What do I need?

[partyanimallighting]

I own a lighting company with a small rental inventory and, because of my location (3rd
world island in the Caribbean) I have no choice but to troubleshoot and attempt to repair
my inventory when a unit goes down. Most times I simply swap out defective PCB's or power
supplies with available replacement parts but sometimes I encounter older units that
require repairs and I have to delve deeper because replacement parts are unavailable.
Now, first and foremost, I am not a technician and I have never taken any sort of
electronics course, so my ability to read a schematic is vague to say the least but I
do recognize most component symbols. All that I have learnt, is from trial and error, information I've
found via Google and most importantly, assistance I've received from this forum. I am
getting deeper and deeper into repairs and was wondering what equipment I can add to my
minimalist work bench. At present I have a good multimeter, a few voltage transformers
outputting various AC and DC voltages (12 and 24) for testing, a variety of hand tools,
good lighting with magnification, an air compressor for dust and grime removal etc.,
just the basics. I also just purchased a rework station to work on SMD components and I'm
awaiting it's arrival. I have seen pictures of some workshops and some of them look like
something out of Star Trek, with scopes and testers everywhere and I don't think I will
ever need something quite this elaborate. Which brings me to my question...what should I
be looking at purchasing next? I know a scope is going to be suggested but I have no idea
how or what this would be used for and was wondering about the learnig curve also.

 

[Dimitri]

Learning curve takes time with an oscilloscope, because you sound like me when I started electronics beyond the standard "lab kits" my parents bought me in elementary school.

This is a fairly good guide.

https://learn.sparkfun.com/tutorials/how-to-use-an-oscilloscope

If you work with a lot of the same parts, which is what it sounds like. Take a good known part, and make a million notes of it. Something like this...

"Red output pin reads 12V peak to peak and it's 100ms in duration".

Once you work your way slowly from one side (say the power side) to the other (the output side), even without a lot of electronics knowledge, you'll be able to point to a bad part and say "Test Point 4, isn't correct and it's the output of the bridge rectifier, but the AC input is good".

Practice makes perfect, so don't beat yourself up over the learning curve of using a scope. It took me far too long to admit when I first really learnt to use one as a diagnostic tool.

 

[partyanimallighting]

You had "lab kits"??? What i do with all of my repairs is take a lot of pictures and make a lot of notes which are stored to PC under brand and model, so I can reference in the future. So far however, my memory's fine so, once I encounter a problem and resolve it, I rarely have to go back to my notes, it's embedded in memory. I am still no way proficient in repairs, but I have learnt so much here from you guys. I still haven't reached the stage of being able to read a schematic clearly, mainly because I can't source schematics for the majority of the units I dabble in and I think I really need to get a greater understanding of this in particular.

 

[kellys_eye]

You need knowledge.

Without an understanding of the basics of electronics you will be forever relying on others to do the job YOU want to do.

Spend your evenings reading the basics of electronics, fault finding and test equipment use. There are many, many good books available (and downloads) that will 'walk' you through all the processes.

I note your latest purchase is a solder rework station...... I've been repairing electronics for around FORTY YEARS and I still don't own or use one! Whilst appreciate modern electronics often require the use of such tools to replace parts, actually knowing WHICH parts to change is far more important - I then usually struggle with a magnifying glass (or CCD camera arrangement) and standard tools and tweezers to replace the part(s). If I was to work full time on such repairs then I'd probably get a rework station but your priorities seem to be skewed somewhat imho.

A decent test meter and a oscilloscope and you can find/fix 99% of all faults IF YOU KNOW THE BASICS of circuit operation. The less knowledge you have, the less chance you have of fixing it - obviously......

I still haven't reached the stage of being able to read a schematic clearly

makes part of my point succinctly. Basic principles lead to full understanding - I spend hours reading schematics for fun (Mrs k_e thinks I'm a nut job!).

It doesn't take long to get to grips and your understanding grows with each stage of learning - the best way to learn is to try to understand what you're doing such that you could confidently teach it to someone else - when you get to that point, consider the knowledge 'learned'.

 

[Dimitri]

See, your already well on your way, a scope is just another tool.

If your devices use PWM, AC to DC conversion etc, it will help you visualize your signals, instead of just a reading from a multimeter.

Honestly, I don't use my scope regularly, but sometimes, it becomes indispensable as it gives you the "ah huh!" moment, when a single signal is wacky.

 

[dorke]

One thing that will help you a lot is having the service manual of the equipment you are trying to repair.
It has the schematics and usually a troubleshooting guide,sometimes it also has detailed explanation of the circuits.
Some can be found freely on the WEB others need to be purchased.

When you say a "lighting company" do you mean LED lighting mostly?
What other types of lighting and equipment?

 

[turbogt16v]

If you dont start from the beginning, you will always run in circles.
Download electronic book for starters, and learn components that u use, its only 10 or 20,and then learn ac dc curent, buy solder station and go

 

[partyanimallighting]

Yes, mostly LED lighting, along with HID discharge lamp units and fog machines. My problem is that's it's a lot of Chinese product and, if I run into problems, the companies will simply send replacement parts which I swap out and for the most part they don't offer anything like a service manual or schematic. By simply swapping out parts I learn nothing about what caused the problem in the first place. Even the US based companies generally don't like to share service manuals.

 

[partyanimallighting]

If you dont start from the beginning, you will always run in circles.
Download electronic book for starters, and learn components that u use, its only 10 or 20,and then learn ac dc curent, buy solder station and go

Any links to downloadable books for starters that you would recommend? The solder rework station is on order and I'll receive that soon.

