1 HP Laptop Not Booting After Fan Clean Disassembly - Caps Lock Blinking
I have an HP Pavilion laptop, a 2012 Model # dv6-7013cl, approximately 6 years old, and out of warranty since 2014. When turned on, the caps lock flashes continuously - no blink code - and the F12 orange button light stays on. It will not boot or show anything on the screen.
The laptop previously worked without issues other than overheating easily. For this reason, I disassembled it and cleaned the fan. There was a layer of lint inside the fan housing so thick that I at first thought it was a foam filter strip. After removing the lint and cleaning off dust with brushes and ear swabs, I reassembled everything and found the laptop in its current no-boot state.
The fan runs and blows warm air, and at a much better rate since being cleaned. The computer will power on with only the battery, with only the power cord, or both, and the screen flashes for a fraction of a second before going back to dead black and beginning to flash the caps lock light. I have since disassembled and reassembled the laptop at least four times and left it charging overnight without any change in its condition. I've quadruple-checked for missed connectors, board damage, etc. and found none.
NOTES:
(1) Because the CMOS battery is fit tightly into the laptop's plastic frame, I had to disconnect it in order to remove the motherboard and the fan for cleaning. Thus the BIOS was reset on an old battery.
(2) I initially misseated the memory cards, but found this problem and fixed it before the second reassembly. Reseating the memory cards multiple times has not changed the problem. I used photos prior to disassembly to ensure that they were replaced in their original slots.
(3) I have read through and followed all relevant sections of the HP Support Document "Computer Does Not Start and Emits an LED or Beep Code" found at https://support.hp.com/ph-en/document/c0.... The caps lock key is NOT blinking a code; it is blinking continuously at a rate of about 1 blink per second.
Besides reseating the memory cards, I've tried the "Hard Reset" described in the HP Support Document. I've also tried the ever harder reset described here on IFixIt: Caps Lock and Num Lock LEDs blink continuously, can't get to BIOS
I am seeking diagnostic and repair suggestions from people with ideas. I appreciate all help and will follow and report back on any suggestions that are provided.
Thank you!
Ist dies eine gute Frage?
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Hi @fanattick
Do you have multiple memory installed?
If so, try testing with one piece first, check the contacts of the RAM, the gold surface should not be oxidise or contaminated.
von Augustine
Hello @Augustine
The computer came from the factory with two memory cards. I tried removing one, then the other, and powered up the computer with no difference. An inspection of the cards found no dirt or damage; they look brand spanking new. Even the bar code papers glued to the cards are not yellowed with age.
Thanks for giving me an idea.
The HP Support document suggests that this kind of boot failure could be due a CPU, GPU, motherboard, memory card, or BIOS corruption/authentication failure. I wonder what is most likely...
In any case, I guess having a boot disk would not help in this situation.
von Mike Brenner
On the advice of a person on another board, I disconnected everything but the monitor, fan, and a RAM card, and tried to get the laptop to POST. I was unable to get it to POST in any configuration. I'm starting to think that the misseating of the memory cards or some other careless slip may have caused a short circuit or severed a connection.
Does anyone think this could be the case? If so, is there a good online guide anyone could recommend for how to check a motherboard for short circuits? I've got a multimeter, magnifying glass, etc.
von Mike Brenner
Hi @fanattic ,
You stated that you mis-seated the memory cards. Was this both modules or only the 1, (you said that there were two)?
Have you tried starting the laptop with NO RAM installed? At least to see if you get a different condition showing e.g. RAM failure or No RAM etc. in lieu of what you get now.
Just a thought.
von jayeff
Hi @jayeff
While attempting to get the laptop to post, I did try to start the laptop with both RAM cards removed. There was no change in symptoms.
I've since learned from an HP Support agent that the constant caps lock blink most likely indicates a faulty CPU. This could've happend because the thermal paste, which appears to be silver-based, leaked onto some of the external components. Perhaps this, combined with whatever jostling occurred during the heatsink removal, caused the CPU failure.
I'm also concerned about a metal Z-shaped spring that's making contact with the copper heatsink tube near the fan. I didn't notice if this spring was insulated from the copper tube or not by some foam tape that I had to remove to disassemble and clean the fan. Do you think it could have caused a short circuit? I have no idea if this spring carries an electrical current or not, and am worried it could short a replacement CPU.
I've posted a couple pictures at this link:
https://imgur.com/a/I7ix9
von Mike Brenner
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