Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Equipment Usage, Soldering, Techniques, and Reviews
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 10-02-2018, 04:54 AM   #1
techi
New Member
 
Join Date: Oct 2018
City & State: Gothenburg
My Country: Sweden
I'm a: Knowledge Seeker
Posts: 6
Default What are the minimal devices needed to do the most usual electronic repairs?

I have the basic stuff needed for soldering including a hot-air rework station and a multimeter.
So I'm wondering if this is enough to do most electronic repair work or do I need more
advanced(expensive) devices such as an oscilloscope to repair usual stuff such as phones,
speakers, radios etc. Isn't it possible to debug most things using only a multimeter?
and if not, then what things would I be able to debug and fix with only a multimeter?
All your answers would be really appreciated!
techi is offline   Reply With Quote
Old 10-02-2018, 11:49 AM   #2
Curious.George
Badcaps Veteran
 
Join Date: Nov 2011
Posts: 807
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by techi View Post
I have the basic stuff needed for soldering including a hot-air rework station and a multimeter.
So I'm wondering if this is enough to do most electronic repair work or do I need more
advanced(expensive) devices such as an oscilloscope to repair usual stuff such as phones,
speakers, radios etc. Isn't it possible to debug most things using only a multimeter?
and if not, then what things would I be able to debug and fix with only a multimeter?
All your answers would be really appreciated!
It's not a question of what you need as much as how effective you want to be in your efforts. And, how much information (schematics, advice, reports from others who've tackled similar problems, etc.) you have to assist you -- as well as your own level of experience and understanding of the common circuit topologies you'll encounter.

Personally, I don't want to spend a lot of effort trying to guess at what's going on in a circuit (without documentation). So, having a DSO, logic analyzer, etc. cuts my debug time considerably.
Curious.George is offline   Reply With Quote
Old 10-02-2018, 12:15 PM   #3
Andrew F. Ali
Badcaps Veteran
 
Andrew F. Ali's Avatar
 
Join Date: Jan 2014
City & State: Point Fortin
My Country: Trinidad & Tobago
Line Voltage: 125VAC 60Hz
I'm a: Knowledge Seeker
Posts: 2,165
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Exactly!!! Having the tools and not knowing how to use them and without documentation, schematics, etc, in addition no knowledge of electronic/electrical basic principles and no knowledge on testing electronic components would definitely affect one's effectiveness as an Electronic Technician/Engineer.
Andrew F. Ali is offline   Reply With Quote
Old 10-02-2018, 01:28 PM   #4
techi
New Member
 
Join Date: Oct 2018
City & State: Gothenburg
My Country: Sweden
I'm a: Knowledge Seeker
Posts: 6
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Thanks for not answering my questions!
I have repaired my phone by changing it's charging port when it didn't want to charge.
I concluded that it probably was the charging port that was at fault after I charged
the battery by other means and the phone worked as usual and I found the only problem with it was when trying to charge it through the charging port.
This I solved without even a multimeter, and changing charging ports - as of what I have read - is the most common phone repair work.
So my question is: Is there much more "common" repair work I can do as a beginner with a multimeter as my most advanced tool, and what could those repairs be?
And to @Andrew F. Ali, Why do you presume that I have NO knowledge about basic elecricity/electronics and doesn't even know how to use my tools?
Seriously... where did you get that from?
And if by "no knowledge of electronic/electrical basic principles" you meant that I have no electronics engineering degree, then yes that's true.
But I supposed that knowing about voltage, current, resistance, how they relate to each other,
how to build basic circuits with basic components(resistors, capacitors, switches, potentiometers, etc) would be enough to at least begin trying to repair easier things.