 

[kellys_eye]

The consumer electronics industry is plagued by two problems - one is IPR (intellectual property rights) where no one is prepared to tell anyone anything, or reveal any technical data they don't have (want) to.
Secondly (and it ties in with the first really) is their 'need' for built-in obsolescence. If the units are reliable they won't be selling many..... and if you can FIX them they can't sell you a new one so it's back to IPR..... catch-22.

Manufacturers would hate sites like this, where collective knowledge potentially prevents them making a sale but currently more people are happy purchasing replacements or the latest new models - i.e. have you seen the hype around the new iPhone and the morons queueing to buy them? - when, in reality, they offer little 'new' other than a label and a 'status'.... pathetic.

There is a (slow) growing realisation that new isn't necessarily better - and my own experience proved to me that older, proven and tested electronics stand the test of time, which is why the second-hand market in electronics is burgeoning.

I use printers that are 'industry quality' - not the domestic 'disposable' variety, second-hand tools frequently ignored by people just because of their age, not their quality/reliability - consumer goods with proven track records and a genuine spare-part system still in place etc etc. Test equipment is 'old' stuff with all manuals and technical descriptions written professionally and in great detail or stuff I make myself where the quality is as I see fit......

If you're serious about your business you need to start getting together the most reliable stuff - the stuff with spares availability, with schematics etc and KEEP IT. Service it as required - not just when it breaks down - and keep a proper record of everything about it. Past history details will pay off handsomely in time.

Build up a supply of spares yourself - spare boards, fuses, parts known to be stressed in use etc. If you have to replace parts use QUALITY replacements.

You only need to FIX equipment if you break it - do all you can to prevent that happening in the first place!

 

[dorke]

Yes, Chinese products are a big headache.

Poor design and quality,very bad reliability, false statements of specs.,false statements of safety regulations etc. etc. etc.

One other enormous problem that china is causing is breaking of patents and rights
,copying and forging almost everything.

Generally, Chinese products are cheap,and can be classified as one-time disposables

Worst of all,In my eyes, the fake industry of electronic parts in China is sacrilegious ...

That being said,there are exceptions:
I recently bought a Xiaomi Redmi note 4X at a fraction of the price of "the status label ones" ,
it is as good in every way...

 

[partyanimallighting]

kellys_eye, you are right. The price of replacement parts for some electronics is often as much as 75% of the cost of the unit. I have looked at some prices of parts for US branded lighting products and I have seen items like power supplies and replacement PCB's selling on these companies' parts pages selling for $115.00 and $200.00
respectively and these parts are available from Chinese companies (who supply the Chinese manufacturers) for $12.00 and $18.00.A totally ridiculous markup. But, given the choice, what would the consumer do? Purchase the part at the exorbitant price or buy the newer, updated, enhanced replacement upgraded model? And, as you said, new isn't necessarily better. As far as spare parts go, I do not ever purchase units from companies that do not offer a full warranty and, I only purchase product if additional spare parts are included in the order so I have a good selection of parts available at all times. I always request photos of internals, user manuals and schematics before I purchase. The photos and manuals are supplied without a problem. The schematics, never.
As far as servicing and repairs go, I service everything on a regular basis, notes and pictures are taken on all repairs for future reference and every piece of equipment I own is flight cased.

dorke, you are also so right but over the years, when I received a quality product from any company, I have continued to deal with these companies throughout. Cheaper is never, ever, better. But, as you also said, there are
exceptions.

 

[Alec_t]

One thing you need to be aware of when you have your shiny new oscilloscope: the 'ground' probe and the 'scope chassis are by default connected together and via the mains lead to mains ground. This can cause problems when you are trying to measure mains-related voltages in a DUT. The cure is to power the scope, or the DUT, via an isolating transformer. So add one of those to your shopping list.

 

[kellys_eye]

My in-laws wanted to fit those LED filament lamps all over their property and purchased all the lamps from a local supplier at some extortionate cost. I explained that I could get them direct from China for 1/5th the cost but they insisted that the local suppler, despite their high price, had a 1-for-1 warranty on them no-questions-asked kind of thing.

Well after a month or so they had failures into double digits! and I was't the least surprised that their supplier could offer their warranty given they probably got them from the same place I was going to!

And there by lies the rub - much of the stuff we see for sale on the high street actually CAN be purchased direct from China - it's no different! The high street mark up in sale price covers all the costs involved with shipping, handling, premises, staff and warranties so the price they sell for - whilst seemingly ridiculously high - has reason.

The claim of 'counterfeit' really only applies to named products - not the non-specific stuff, except where suppliers deliberately sell goods that have failed the OEM quality standard (and there's a lot of that around).

 

[AnalogKid]

Eventually you will have to have a scope, but there are many layers of scopes. To start out, especially if you have an old laptop you can dedicate to the workbench, consider a USB scope peripheral. They have enough voltage range and frequency bandwidth for the kind of troubleshooting you are doing, and are a good way to come up to speed at a relatively low cost. Plus, there is all of that image storage for your personal knowlegebase.

ak

 

[kellys_eye]

consider a USB scope peripheral.

Can't say I've ever seen one of decent enough spec to justify it's purchase over a 'real' 'scope. If all you want to scope are audio signals you could do that with a $15 Chinese scope kit!

 

[(*steve*)]

My problem with cheap USB scopes is that I can't be sure about isolation, so I'm putting my laptop at risk. Although I can run the laptop from batteries...

I have seen some really nice expensive USB scopes, but as mentioned, for the price you may as well buy a real scope.

I have my little battery powered oscilloscope that many decry as a toy. If I'm looking at low frequency signals it's fine, and I know it's completely isolated.

Having a scope show you a signal accurately and safely is one thing. Knowing what signal might be useful and understanding that signal are two other (and maybe bigger) issues.

If you're doing board swaps, keep the swapped out boards and see if you can figure out what went wrong.