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I was given a Presario to fix; it had been dropped on the edge and the power supply jack was damaged. I got a new jack, took out the old one and soldered in a new one.

Now, I've put the unit back together and when it gets past the HP screen, it will go to a blank, black screen and/or just shut down after a few minutes. Note that getting the motherboard to a point where I get at the power jack was a real 'pleasure'. I had a very difficult time of it and would still be trying to get everything apart except for a PDF I found for HP technicians.

When I was testing the machine after I had replaced the jack, I had the machine in a jerry rigged condition (meaning parts were hanging out and no screws had tightened components down) but everything worked correctly; the OS booted (XP), the screen was fine, I could access files and the mouse pad responded properly. The only problem was the sound didn't work and I found out from the owner that had been an issue beforehand. The speaker jack worked and I could use external speakers.

So, I put everything back together this morning. I then rebooted the system. I got the HP splash screen, a black screen with nothing on it and then nothing. I loaded an XP disk in and it booted successfully, but after a while it again shut down without warning.

I've checked the HP site and the best thing that seems to come up is memory reseating. I've done this and even tried memory from another Compaq. The same thing; black screen and/or shutting down.

I took the unit apart again to check for everything. I booted the machine with the cover off and I can see the fans working. To the touch the copper piping gets rather hot, but not what I can gauge as excessively hot.

So? Any hints or suggestions?

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  • Latest Post Latest Post by disophisis

Dani AI

Generated

Quick, prioritized troubleshooting notes that build on description and 's HDD suggestion.

Common causes after a DC-jack repair and reassembly are intermittent power at the board (cold solder, broken trace), a short from a misplaced screw or solder splash, or a connector/cooling element that lost proper contact during reassembly. The next steps are to eliminate the easy suspects first and gather evidence before replacing large parts.

Recommended checks (in this order):

  • Power sanity: remove the battery and test with a known-good AC adapter. Measure the adapter voltage at the jack and at the motherboard input while the machine is under load; wiggle the jack/plug to see if voltage drops or fluctuates.
  • Minimal hardware boot: with cover off, boot with only CPU, one RAM stick, and no HDD/optical drive. Boot to BIOS or external media. If it stays up, add parts back one at a time to find the failing component.
  • External video test: connect an external monitor. If external output remains while internal goes black, suspect the LVDS cable, inverter/backlight or screen connector.
  • Visual and mechanical inspection: look closely (magnifier) at the new jack and surrounding pads for cracked solder, lifted traces, or solder bridges. Check for any loose screws, standoffs, or shielding that could short the board when the case is reassembled.
  • Cooling check: confirm the heatsink/fan are seated and spinning properly with proper thermal paste/contact. Rapid shutdown within minutes can be a thermal cutout if the sink is not contacting the CPU.
  • Data and drive test: if the HDD is suspected, try booting from external media and run a SMART check; remove the drive to see if the shutdown behavior changes.

Safety and data note: back up critical files before destructive tests. If uncomfortable probing voltages or reflowing solder, a repair shop or a technician with stage lighting and a soldering iron is recommended.

Member Avatar for disophisis

If it makes it past POST and doesn't make it to/past the windows splash screen, you might have a problem with your HDD (something may have happened, you never know). Try opening it back up to where it worked before and see if it still works fine that way, then reassemble it and kind of try and test it as you go (if you can, I'm not a big laptop guy so good luck!)

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