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Author Topic: how do I test electronic components?  (Read 6263 times)

Offline Seeker-Ian

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how do I test electronic components?
« on: October 05, 2004, 03:57:12 pm »
Ok stupid questions. if this should be moved to kletts forum, move it.

I was told to...  
Quote:


"Junction test the transiters"



how do i do this? just see if it measures voltage on my multi-meter?

Quote:


"Just ohm the burnt resistors, and replace".



how do I "ohm" them?

Quote:


"Junction test the transistors and replace the bad one(s) or shotgun all of them".



shotgun means to replace em all without testing? and again.. junction test?

Quote:


"Check the i/o caps, or shotgun them".



i assume he means to check for leaking caps. how would i check and verify before and after voltages?

Quote:


"Put an AC voltmeter on pins 1 and 7 of the op amps and see if you have signal. If you do, look at both sides of the output caps. Compare left channel w/ right to see what's supposed to be there."



I think i can do this.


Offline djui5

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Re: how do I test electronic components?
« Reply #1 on: October 05, 2004, 06:26:48 pm »
damm techies..


the only one I know is the "ohm test"....just see what kinda resistance (ohms) you get from the resistors..and if it's incorrect then you need to replace them....
Morale of the day? Stop looking at what you're hearing.
yngve hoeyland 07'

Randy Wright
Mix Engineer
Mesa, Arizona

Offline Seeker-Ian

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Re: how do I test electronic components?
« Reply #2 on: October 05, 2004, 06:37:49 pm »
so... send some voltage through the resisters, check the printed value of the resisters, then do the math?

I need a good web site for learning and applying this stuff.

I feel like such an idiot for not knowing this basic stuff.

Offline craig boychuk

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Re: how do I test electronic components?
« Reply #3 on: October 05, 2004, 06:46:52 pm »
You can find a simple color code chart here

http://xtronics.com/kits/rcode.htm


I'll bet if you google some of the topics you're looking for, you will come up with some good info...

-Craig
Capture the pasture rapture.
www.cbaudio.com

Offline Sahib

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Re: how do I test electronic components?
« Reply #4 on: October 06, 2004, 05:57:46 pm »
CKerian,

I hope you will not be offended by this but this is not the forum that you should be writing with this sort of problems.

I am sure some people wished to say this but I am prepared to be the bady in this instance.

Regards,
Cemal Ozturk


Offline trexrox

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Re: how do I test electronic components?
« Reply #5 on: October 07, 2004, 02:51:01 am »
Sahib wrote on Wed, 06 October 2004 17:57

CKerian,

I hope you will not be offended by this but this is not the forum that you should be writing with this sort of problems.


I don't see why not... This should fit right in with the purpose of this forum.  While the topic may be a bit elementary to an experienced tech, it's not for someone who is just starting out... and that seems to be what this forum is about: demistifying the technical aspects of audio gear.  And part of that is understanding components and how to test/ diagnose them.

Sorry, I don't have anything else to add at the time, but I just wanted to say that I'm in favor of allowing posts such as these to help out some up-and-coming techs as well as the more intensive posts for the well-rounded solder heads.

Offline Sahib

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Re: how do I test electronic components?
« Reply #6 on: October 07, 2004, 04:54:39 am »
This topic was already posted at Mixerman forum and I also thought that due to the level of the subjects discussed and the calibre of individuals ( myself excluded ) involved it was a bit out of place. However, this is by no means snobbing it as my brother ( Barish ) already replied to it in detail with even resistor codes in Mixerman's forum.
Finally,  I did not speak out for anybody else and it was purely my own view. I did not mean to offend anybody and I will terminate this discussion with this post.

Regards,
Cemal Ozturk

Offline Seeker-Ian

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Re: how do I test electronic components?
« Reply #7 on: October 07, 2004, 11:00:22 am »
hey Shaib. it's cool. I wasnt really sure.

and thank you Will, well said IMHO.

In hindsight, I think it is the wrong forum. i saw the title "theory to practice" and thought.. cool a electrical forum for maybe beginners or something.

dont we always bitch that most AE's dont know enough about the electrical engineering aspect of recording?

I knew it was the wrong place as soon as I noticed a lack of interest.

it's all cool. Issue resolved.

junction test failed on a transister.



Offline crazydoc

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Re: how do I test electronic components?
« Reply #8 on: October 07, 2004, 12:02:26 pm »
danlavry wrote on Fri, 01 October 2004 20:40

This forum is about the why and how of audio technology. It is about the electronic and electromechanical bridge between musician and listener.

....The goal of this forum is to improve our technical understanding, which also helps achieve better end results.


...The majority of "ear types" are not well equipped with science, engineering and math which are the foundations of audio technology. The majority of "technical types" lack studio experience. The challenge here is to communicate with people with wide range of interests and experiences. That and being objective requires care and cooperation from all participants.