Last edited by techi; 10-02-2018 at 01:47 PM..
techi is offline   Reply With Quote
Old 10-02-2018, 04:09 PM   #5
Andrew F. Ali
Badcaps Veteran
 
Andrew F. Ali's Avatar
 
Join Date: Jan 2014
City & State: Point Fortin
My Country: Trinidad & Tobago
Line Voltage: 125VAC 60Hz
I'm a: Knowledge Seeker
Posts: 2,165
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

My post wasn't meant to embarrass you. I apologize for this. What I was trying to determine is do you know how to test components. Anybody can measure continuity and with basic knowledge unsolder, remove, replace and re-solder a part. But the question is how does one determine if a component is doing what it is supposed to do and how efficient is it? I was where you are at one time, a very long time ago in the 1960's. When I started to learn electronics there was Thermionic valves and capacitors were called condensers. So again, please accept my humble apology I definitely was not trying to humiliate you.
Andrew F. Ali is offline   Reply With Quote
Old 10-02-2018, 04:52 PM   #6
petehall347
Badcaps Veteran
 
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 1,383
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

most usual electronic repairs covers a lot . i just get by for a one off but if i need a new tool for sure i will get it .
petehall347 is offline   Reply With Quote
Old 10-02-2018, 05:16 PM   #7
techi
New Member
 
Join Date: Oct 2018
City & State: Gothenburg
My Country: Sweden
I'm a: Knowledge Seeker
Posts: 6
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

@Andrew F. Ali
Thank you, your apology is accepted.
techi is offline   Reply With Quote
Old 10-02-2018, 05:43 PM   #8
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 2,800
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

I use a scope (with isolation transformer) all the time, Checking the ripple on caps, checking smps drive signals, checking audio/video signals etc. Often people don't know if the lack of video on a lcd for example is caused by the main board, t-con or panel, but scoping the lvds signals and the drive to the panel takes 2 min of time and you know where the problem is.
A lot can be done with a meter but sometimes other equipment can speed the repairs.
R_J is offline   Reply With Quote
Old 10-02-2018, 06:25 PM   #9
petehall347
Badcaps Veteran
 
Join Date: Jan 2015
City & State: worcester
My Country: United Kingdom
I'm a: Knowledge Seeker
Posts: 1,383
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

it is what works for you .
petehall347 is offline   Reply With Quote
Old 10-02-2018, 06:35 PM   #10
Curious.George
Badcaps Veteran
 
Join Date: Nov 2011
Posts: 807
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by techi View Post
Thanks for not answering my questions!
I have repaired my phone by changing it's charging port when it didn't want to charge.
I concluded that it probably was the charging port that was at fault after I charged
the battery by other means and the phone worked as usual and I found the only problem with it was when trying to charge it through the charging port.
This I solved without even a multimeter, and changing charging ports - as of what I have read - is the most common phone repair work.
Now, ask yourself what you would have done had it NOT solved your problem?! Would you even know where to go probing the circuit for failure symptoms? If you had a 2GS/s DSO, would you even know what to look for? Or, how to recognize if what you were seeing was "correct" vs. faulty?

If all you want to do is fix phones that don't charge, don't even waste money on a DMM; just replace the charging port on any phones that don't charge! If it then works, you've got another success! If it doesn't you're at a loss to go any farther, right?

Quote:
So my question is: Is there much more "common" repair work I can do as a beginner with a multimeter as my most advanced tool, and what could those repairs be?
How much time do you want to spend and how many successes do you want to have? How many charging ports do you want to replace and then discard the phone (or whatever) when the problem doesn't go away?

EXPERIENCE (with specific types of devices and circuit topologies) will usually tell you more than the DMM. The DMM will just be a crude tool to verify what you've already suspected (e.g., "charging port not functioning")

In the early 80's, pinball machines were just "going digital". My future F-in-L ran a vending route. He had just purchased "one of those new-fangled things" and it wasn't working -- out of the box! He asked me to look at it.

With no tools on hand (I was thousands of miles from home), I was able to diagnose the problem and fix it (by buying a soldering iron at the local Rat Shack). But, that was only because I knew what was going on inside the hardware/software and could use my eyes and brain to sort out the likely cause of the failure!

