The Posistor


The posistor which is also called Posistive Coefficient Thermistor(PTC) is an electronics device common in almost all television circuit.At room temperature(25'C) it has a low resistance but the resistance becomes high when current flows through it.The posistor works in conjunction with the degaussing coil to give a balance colour on the screen.
whenever there is colour patches on screen,this is a sign of defective posistor.A short in degaussing coil can also result to a dead circuit.

faults related to memory ic in television

There is this television brought to me over the weekend-a medion 14'' Tv-when you power it the standby light is on but it fails to start.Checking the power circuit the components are fine from my meter readings though,less emphasis should be placed on the power circuit for this type of fault.The main focus should be on the reset circuit and the secondary side of the SM transformer.Let me state here that you need to master how to take voltage readings(most especially dc volts) with your reading meter because this fault requires tracing dc volts to correct it.I took my dc volts reading at horizontal output and it gave me 110v which is okay .Same apply to all the volt supply from the secondary side of the switch mode transformer,that is the 25v,16v........and since the readings from the reset circuit tells me the components that constitute it are fine, the next suspect is the memory ic and it is always located near the microprocessor(system ic).This tv has a 24C08 ic.and immediately I changed it and powers the tv,it came on and was working perfectly.