The power adapter is delivering 19 volts to the DC jack on my GATEWAY MT6832b notebook but the notebook shows no sign of life. I have removed the motherboard in order to check the DC Jack. On a visual inspection I cannot see any obvious fault.
Without unsoldering and removing the jack what tests can I carry out to check whether or not it (the jack) is faulty? Is there anything against connecting the power adapter to the (removed) motherboard in order to check the output (if any) from the Jack?.
One way to check is to remove the battery from the notebook and connect the AC adapter to the notebook. If pressing the power button turns the notebook on, then you'll know that the jack is still good.
Does the jack/adaptor come with any sort of LED to show that power is being delivered? Or does the Laptop have such an LED? If no, then just get a multimeter to check whether the jack is delivering power. If not then replace the adaptor/cable else your mobo has some problems.
Thanks for your response.
There are two LED displays on the laptop, one of which should light up (even with the laptop switched off) when the when the AC Adapter is connected. The other should light up when the laptop is turned on. I have tried removing the battery, holding down the start button for 20/60 secs, leaving without battery or power for 24 hours and trying to restart with and without the battery. Neither LED lights up. No indication that the laptop is receiving power even with 19 volt measured at the input to the DC Jack. I also tried removing and reseating the RAM modules without success before deciding to remove the motherboard in order to examine the DC Jack. Having done that I cannot see any sign of corrosion or cold soldered joints on connections of the DC Jack to the motherboard. The DC Jack could have an internal fault stopping the flow of power through it. It occurs to me that a basic test of the Jacks functionality might be to measure its output but I am a little hesitant about applying power to the motherboard when removed from the laptop. My queries are:
1. Is it safe to feed 19 volts to the dc jack with the motherboard out of circuit ?
2. What tests can be carried out to check for faults in the DC Jack.(preferably while still in circuit)?
3. Does the fact that the battery will not recharge with or without the laptop switched on indicate a most likely cause of fault?
I connected the adapter to the DC Jack and switched it on. I could detect 19 volts (same as input voltage) on one of the jacks (output) pins soldered to the motherboard. The soldered joint appears to be sound, However, I cannot find any voltage at other parts of the motherboard which might indicate that the soldered joint is in fact defective. There is also no voltage on any of the seven pins on the battery connection and no voltage on any of the jacks pins other than the one. The DC Jack from input to ground has a resistance of 8K ohms.
This notebook died suddenly four month’s ago. I was convinced that the fault was with the mobo which would not be economical to repair so I purchased a new laptop replacement. I also purchased a HD enclosure which enabled be to retrieve files from the failed notebook’s hard disc. A few weeks ago I came across an article on the internet which said that if a laptop isn’t charging when plugged in it usually indicates a bad jack. Three scenarios were described.
(a) The DC Jack has cold soldered joints which is the most common
(b) The DC jack has been broken in hidden areas of the jack, a common diagnosis being the wiggling of the jack with the adapter
(c) There is nothing wrong with the DC Jack and it is an issue with something else onboard which is uncommon but can happen.
Armed with a circuit diagram, a multimeter and a dual trace oscilloscope (which I still have but not used for over twenty years) I used to be able to find & repair faults on the now obsolete valve TV sets of the 50s ,60 &70s, not as a business, purely as a hobby.. I never came to grips with modern digital electronics, micro chips and processors which were all far too complex for me to embrace and I was forced to give up my hobby. At 81 years of age I have no thoughts of taking it up again. However, having taken this notebook apart I will probably resolder the DC Jack before reassembling it. If the fault remains I will dispose of the notebook as I had originally intended to do. First I want to try and find out if there should be an output on more than one pin on the DC Jack. Also on the underside of the motherboard directly beneath the jack there are three small components about 2 mm in length which could be surface mounted devices not connected to the Jack If so I would not want to disturb these when unsoldering the jack. So I have a little more research to carry out