A DMM wouldn't have helped. A 'scope might have. But, the real "tool" was the wetware between my ears! Knowing what I could look for -- without any tools -- and then drawing conclusions based on those observations and my knowledge of how they reflected the actual circuit.
Curious.George is offline   Reply With Quote
Old 10-03-2018, 02:46 AM   #11
techi
New Member
 
Join Date: Oct 2018
City & State: Gothenburg
My Country: Sweden
I'm a: Knowledge Seeker
Posts: 6
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Thanks for your answers.
What I have understood from your answers is that an oscilloscope is not really
necessary at this stage. I should focus on analysing and troubleshooting circuits and studying
to improve in fixing things and I will know if I need a scope when the time comes.
techi is offline   Reply With Quote
Old 10-03-2018, 04:24 AM   #12
Curious.George
Badcaps Veteran
 
Join Date: Nov 2011
Posts: 807
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by techi View Post
Thanks for your answers.
What I have understood from your answers is that an oscilloscope is not really
necessary at this stage. I should focus on analysing and troubleshooting circuits and studying
to improve in fixing things and I will know if I need a scope when the time comes.
An oscilloscope is a DMM that shows changes over time. This can be very important for AC signals -- almost useless for DC! If you KNOW the nature of the AC signal that you are measuring, a DMM can give you comparable SUMMARy data to what you'd get from a scope (e.g., the AC mains are ~160 but appear as "120VAC" on a DMM -- they'd appear as 160V on a 'scope but you'd know they are "120VAC")

OTOH, if you're looking at the output of a UPS and wondering why it's not behaving as you'd expect, you'd want to know what the REAL waveform looks like -- because you KNOW it isn't the "AC Mains".

"Tinker". Get a feel for the types of things that go wrong with various devices, even if you don't know what's ACTUALLY "broken". Put anything that may have value aside (don't risk damaging it before you know what you should be doing).

Eventually, you'll develop EXPERIENCE... you'll know to look for X when faced with a broken Y.

Growing up, if your car didn't turn over, it was either battery or alternator (failing to keep the battery charged). Battery is easier to test so you'd try that, first.

OTOH, I had a vehicle that ate alternators. I soon learned that the diode trio would fail making the alternator useless. And, rather than replacing the entire alternator each time, I got in the habit of just replacing the diode trio (requires disassembling the alternator). So, whenever it failed to start, I'd immediately pull the alternator and remove the diode trio -- KNOWING (from experience) that the repaired alternator would bring the battery back to life.

Fast forward to "now" and I don't do ANY testing when the car fails to turn over. I know the battery is shot because our heat cooks batteries in just a few years -- why bother testing it?

In each of these cases, I could burn myself by jumping to conclusions. But, that would be the exception rather than the rule. And, I don't need any fancy test equipment to make these diagnoses!
Curious.George is offline   Reply With Quote
Old 10-03-2018, 08:54 AM   #13
Andrew F. Ali
Badcaps Veteran
 
Andrew F. Ali's Avatar
 
Join Date: Jan 2014
City & State: Point Fortin
My Country: Trinidad & Tobago
Line Voltage: 125VAC 60Hz
I'm a: Knowledge Seeker
Posts: 2,165
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by techi View Post
@andrew f. Ali
thank you, your apology is accepted.
Andrew F. Ali is offline   Reply With Quote
Old 10-03-2018, 09:46 AM   #14
budm
Badcaps Veteran
 
budm's Avatar
 
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 33,890
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by techi View Post
Thanks for your answers.
What I have understood from your answers is that an oscilloscope is not really
necessary at this stage. I should focus on analysing and troubleshooting circuits and studying
to improve in fixing things and I will know if I need a scope when the time comes
.
That will be a real good start.
__________________
Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956

Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999

Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/

TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
budm is offline   Reply With Quote
Old 10-03-2018, 11:35 AM   #15
llonen
Badcaps Veteran
 
Join Date: Sep 2014
City & State: united kingdom
My Country: hampshire
Line Voltage: 240 VAC 50Hz / 110 VAC 50 Hz and 415 VAC 50Hz
I'm a: Professional Tech
Posts: 267
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

I have been running a repair service successfully for quite some years now, my work day can be anything from tumble dryers / washing machines to macbook pro's and lots in between I do avoid mobile phones except for data recovery work though. In addition household and commercial installation work makes up some of my workload.

