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Hi, I have a Sony VAIO Laptop VGN-NR21M/S which has been working fine. The only problem was the battery wasn't holding it's charge and I was planning to buy a new one. Last night it shut down while I was running Virtual DJ software. No warning, no error message or blue screen. Just shut down. It won't start up if the battery is in, and if I run an AC only it works for a while and then shuts down in the same way.
I've run hardware tests and they say the CPU and memory are fine. The computer shut down while testing the hard drive, but as it's only a few months old I'm hoping thats not the cause. The Laptop is running vista 32 bit, but I'm sure it's not an OS problem as I have formatted the drive and there is no OS on there at the moment. Any help apreciated.

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Note: this brief expert addendum ties together the troubleshooting already performed by and the suggestions from , and gives a compact, practical checklist for anyone seeing sudden shutdowns or complete no-power on a VAIO or similar laptop.

A short isolation checklist to follow before any board-level work:

  1. Inspect the AC adapter and cable for cuts, kinks, exposed wires or a hot/charred smell.
  2. Measure the adapter with a multimeter (DC volts). First measure the adapter unplugged from the laptop to confirm the open-circuit value matches the label. Then measure it while connected and attempting to power on the laptop — a substantial drop while loaded indicates the adapter is failing.
  3. Confirm behavior with a known-good adapter that matches the laptop’s required voltage and has equal-or-higher current rating. If the machine runs reliably with a known-good unit the original adapter is the fault.
  4. With the battery removed, wiggle the DC plug gently while powered: if power cuts when the plug is moved, suspect the barrel/DC jack or its solder joints.
  5. If a good adapter still gives no power, inspect the DC jack and motherboard for visible damage, blown capacitors, or cracked solder; a blown input fuse or MOSFET on the power board is a common repair.

Replacement and safety notes: match the adapter voltage exactly, use an adapter with equal-or-higher amperage, ensure correct polarity and connector size, and prefer OEM or reputable-brand replacements with protection features. Always unplug mains power before opening the case, use insulated probes, and avoid probing mains components unless experienced. If the DC jack or internal power parts are suspected, a qualified repair shop is recommended unless proper soldering and diagnostic tools are available.

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Member Avatar for cuivenion

Some additional info I cleaned the inside and the fan about 2 months ago so I don't think its a overheating issue.

Member Avatar for timtekrepairs

When you cleaned out the heatsink did you also replace the thermal compound? Did you clean out the heatsink because it was over heating? How many times / how long. The MB can warp sometimes.

Member Avatar for cuivenion

I didn't move the heatsink at all so the thermal compound hasn't been touched. I cleaned the insides plus the fan and filter with compressed air and it's been working fine for a while since. The Laptops now completely dead won't start at all. I'm really hoping it's a faulty power supply. I'm going to pick up a multimeter tomorrow to test it.

Edited by cuivenion
Member Avatar for cuivenion

Ok I've tested the charger (19.5v) and it's reading 15.78v. so I'm a bit stumped. I've tested two other chargers known to be working and they're reading as expected, slightly above their working voltages.

Member Avatar for cuivenion

It was a faulty charger.

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