Computer Repair Course Online. Lessons: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
Dell computers have their weak points.
Repair Dell Hard Drive. Dell desktop computers are built by the same principles as other desktop computers, and to repair them, you can use common tools which are widely available.
For example, a very frequent problem that occurs on dell computers is with the hard drive. The hard drive can fail on Dell computers just like on every other computer. The tools used for testing the hard drive on Dell computers is UBCD4WIN, HDTune, and GSmartControl. Dell desktops have a 3.5 inch hard drive which is either Samsung, Seagate, Toshiba, or another brand. Dell does not make hard disks. Hard drive diagnostics is described separately.
How to repair a Dell motherboard.
As mentioned already on this site, Dell desktop computers have the same problems as HP desktops involving capacitors.
On the motherboard, capacitors are located in different areas, but the main circuits are the same. Usually, they use typical schematics which have some additional components. What fails is usually the capacitors in power related circuits, for example, in the CPU step down voltage converter, the North Bridge power and the RAM power.
The good news about Dell computers is that they seem to use high quality aluminium case capacitors. Older Dell systems use the same capacitors as other branded computers and have the same problems relating to them.
For capacitor replacement, a powerful soldering iron can be used.
Small soldering irons such as the 35 W will not have enough power to heat up the solder. To start, heat up one pin and push the capacitor to the side and pull the pin out. Then, heat up another pin and push the capacitor to the side to pull the pin out. Repeat this until you can pull the capacitor out.
An easier way to do this is to use a de-soldering station or de-soldering gun like the Hakko 808.
Another common problem found on Dell computers is with the power supply. If the hard drive is found to be faulty or if the RAM is found faulty, always check the PSU first.
To test the PSU properly, simply using a PSU tester is not enough. It is better to use an oscilloscope. Connect the ground alligator to the chassis, and the probe to the +5 V on MOLEX. The voltage oscillogram shown must be clean and stable. Check the +12V on the same MOLEX. If it is shown clear and clean, then it is safe to replace the faulty part of the hard disk or RAM. If on the oscillogram has spikes or it fluctuates, then it is better to replace the PSU before replacing any other part.
Dell desktops do not often suffer from overheating problems. The only Dell desktop that I owned was the Dell GX280 which overheated when I watched videos.
Most overheating problems are with laptops. Laptops have a cooling system with fans and heatsinks. The heatsink is the cause of overheating. Because heatsinks are designed with very thin metal plates which are close to each other, dust cannot pass through the cooling system and dust particles will settle there. After a year of usage, the layer of dust can be substantial.
Memory fails can be common at times, but its rare and only happens on old systems.
It is possible to check the capacitors indirectly. Almost all the big capacity capacitors work in filters. Connect the oscilloscope probe to the capacitor + pn and observe the oscillogram. It should be stable and smooth.
If you do the repair, then you will most likely need to restore the operating system on the computer. A good way to do this is with the Dell operating system reinstallation disks shown below.
Computer Repair Lessons Continued: 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120
Me holding a laptop hard drive
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