In no particular order then, don't overlook the importance of a good solder extraction system, wick and solder suckers do not work well with modern through hole plated and high thermal mass rework. Other than that work through the online repair forums and resources it is highly likely that some one has already solved / reworked the problem facing you on your workbench, and just as importantly pass on what you have learned back to the communities and forums. These are also the places to ask questions, these sources can also be an invaluable source of service manuals and related information.

So what do I use,

I have a large investment in hand soldering systems and solder extraction tools, as well as hot air rework tools, along with solder fume extraction these I would not be without. microscope and way too many hand tools.

Test equip some of which that come to mind, kind of in order of usage

Digital meter(s) I prefer fluke
Analogue meter(s) I prefer Avo
Various Peak Atlas transistor / Esr testers
Oscilloscope(s) still looking for a decent digital one
Function generator(s)
RF signal generator
Modulation meter
Spectrum analyser
Audio signal gen
Logic analyser
Frequency counter(s) for some reason I seem to collect these
RF power meter
Through line attenuator (s)

Fluke multi test
Seaward Europa plus tester (s)
Mega DV4/Pat tester(s)

While I am sure this is not all of it, how much of it sees extensive use, I would say probably the test meters, and some of the RF test gear. followed by the electrical test gear at the bottom of the list. I have taken many years to amass this, but the majority of my work can and is done using only the test meters and information resources.
llonen is offline   Reply With Quote
Old 10-03-2018, 12:56 PM   #16
Curious.George
Badcaps Veteran
 
Join Date: Nov 2011
Posts: 807
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by llonen View Post
I have been running a repair service successfully for quite some years now, ...
I think "intent" colors your choice of tools. If the OP is just looking to "tinker", then he probably doesn't have much invested (beyond "pride") in any repair attempt. You, OTOH, have a commitment to the customer to, at least, "do no harm" (and an incentive to succeed and NOT have the item come back to you next week because you fell for the first failure before discovering its root cause!).

This is, IMO, important. It determines how much $$ you wish to throw at tools (unless money isn't something you have to worry about). And, how motivated you are to come up with the CORRECT fix, and not just "a" fix.

I spend most of my working hours in "design" so "repair" is more of a distraction -- a way to stop thinking about MY problems and, instead, address some OTHER problem. As a result, I don't get too invested in the kit that I repair. And, rarely take on a repair job for a friend/colleague as I want to be able to walk away from it as my schedule fills up (more important/fun things to do in life than fix other folks' problems!)

Quote:
Digital meter(s) I prefer fluke
I can almost live with a *2* digit DMM. I only use a meter to confirm what I already suspect in a circuit: "Is there about 1.8 volts, here?". I've long since tossed my HP3485 (8+ digit) as the bench space it required was ridiculous! I still keep a 6+ digit Fluke but its been so long since I've calibrated it that it's probably only good to 4!

Quote:
Various Peak Atlas transistor / Esr testers
I don't "test" components that I've removed from a circuit. I'm going to replace it -- which is why I've taken the time to remove it. If my diagnosis was faulty, I'll see little/no-change in symptoms.

Quote:
Oscilloscope(s) still looking for a decent digital one
Again, bench space hinders much of my 'scope usage. I have a modded TDS754D and TDS 540 DSO's as well as a sentimental Tek 465. When I'm using them (DSOs), the measurement capabilities are a real win! They are great for preparing tech manuals to support kit that I've designed (screen shots direct to files).

Quote:
Logic analyser
I have three (four?) LA's and they see even less use than the DSOs. Lots of bench space required. And, a PITA to hook up all the probes. I typically only use them when bringing up a new board -- and for documentation (as above). If you don't have documentation for the design that you're debugging, its hard to know what to probe (esp with so many SoC solutions out there!)

Quote:
While I am sure this is not all of it, how much of it sees extensive use, I would say probably the test meters, and some of the RF test gear. followed by the electrical test gear at the bottom of the list. I have taken many years to amass this, but the majority of my work can and is done using only the test meters and information resources.
I have an RLC bridge for those cases when I really need to understand why something (passive) isn't behaving as it should, on paper. And, a HiPot tester (primarily for UL certification).

As the sorts of tasks you need to perform change, so too do the tools you need to perform them! Each time you find yourself mumbling "Gee, I wish I had a...", make a note of it. If you find yourself mumbling that often, you know what to buy/acquire!