I think this type of question fits in with the goals of this forum. There is a wide disparity of knowledge here, both technical and recording-wise, and threads that start at the beginning, or are elementary, I would think have a place here, if only to post links to other fora or sites where the subject is well covered.

Peter Wilcox

Offline Sahib

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Re: how do I test electronic components?
« Reply #9 on: October 07, 2004, 01:42:54 pm »
CKerian wrote on Thu, 07 October 2004 16:00

hey Shaib. it's cool. I wasnt really sure.

and thank you Will, well said IMHO.

In hindsight, I think it is the wrong forum. i saw the title "theory to practice" and thought.. cool a electrical forum for maybe beginners or something.

dont we always bitch that most AE's dont know enough about the electrical engineering aspect of recording?

I knew it was the wrong place as soon as I noticed a lack of interest.

it's all cool. Issue resolved.

junction test failed on a transister.





I'm cool too cKerian. Barish was asking me about your  transistor and last time I passed by him he was deep into his instructions to you. I hope you fix the problem and I would like to congratulate you for taking on a problem like that. It seems like you are doing all the right things.

Regards,







Offline Rail Jon Rogut

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Re: how do I test electronic components?
« Reply #10 on: October 07, 2004, 06:16:19 pm »
Found this link: http://www.allaboutcircuits.com/vol_3/chpt_4/3.html

Which may help you.

Rail
Recording Engineer

www.platinumsamples.com

Engineered Drums for BFD & Superior Drummer 2.0

Offline crazydoc

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Re: how do I test electronic components?
« Reply #11 on: October 07, 2004, 07:55:07 pm »
Here's a meta thread from The Lab, a site where meta-info can be found about all things audio-electronic, and if you can't find it, just ask.
http://www.prodigy-pro.com/forum/viewtopic.php?t=349

Peter Wilcox

Offline Seeker-Ian

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Re: how do I test electronic components?
« Reply #12 on: October 08, 2004, 12:49:22 am »
Thanks for those links everyone. I am getting pretty heavy into this thanks to everyone so i will be checking those links for sure. I just ordered my first $100.00 worth of soldering tools, transisters, and switches. resisters and caps to come once I figurte out those exact values I need.

it's already becoming like multiple trips to the hardware store and I already need more stuff

keep those links coming and maybe the available options for learning.

technical, vocational, internet, DIY?

Sahib wrote on Thu, 07 October 2004 02:54

my brother ( Barish ) already replied to it.

Regards,
Cemal Ozturk


Special thanks to you and your brother Cemal!!!! I must have missed this post. I will definately keep you guys updated.

I actually posted here first but got stupidly impatient. haha. poor me.










Offline Brian Roth

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Re: how do I test electronic components?
« Reply #13 on: October 08, 2004, 02:01:20 am »
A transistor is a "3-legged" device.  Using an ohm meter, you can check for "gross" failures.  From the base to emitter you should see a diode (relatively low resistance with the meter's leads connected one direction, very high resistance with the meter's leads flipped).  Same with the base to collector junction.  Collector to emitter should be high R with test leads in either configuration.  Experiment with a "known good" transistor to get the "feel" of how your meter responds.  Also keep in mind that "in circuit" tests like these may yield bogus results.

To "ohm" a given resistor, set your meter on the "ohms" scale and read the resistance, then compare it to the value marked on the part or in the schematic.  Again, "in circuit" numbers may be waaay off the mark.

"Shotgun" means to replace any/all suspect parts.

Testing caps requires that your metering gear can read capacitance values, and again, you might come up with bogus values while testing the parts in-circuit.

Bri

Brian Roth Technical Services
Oklahoma City, OK
www.BrianRoth.com

Offline Seeker-Ian

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Re: how do I test electronic components?
« Reply #14 on: October 08, 2004, 05:01:12 pm »
Thanks Brian. all these lessons and posts are giving me a hell of a lesson.

thanks again everyone!! keep em coming.

Offline Geoff_T

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Re: how do I test electronic components?
« Reply #15 on: October 10, 2004, 01:58:00 pm »
Hi

I just thought I'd chime in with a couple of pointers...

1. You can test transistors and diodes with the multimeter set to the "diode symbol" (rather than ohms). If you, for instance, put one probe on the centre wire of a transistor, you should get either infinity or around 600mV if you touch the other probe on either of the two outer legs. If you reverse the leads you will find that the readings reverse... or should do.

2. The problem with checking resistor values directly on a pcb is that other resistors might be in parallel with it (like the base bias resistors on a transistor via the power supply) and, if the resistor is not close to the colour band value, it's a good idea to unsolder one leg of the resistor and pull it out of the pcb. Then check the resistance value again and external influences will have been removed.

Smile
Geoff Tanner
http://www.auroraaudio.net/main.shtml
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NB Please do not pm me if you want a fast response... please email me.

