Getting In Too Deep

TOSHIBA A75 series are workhorses they will run and run.  The only problems I have experienced with this model  that is fairly common is the DC Jack fails, Overheating and onboard memory failure. Since onboard memory can cause the above symptom, that was on of the first things I tested. The memory turns out to be fine. Opening the unit I see that there had been a previous spill that had dried and and was on some important VLSI chips. The next step was to closely inspect the spots where the spill was and visually determine if it could be the cause of failure.  This depends on whether it was on any PCI or video subsystems.  As it turns out it was on the PCI subsystem.

Some of the terms used by techs and myself: Dead: Means No Power, No Lights, No Charge Light.    Check DC Jack , test with known good battery No Power/No Lights: The unit will work from charged battery, but not from AC. Some light may be on.    Check DC Jack. When you move the charge plug with battery installed, the charge light may come on intermittently. This is caused by a cold solder joint on the DC Jack, or bad contact inside the jack.  No Power/With Lights: If you hold the plug at an angle, the unit will come on, but letting go of plug it shuts down.    Check DC Jack Will Not Charge Battery: Unit runs when plugged in, but will not charge battery. Or the battery only last 15min after charging all day.    Check Adapter - Generic or Wrong Amperag e Example -If you are using a 65w charger and trying to charge a DV9000 the battery will never fill up to it's maximum. Volts x Amps = Watts   18.5v x 3.47a = 64w ...

A few individuals have asked questions direct, and I wish to clarify some items.  It is best when you post on the blog that way it can also answer several hundred other readers questions. Question  1:  How do you check the (brown) ceramic caps. Answer:  Simple, I use a standard Ohm meter in the Resistance mode.  Since the biggest problems with caps when they fail is the become either a direct short, or they will never store capacitance (open).  The meter reads in the ohm mode by sending a small amount of electricity through resistors and report the difference in Ohms. Test with leads RED on one side and Black on the other.  One direction will give you a high resistance ~2000Ω and then reverse the leads on the meter and the other direction should give you Infinity. This is an OK capacitor. If you have a very low resistance or 0 (zero) Ohms, the cap is shorted. Why?:  I started small just repairing for friends and family, after a number of ...

Symptom 1:  Unit runs for a while then turns off Symptom 2:   Unit turns on, turns off immediately This unit arrives after another tech had attempted repairs.  Numerous screws missing from base and incorrect screws used in reassembly.  Complete tear-down and disassembly. After powering the unit up, I noticed that the heat sink copper was discolored [darkened] which is a sign of high heat.  Upon close inspection I noticed a kink in the heatshrink material covering the wires for the fan wires, so I strip back a portion of the insulation and the red wire was broken, and the black wire was only 2 strands. Yellow and White wires were OK.  Rather than replacing the fan (which is in short supply, and costly) I repaired the broken wires with solder and insulating them so that they would not short each other or the frame of the HS fan, which is negative ground. Screw also missing on the exterior frame that holds the heatsink downward onto the base, th...