When I first started repairing pinball machines, a buddy ("old timer") carried nothing more than a 3ft length of wire (that looked like it was 50 years old with dried out/broken insulation, etc.). And, he always gave me one of those condescending grins when I dragged out my multimeter...
Curious.George is offline   Reply With Quote
Old 10-08-2018, 07:21 PM   #17
megaraider
Senior Member
 
Join Date: Jul 2015
City & State: Porto
My Country: Portugal
I'm a: Hobbyist Tech
Posts: 108
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by Curious.George View Post
An oscilloscope is a DMM that shows changes over time. This can be very important for AC signals -- almost useless for DC!
I agree with most you've stated,
but troubleshooting digital circuits (and most smps output voltages -"Badcaps") without an oscilloscope i would be f*
[but i might have misunderstood you or took it out of context]
megaraider is offline   Reply With Quote
Old 10-08-2018, 11:23 PM   #18
Curious.George
Badcaps Veteran
 
Join Date: Nov 2011
Posts: 807
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by megaraider View Post
I agree with most you've stated,
but troubleshooting digital circuits (and most smps output voltages -"Badcaps") without an oscilloscope i would be f*
[but i might have misunderstood you or took it out of context]
SMPS are largely cookie-cutter designs, nowadays. You may not know the switching frequency (without something that can SEE changes) or which output is being used to control the supply's servo -- but you know basically what's happening and where to go looking (for gross signs of failure).

Digital circuits are problematic if you don't have documentation (esp nowadays with the very high levels of integration in play). If you know (or can guess) the function of a particular signal, then a scope can give you an idea of whether it "looks like it might be working properly". Coming to a definitive conclusion, though, can be elusive.

E.g., if you KNOW this set of signals represents a data bus, how do you know the relative weightings of each (i.e., which "bit")? If you see activity on a signal, does that mean its the correct activity? Likewise, if you don't see any activity, is that a problem?

Many of the early microprocessors had multiplexed address/data buses. So, in a system with a lightly loaded bus, the "address" would "float" on the data pins (because those were also address pins, some epsilon earlier).

When bringing up i8085 hardware, if the board seemed to just "stop" -- before it even got started running your initial test software -- you would probe the A/D bus and see that the processor had stopped at location 0x0076. No coincidence that 0x76 was the opcode for the HALT instruction! (and 0x76 happened to have been placed on the A/D bus -- functioning in its ADDRESS role -- just a fraction of a microsecond earlier!)

Likewise, you can see processors that are stuck in continuous interrupts (cuz ISRs are typically very short so you see a tight, repeating pattern on each address or data line).

But, for any "sort of functioning" digital device, without documentation you're pretty screwed when it comes to sorting out what's going on "by observation".

[OTOH, if you are designing digital electronics, you can easily ensure that your design can be tested and debugged with just a "logic probe" (far less sophisticated than a voltmeter!)]

You pick your tools based on what you are likely to encounter in your efforts. I do a lot of digital design and its associated software/firmware -- along with comprehensive product/project documentation (user manuals, service manuals, manufacturing aids). So, I like having the ability to monitor 100+ signals (with a logic analyzer). Or, capture a transient "analog" event with a DSO. But, I can afford the effort of setting up the kit because it will be staying exactly where it is for a considerable length of time -- I'm not bouncing around to a variety of different signals as you'd typically do with a 'scope. (Do you really need to capture a 'scope trace if you're TROUBLESHOOTING a broken piece of kit?)
Curious.George is offline   Reply With Quote
Old 10-09-2018, 10:07 AM   #19
megaraider
Senior Member
 
Join Date: Jul 2015
City & State: Porto
My Country: Portugal
I'm a: Hobbyist Tech
Posts: 108
Default Re: What are the minimal devices needed to do the most usual electronic repairs?

Quote:
Originally Posted by Curious.George View Post
(...)
You pick your tools based on what you are likely to encounter in your efforts. (...)
Fully agree
megaraider is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2018
Powered by vBulletin ®
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 02:00 AM.

Did you find this forum helpful?