Student electronics tech. question

[pfelectronicstechnician]

I'm a student Electronics technician at my local community college. I have lots of old home theater receivers and equipment that are obsolete. Home theater equipment gets obsolete pretty quick which is why I have so much old HT equipment. Do you think it would be a good idea to open up one of these old receivers and see all the parts inside as kinda a way to get hands on experience or just to get a good idea of what some electronics circuits really work? Any caution to doing this? Any testing I could do inside with my digital multimeter? Thanks for any help.

 

[4pyros]

You realy will not see much in those. It will most likely be a lot of surface mount components.
Maybe if one was made with through hole technology it would be worth opening.

 

[JimB]

I'm a student Electronics technician at my local community college. I have lots of old home theater receivers and equipment that are obsolete.

Do you think it would be a good idea to open up one of these old receivers and see all the parts inside as kinda a way to get hands on experience or just to get a good idea of what some electronics circuits really work?

Yes, I am surprised that you have not dived in there already!
I would have done in my earlier learning days.

Any caution to doing this?

What else are you going to do with the stuff? It is redundant and presumably cost you nothing, so if it is completely destroyed, what have you lost? Not much.
What have you gained? See my signature line.

One word on the safety front, beware of the mains voltages.
After you have opened the thing, and before you apply power, look to see where the mains wiring goes, see where it is connected.
Hopefully most live bits should be insulated, but just look to make sure before you poke around in there with power on, and keep your fingers away from the live bits.

Any testing I could do inside with my digital multimeter?

Try following the various supply lines around the circuit board from the power supply to the various (whatever is in there).

Try following the signal circuits.
Something like an oscilloscope would be useful here, but if you dont have such a thing, just follow the tracks to see the signal routing between various components would be useful.

Look at the numbers on the ICs, look for their datasheets on the internet.
Use the datasheet pin-out diagrams to assist in following the power and signal wiring on the board.

Surface mount components can be a bit of a pain, but they are the present and the future.
Go back 20, 30, 40, 50 years, all the old timers were lamenting these tiny transistors compared with valves, integrated circuits compared with discrete transistors, integrated circuits with more and more pins, surface mount compared with through hole components.
You just have to suck it up and get used to it!

Happy tinkering.

JimB

 

[pfelectronicstechnician]

Thank you very much for the help. Thank you JimB very much especially. Sounds like its a fantastic idea. These home theater receivers today are pretty complicated right, there is probably a ton of interesting stuff inside? The caution I was talking about was exactly what you addressed, power or shock potential. I have old DVD players too, but that I imagine can be VERY dangerous with the laser. That one I'd just open up to see what doing without powering up. Thanks again for the advice.

 

[Reloadron]

Do you think it would be a good idea to open up one of these old receivers and see all the parts inside

Figure it this way, it can't hurt even if you don't know what 90% of what you are looking at is. You may see patterns of sub circuits in there and hell a power supply should be easy to spot. I would go for it as nothing ventured and anything/everything to gain.

Ron

 

[Jugurtha]

Of course, man .. Here's something you can do:

-Fire-up a text editor.
-Open a device.
-Create a directory named "Datasheets" if you don't have one already.
-Look for ICs and their references, Google that up so you see what the chip does and figure out redundant blocks. Download the datasheets and put them in that category.
-Note each IC from the device in that text, with part number and what that chip does and possibly other devices you found it in.

Even if you don't remember everything, that's not the point. The point is to have exposure to things so it will hopefully be déjà vu when you need it.

For example, I was with my friends the other day and found a metallic box with an electronic board inside.. I picked it up, and took it home with me. I googled the stuff inside, and it turned out that box was an "ECU" from Bosch for automotive.. And it was responsible for controlling the Xenon headlights. (HID Ballast).

This brought me to digging up that stuff (ECUs/ECMs, etc...) I've learned that there are some people who "remap" memories to change the torque limit of an engine for example (think CAT, etc).. Learned about CAN bus, I²C, OBDII, RS485.. And it happens that I will need this stuff later, matter of fact.

All of this, because I picked up a metallic box from the ground.

 

[trash]

I'm with JimB on this too. Dive on in.
If you put your fingers in the wrong place, well you'll learn a lot quicker and your memory will be improved because you won't make the same mistake again.

 

[Rescue1]

Stick with the unplugged HT Receivers and stay away from older TV's as they like to store crazy amounts of voltages even when unplugged. Other than that I say go for it, that's how we all learn. Epically with the power supply parts as every project that your going to build or play around with will require one of these, and knowing how to troubleshoot and build them is important. Good luck either way..

 

[pfelectronicstechnician]

Let me ask you another question I have. When you graduate with an ET diploma and go and get your first job in the industry, what do employers expect? Meaning employers that higher a newly graduated ET, do they expect you to jump right in feet first or is it still a training process? Do a lot of employers like hiring "green" ET's that they then have to still give training to? I'm just a bit worried about an employer taking me on, not having any real world experience. Thanks for the help veteran ET's.

 

[JimB]

Everybody has to start somewhere, usually right at the bottom.

Any sensible employer should realise that you have a lot of theory but not much practical experience and make allowances for that.

Hopefully there would be someone with experience who can guide and advise you.

Here comes the problem, some of the established people may resent a newcomer and not be willing to give you information.
Or sometimes worse, only give you half the information.

An example from my own experience.
I had the opportunity to transfer from a department where I used my general electronic skill, to a department where I needed to know about computers.
This was back in the late 1970s when computers were much bigger and more fun than they are now with lots of lights and switches and componets you could see. And I knew nothing about them!
I had three mentors in my new department.
The main guy who was OK, but maybe a bit standoff-ish.
A guy who was a complete cynic and could not understand why I was there at all.
(The character Wally in the Dilbert series of cartoons reminds me of this guy!)
And a third guy, he did not work for that group any more, but sometimes came to stand in during holidays etc.
He was magic!!
He would explain stuff and put me in the right direction.
A great guy to work with.

Eventually it all worked out, I got to understand the stuff and was able to move to another site and develop my new found computer skills in more helpfull environment. Which was actually the company managements master plan in the first place.

So, you just have to get on with it, work out who to trust and who to beware of.

JimB

 

[pfelectronicstechnician]

JimB, you have set my mind at ease. I am learning an incredible amount of information, but not any in the field learning so I was worried employers would expect me to jump right in with both feet and just do it. Learning from veteran Techs is very desirable to me. I want to be a great ET, and learning from the veterans is the best way to do that. Thank you very much for the reply. Feel free to extend anymore info on this subject you think is relevant.