If you run a small office or a home study, the HP ProDesk 400 G7 on your desk may have gone completely silent: no power light, no fan, nothing on screen. You press the button again and again. Is it the power supply, the board, or something simple like a socket? This post gives safe checks you can do in ten minutes, explains what a diagnosis will decide, and helps you pick between HP coverage and an independent repair.
Is it the power supply, the board or something simpler?
Short answer: First rule out the simple causes: the wall socket, the power cable, the switch on the back and the display cable. If the desktop is still silent, a technician tests the power supply, the memory (RAM) and the main board (motherboard) in turn. Use HP coverage first if a warranty or Care Pack is active.
Safe checks before you call anyone
- Try another wall socket. Plug in a lamp or phone charger to confirm the socket has power. A power cut or a tripped extension board is common.
- Check the power cable and the back switch. Press the cable in firmly. If your model has a switch or a small light on the back, note whether it lights.
- Remove extras. Unplug USB drives, printers and other devices, then try the power button again.
- Check the display. A desktop can be running while the monitor shows nothing, so look for fan sound and lights.
- Wait a minute. After a power surge, some power supplies need a short rest with the cable unplugged before they restart.
Do not open the case with the cable plugged in, and do not touch the power supply box inside. It holds charge that can hurt you, and opening it may also affect warranty terms. If a part smells burnt, leave it alone and book a diagnosis.
What the diagnosis will decide
Power supplies differ between models, so a technician checks your exact machine before quoting. See our desktop will not power on guide for more on how a supply fault shows up.
The HP route, fairly
If your ProDesk is within its warranty, or you bought an HP Care Pack that is still active, start with HP. That is the route designed for covered faults. For HP's options when the desktop is out of warranty, ask HP or check HP's support page, because the process and charges depend on your model and country. Our HP service centre vs independent repair page sets the two routes side by side, and the HP authorised vs independent service post covers HP in general.
What Laptop Repair World can do
Laptop Repair World is an independent repair shop, founded in 2007, with one store at MG Road, Secunderabad. We are not an HP service centre and have no tie-up with HP. For a silent desktop we can test the power supply, the RAM and the board, and quote in writing after diagnosis. See HP desktop repair for the work we handle.
- A written quotation listing parts, labour, GST and the visit fee before any work.
- If testing finds another fault, a revised quotation is approved before any further paid work.
- Each part named as original, compatible or refurbished, with its own warranty.
- A handover test, so you see the desktop start, with a short written record of the work.
Same-day completion is possible only for eligible jobs, when the part is on hand and a technician is free. It depends on the part and the fault.
Power cuts and voltage swings in Indian offices
Frequent power cuts, loose extension boards and voltage swings are hard on a desktop power supply. A surge protector or a UPS (a small battery unit that smooths power) lowers the risk. Avoid plugging a desktop into a shared board with a heater or air conditioner. For doorstep service in the city, see our HP desktop service in Secunderabad page.
A typical case (an illustration, not a real customer)
Picture a small accounts office with a ProDesk that stopped overnight after a storm. The owner tries two sockets and another cable with no change. A technician finds the power supply gives no output, fits a new one, and shows the desktop starting at handover. Had the supply tested fine, the board would have been checked next, and a revised quotation approved before further paid work.
Which route makes sense?
When to get help
- No light or fan sound after the safe checks above.
- The desktop starts, then switches off within seconds.
- There was a burning smell, a pop or a spark.
- The desktop works only after many button presses.
Start with HP desktop repair. For a doorstep visit, there is a ₹149 doorstep visit fee, waived when you approve laptop repair with us. No Fix No Fee covers the repair charge if the fault is not fixed, while the visit fee is waived only when you approve the repair.
A note from the LRW Engineer Team
Before any visit, write down what happened just before the fault, such as a power cut, a storm or a new device. Take a photo of the back of the desktop. Keep important files backed up, because a board fault can put the drive out of reach until the desktop is repaired.