global Laptop and motherboard repair tutorial | Page 82

magnifying glass that rests on your head and has multiple lenses to allow you greater magnification.
The headset also has built in adjustable LED lights. This will allow you to work with both hands free.
You will inspect all components for physical defects.
VOLTAGE REGULATOR
VRs will typically need to be tested with a multi-meter. To visually inspect the regulator, you
would be looking at the contact arms, mainly where they meet with the contact pads, looking for
melted solder as well. Usually board flex (heat contraction and expansion of the motherboard) will
cause the VRs arm to become mis-seated from the pad. When a Voltage Regulator fails due to a
power surge, it will have visible signs of failure. You will need to ―zoomǁ in to closely look at the
surface of the VR chip. You will see a burn area usually circle in shape and can sometimes be as
small as a pin-head or as large as the chip size itself. Certain blown VRs will still allow the laptop to
continue running, yet the blown VRs will also continue to ―shortǁ and if left unattended and
continuous power is applied, it can cause the surrounding area to burn and possibly set ablaze. If you
in fact do see visual damage, you will replace that voltage regulator from the motherboard. Usually it
will only be that 1 VR, and not the set (if in a set or series). First area to check is right near the DC
Input (whether the DC Jack Lands, or the Plug-In DC Jack Port) area, looking in the direct area and
also on the opposite side of the motherboard. The HP dv9000, dv6000 are 2 good examples that have
common failure to the Voltage Regulator chip located near its dc jack input plug port. This VR blows
quite easily and most likely due to poor/cheap manufacturing.
Grounding pin will usually be the last pin, schematics can help you on the pin count of needed,
and will tell you the last pins location and possible other grounding pins (so you don’t get false
readings). Once you place the multi-meters negative probe on the ground pin, you will go around the
arms starting from arm 1 and continuing around. To test for continuity, you would set the multi-meter
to beep or screech when positive power is detected.
To replace the faulty VR, you will need an exact replacement VR. You can’t just take one that
resembles the faulty one off of an alternate motherboard and expect it to work. It will most likely have
a different rating than the one at fault and can cause other nearby components to blow like oscillators
or caps. You can locate an exact series motherboard and remove the VR from it to use in replacement
of the faulty one. This might be your best option for replacing the component if you do not repair
laptops on a regular basis and have access to component inventory surplus. Looking up the part
number (zoom in on the IC surface to find it), then either Google it, or go on EBay to locate an exact
part match. If you get lucky you will find it, you just have to hope the seller/vendor allows the
purchase of a singular one and not require you to buy in Bulk (usually a case or 144).
CAPACITOR
The capacitor, or ceramic capacitor, or tantalum capacitor… will also be a component you want
to closely look at if you are looking to diagnose a Power failure like a lightning strike (my example)
and a Power surge or dip occurred. Visual inspection will reveal cracks in the capacitor or cracks in
the contact tray and pads. Electrolytic capacitors will test differently, as they will leak and will bulge
when failing. A useful tool for motherboard testing is a USB microscope. They are sold in various
strengths and even the cheapest – lowest strength scope will help greatly in seeing the components,
especially when you are able to view it on a monitor and save the captions to disk.
The way a capacitor should be tested is Out Of Circuit Testing, any component for that matter. In-
Circuit capacitor testing can be done using a Capacitance Meter, In Circuit ESR meter. OTHER
The power inductor and the power choke coil(s) can also be affected in a motherboard failure
issue. You will be able to feel the heat resonating from them usually after failure. Resettable fuses