testing semi conductors

I'm new at this but I'm learning on my own so excuse all this threads. when testing semiconductors such as diodes and resistors can i test them on the circuit board itself with an accurate reading .also do u know of any sites that will teach me to read a circuit board with out schematics like i said this is new to me but i like it and I'm learning

Resistors are not semiconductors! But again you probably tought transistors which are semiconductors. As about testing it depends of components conected to the ones you are testing. Try serching trought this forum, I saw good discusion about it. Reading boards is a like reading schematics if you know how components look like and their values.

heyhi said:

when testing semiconductors such as diodes and resistors can i test them on the circuit board itself with an accurate reading .

Click to expand...

It doesn't give you accurate readings because your measuments are affected by the other components of the circuit board. Some diodes will give a reading of about 0.4 to 0.5 Volts on the diode test function, while still in circuit, which usually indicates that they are ok.

For most 2 wire devices ( diodes, resitors, capacitors ) lift one wire off the board for an accurate test.

Anything else it is better to remove the whole component to test it properly.

Hope it helps.

so when troubleshooting im suppose to take each component out n test it?

No; just the suspect ones.
Proper troubleshooting requires a service manual or a very good familiarity with the electronics used. Serviceable boards usually include test points and the Service manual will show you what to expect to measure at them, usually with an oscilloscope. The proper tools are a must if you want to get into the electronics service business.

PS your DVD player will use as many DVD related ICs as possible to keep the costs down, they are often very difficult to source and even harder to desolder & solder. Again special tools for this will all have to be part of your tool set.

The products i will eventually atempt to fix will not have a diagram.I'm just learning how resistors,capacitors,and diodes work.For instance I'm trying to fix my alarm clock because only half of each number displays.But with out a diagram i dont know where to start.I dont know the voltage after the transformer etc so testing it has me clustered.i ordered a 300 in 1 electronic lab project kit i hope that gets me on track. i have a begenirs book I'm reading but these books Ive looked at and websites all teach what parts do.and to check them disconnected i can find anything that will give me an idea at where to start troubleshooting. ..... The DVD player had some kind of loose connection.i took it apart fiddled around with it for a few days because i was getting familiar with the parts and testing, and it worked. i had it apart and i disconnected the DVD disc so the laser wasn't on and i plugged it in. i was tapping on the voltage board i was originally playing with and shaking it while plugged in and the lcd screen stayed on ...didnt flicker on and off like it was before..that was the only board i took off and it stayed on.the other board I'm guessing was audio n video i didn't touch that but i think something is loose on the voltage board..any way thank u guys..im really motivated to learn this stuff again I'm a beginner so ignore how neuritic i might sound .. if u wanna talk about commercial or ressidential electrica lI know what I'm talking about.Hopefully IL learn this soon

Your alarm clock probably has some bad contacts on display, this kinde of malfunctioning is very often with lcd display clocks. And bad conection is very common in all electronics so it is first thing I check.

Ah yes the Fonzi school of repair.
https://www.urbandictionary.com/define.php?term=Fonzie+it
**broken link removed**