP PSU's the PSU fan is used as a system fan. This is the case as in the Elitedesk 800 G3. Without this fan present the PC will throw an error 90E saying a PSU fan is not present. The PC will still boot but the error is annoying.

The PSU fan communicates with the motherboard via Pin #6 (Fan_Tach) on the 7 pin connector. This pin is simply looking for a Tach signal from a fan. You have a few options:

• Run a jumper wire from a different fan in the PCs Tach pin to pin #6. Any fan will do. Even the CPU fan.

• Rig up a fan to the PC. Just add it a fan and wire it up. Tie into the 12v & Ground from the ATX PSU to power the fan. Connect the Tach pin to Pin#6 on the 7 pin connector. Fan will always run full speed.

• Add a fan controller. Wire it up however. Just connect one of the Tach pins to pin #6 of the 7 pin connector.

• Add a Tach controlled fan to the ATX PSU. Remove old fan from PSU & swap in a new 3 or 4 pin fan. Run a wire outside case for the Tach connection. CAUTION: Be careful when opening an ATX PSU. High voltages are present & lethal.

Both 3 & 4 pin fans will work. Attached is a diagram showing the corresponding pins. On a 4 pin fan the PWM pin will remain unused.

If your PC will not start up with the new adapter board there could be a few things wrong. Here are some of the common issues I found.

PC tries to boot but immediately powers down:

• Make sure all wires are tightly connected and the 4 pin connectors are seated all the way.
• Make sure you have the capacitor connected in parallel with the 4 pin closest the 7 pin.
• Try a larger value capacitor.
• Make sure the boost converter is set to 12v. A lower voltage will cause it to not boot. If using a 12v relay it may not fully trigger.
• Try a larger gauge wire. Too thin a gauge will not pass enough current.

Relay keeps triggering/light flashes:

• Double check all wiring.
• Specifically check to make sure you have the wires connected correctly & securely in the 7 pin connector. Reversed or missing wires will cause this.

Red Light on HP Power Button:

• Power supply is not providing enough power.
• Check all wiring and connections. Loose CPU connector can cause this.
• Make sure the ATX PSU has enough wattage on the 12v rail.
• Try using a larger gauge wire.

Fan Running Full Blast:

• Check to see if connected the Fan_Tach pin on the 7 pin connector. Without it fan will run full speed constantly.

Things to note:

Some ATX PSU's will not work properly without a load on the 5v rail. A normal motherboard loads this rail, but the adapter used in this guide will not. If so, a dummy load may be need on the 5v rail. A 10 ohm, 10 watt resistor is common or an incandescent automotive style light bulb may be used. A few old HDD's will also work.

Many images were taken by me. Those that were not are from the following sources:

ATX PSU:

https://www.computeralliance.com.au/power-supplies

HP White Desktop:

https://www.hp.com/us-en/shop/pdp/hp-pavilion-desktop-tp01-3025t-bundle-pc

HP Elitedesk:

https://www.amazon.com/HP-EliteDesk-800-G3-DVD-Writer/dp/B01N27S6NF

Dupont Wires:

https://www.rexqualis.com/product/120pcs-multicolored-dupont-wire-40pin-male-to-female-40pin-male-to-male-40pin-female-to-female-breadboard-jumper-wires-for-arduino-raspberry-pi-2-3/

Capacitor:

https://www.amazon.com/5pcs-1000uF-Electrolytic-Capacitors-11X18/dp/B07GCV44GM

Solder Iron:

https://www.temu.com/8pcs-digital-display-80w-electric-soldering-iron-kit-180-450-degree-adjustable-adjustable-temperature-button-for-electronic-diy-kits-with-5-tips-solder-wire-tip-cleaner-g-601099522270700.html?top_gallery_url=https%3A%2F%2Fimg.kwcdn.com%2Fproduct%2FFancyalgo%2FVirtualModelMatting%2F62a3507a041fc03206f61f3bfe05fb3a.jpg&spec_gallery_id=2017308108&refer_page_el_sn=209279&_x_vst_scene=adg&refer_page_name=kuiper&refer_page_id=14021_1709387679185_vj7opa1mvb&refer_page_sn=14021&_x_sessn_id=02georuj7y

Screw Drivers:

https://i.ebayimg.com/images/g/x1QAAOSwGqtjxGly/s-l1200.jpg

Scrap Wire:

https://png.toolxox.com/pngi?p=wTioxo_wire-png-electrical-wire-clip-art-transparent-png/

MultiMeter

https://www.superiorelectric.us/superior-electric-t3000-digital-multimeter-ac-dc-volt-test-volt-ohm-meter-vom

Wire Strippers:

https://www.lowes.com/pd/IDEAL-Wire-Strippers/3370008

Pico PSU:

https://www.amazon.com/Mini-PicoPSU-150-XT-DC-DC-power-supply/dp/B0045WFZSQ

3 vs 4 pin fan diagram:

https://www.cgdirector.com/3-pin-vs-4-pin-pc-case-fans/

PCB:

https://www.wevolver.com/article/trace-pcb-a-comprehensive-guide

ATX Breakout Board:

https://www.ebay.com/itm/224599257814

ATX Extension Cable:

https://www.amazon.com/StarTech-8-Inch-Power-Extension-ATX24POWEXT/dp/B000FL60AI

HP 6 Pi

HP 7 Pin plug:

https://superuser.com/questions/1713585/how-did-hp-made-their-power-on-bottom-work-with-no-vsb-standby-on-their-pro-29

HP 3 Pin Plug:

https://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/Power-Supply-Upgrade-for-an-HP-590-P0033W/td-p/6987299

Circuit schematic was created in: Fritzing.

The original design & circuit layout is 100% original to myself. Pinouts & functionality was discovered by disassembly & probing of the original HP components. No 3rd party was involved.

Hope this has helped out some people.

Feel free to comment with any questions/suggestions. Will do my best to answer & help out!

Also if you know models of HP PSU's this works with please comment them so I can add to list.