Offline Brian Roth

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Re: how do I test electronic components?
« Reply #16 on: October 11, 2004, 12:55:29 am »
Hi, Geoff!  I thought I'd add to your comments.  Many plastic transistors follow the "emitter-base-collector" wire lead sequence, but not all do.  Some have the base at one end or the other instead of the middle lead.  Those tend to me transistors from Europe or Asia vs. the USA.

For checking transistors, I've kept an ancient, beat-to-hell analog VOM in my tool kit.  I've used it enough to have a "feel" of how a transistor should "look" on the meter.  I guess I'm a Luddite since I've had variable luck using a digital meter to check transistors in-circuit.

I'm glad you also reiterated the possibility of "bogus" readings with a component still soldered into the cirsuit.

Bri



Brian Roth Technical Services
Oklahoma City, OK
www.BrianRoth.com

Offline Barish

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Re: how do I test electronic components?
« Reply #17 on: October 11, 2004, 10:17:53 am »
For those who feel themselves too lazy to be bothered with good old fashion way of testing transistors, there is a doc's pager sized mini test device called Atlas DCA-55 Semiconductor Component Analyser from a UK company called Peak Electronics. It costs
M Ozturk

Offline Geoff_T

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Re: how do I test electronic components?
« Reply #18 on: October 11, 2004, 12:14:17 pm »
Hi

When I want to test transistors seriously (rather than just see if the junctions still function) I use an old Heathkit tester that you can buy off eBay for peanuts. It has a great big, easy to read, meter and comes in a neat carry case.

Like this one....

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1 504&item=3845417150&rd=1

Smile
Geoff Tanner
http://www.auroraaudio.net/main.shtml
http://www.grandmasterrecorders.com
    http://www.amazon.com/gp/reader/0595093329/ref=sib_dp_pt/104 -6861899-0350336#reader-link

NB Please do not pm me if you want a fast response... please email me.

Offline Sahib

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Re: how do I test electronic components?
« Reply #19 on: October 12, 2004, 06:00:22 pm »
Barish wrote on Mon, 11 October 2004 15:17

For those who feel themself too lazy to be bothered with good old fashion way of testing transistors, there is a doc's pager sized mini test device called Atlas DCA-55 Semiconductor Component Analyser from a UK company called Peak Electronics. It costs

Offline bobkatz

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Re: how do I test electronic components?
« Reply #20 on: October 12, 2004, 06:08:02 pm »
I like that Atlas box you describe, Barish! Saves a lot of time and trouble!


Wonder how it will do with a transistor that's in circuit...

BK
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One says-this is old and therefore good.
The other says-this is new and therefore better."

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Offline Seeker-Ian

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Re: how do I test electronic components?
« Reply #21 on: October 13, 2004, 12:01:59 pm »
Thanks for the link Geoff. i am currently the top bidder of that heath kit tester.

BTW Bob.. i enjoyed your book. very nice and worth every penny.

an update on my problem... I replaced the transisters for this section of my mix bus and it returned my volume on the right mix bus but.. the distortion is still there. getting closer. next step is the caps though they all look new.

ideas?





Offline Sahib

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Re: how do I test electronic components?
« Reply #22 on: October 13, 2004, 02:48:47 pm »
bobkatz wrote on Tue, 12 October 2004 23:08

I like that Atlas box you describe, Barish! Saves a lot of time and trouble!


Wonder how it will do with a transistor that's in circuit...

BK


Bob,

Unfortunately it does not measure on the circuit. But it is still a great device. There is another version available from the same company which tests LCR.

Cemal

Offline Barish

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Re: how do I test electronic components?
« Reply #23 on: October 13, 2004, 06:36:06 pm »
bobkatz wrote on Tue, 12 October 2004 23:08

I like that Atlas box you describe, Barish! Saves a lot of time and trouble!


Wonder how it will do with a transistor that's in circuit...

BK


Hi Bob,

As Sahib and the user manual of Atlas said, "it is designed to test discrete, unconnected, unpowered semiconductor components". An FAQ document is available on the product page on their website (or alternatively here).

I'm not aware of a tester that is capable of measuring components connected on the board without getting confused by the rest of the circuit.

Regards,

Mahcem
M Ozturk

Offline OOF!

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Re: how do I test electronic components?
« Reply #24 on: October 13, 2004, 07:02:05 pm »
hey ck,
this is the perfect forum for this question.  i've learned so much from these guys.
additionally, everything you need to know can be found on the web.  search under various words and you'll get all the instruction you need.  i couldn't believe all the useful info i got and it put me on the way to learning this stuff.  here are a few of the more useful links i found.

http://www.doctronics.co.uk/scope.html
http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/oscillo scope.html
http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/termino logy.html
http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/setting .html
http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/control s.html
http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/meastec h.html

also, get yourself a tektronics scope on ebay. they're invaluable- around 250 bucks.
good luck,
david lawrence

OOF!