I want to repair a little pocket oscilloscope

Thread Starter

Loz2212

Joined Oct 9, 2018
28
Hi all,

I've been dipping in and out of electronics over the last few years but the relentlessly steep learning curve makes me lose interest and give up.

I'm currently in the middle of repairing a little pocket oscilloscope that I bought off eBay dirt cheap. I've repaired a burnt trace and replaced some components that I can see are visually damaged. Where would I even begin in understanding what is going on?

I'm envious of anyone who can open something up and see exactly what is going just by visually examining it.

My question is - how/where do you start in understanding about complex circuits? I'd also really benefit from some PCB architecture understanding.. etc.. some good sources would be very helpful. Happily pay for courses and/or materials.

Long term goal - I'd like to repair vehicle ECU's / Modules and get a good understanding of what I'm looking at.

I've attached a photo of the little oscilloscope I am looking at.

Thank you
 

Attachments

Delta prime

Joined Nov 15, 2019
425
I'm currently in the middle of repairing a little pocket oscilloscope that I bought off eBay dirt cheap
Hi there. If you purchased the unit recently.Stop your repairs your making it worse. Follow the steps .:) When you get a new DSO Nano, it’s suggested to inspect the product by the following steps:
1.Inspect for damage caused by shipping.
If the carton/plastic protection pad is seriously damaged, please keep the package until the product and
accessories pass the inspection electrically and mechanically.
2.Inspect the product
Please contact the company if the following problems occur: 1) product surface is damaged, 2) product
doesn’t work properly, 3) product does not pass performance test.
If the damage is resulted from shipping, please keep the package and contact the transportation department/
RIGOL distributor who is in charge of this service, for repair or exchange.
Make a quick functional inspection to ensure the product is working soundly. Please perform following steps:
1. Turn on the power supply, access homepage of the oscilloscope.
2. Connect the oscilloscope with standard signals (e.g. square wave 20KHz,Vpp=5V), set the switch on
probe tip as 1X, plug oscilloscope probe to the jack. Check whether the measured signal value is the same as the standard value; it can be calibrated if the
margin is small.
 

LesJones

Joined Jan 8, 2017
2,687
I would say that you need to understand how the device is designed to work. You would need a schematic of the device to do this unless it was a simple device that you already had a mental picture of the block diagram of the device. For example an audio amplifier which would take in a low level signal into the preamp stage then possibly through a tone control stage and then onto the power amplifier section. The software oscilloscope is a VERY complex device to start fault finding on. I think the only hope you would have would be if the fault was in the signal path between the input and the ADC input of the processor.

Les.
 

Thread Starter

Loz2212

Joined Oct 9, 2018
28
Hi there. If you purchased the unit recently.Stop your repairs your making it worse. Follow the steps .:) When you get a new DSO Nano, it’s suggested to inspect the product by the following steps:
1.Inspect for damage caused by shipping.
If the carton/plastic protection pad is seriously damaged, please keep the package until the product and
accessories pass the inspection electrically and mechanically.
2.Inspect the product
Please contact the company if the following problems occur: 1) product surface is damaged, 2) product
doesn’t work properly, 3) product does not pass performance test.
If the damage is resulted from shipping, please keep the package and contact the transportation department/
RIGOL distributor who is in charge of this service, for repair or exchange.
Make a quick functional inspection to ensure the product is working soundly. Please perform following steps:
1. Turn on the power supply, access homepage of the oscilloscope.
2. Connect the oscilloscope with standard signals (e.g. square wave 20KHz,Vpp=5V), set the switch on
probe tip as 1X, plug oscilloscope probe to the jack. Check whether the measured signal value is the same as the standard value; it can be calibrated if the
margin is small.
I purchased it as spares and repairs for £5. Worth having a go at that price.
 

Thread Starter

Loz2212

Joined Oct 9, 2018
28
I would say that you need to understand how the device is designed to work. You would need a schematic of the device to do this unless it was a simple device that you already had a mental picture of the block diagram of the device. For example an audio amplifier which would take in a low level signal into the preamp stage then possibly through a tone control stage and then onto the power amplifier section. The software oscilloscope is a VERY complex device to start fault finding on. I think the only hope you would have would be if the fault was in the signal path between the input and the ADC input of the processor.

Les.
Thanks Les - I'd be happy to learn on something a lot less sophisticated first and have a poke around.

Audio Amp might actually be the perfect thing to try.
 

BobaMosfet

Joined Jul 1, 2009
1,167
Hi all,

I've been dipping in and out of electronics over the last few years but the relentlessly steep learning curve makes me lose interest and give up.

I'm currently in the middle of repairing a little pocket oscilloscope that I bought off eBay dirt cheap. I've repaired a burnt trace and replaced some components that I can see are visually damaged. Where would I even begin in understanding what is going on?

I'm envious of anyone who can open something up and see exactly what is going just by visually examining it.

My question is - how/where do you start in understanding about complex circuits? I'd also really benefit from some PCB architecture understanding.. etc.. some good sources would be very helpful. Happily pay for courses and/or materials.

Long term goal - I'd like to repair vehicle ECU's / Modules and get a good understanding of what I'm looking at.

I've attached a photo of the little oscilloscope I am looking at.

Thank you
Title: Understanding Basic Electronics, 1st Ed.
Publisher: The American Radio Relay League
ISBN: 0-87259-398-3
 

Tonyr1084

Joined Sep 24, 2015
4,887
how/where do you start in understanding about complex circuits?
They say if you want to learn how to swim you jump into the deep end. Not so with electronics. The deep stuff is rooted in a firm understanding of the simple stuff. Fixing burnt traces and blown components is not as easy as it sounds. There can be many many more components that have been damaged but show no sign of such.

Start with the basics. Since I don't know how much you know I can't really make a good suggestion. I might be telling you to start at the beginning and learn to walk when you already know how to walk. Or I could suggest you try something that's above your current level of understanding.

AAC has a tutor course available for free. It's not the be-all, end-all of electronics but it's a good place to start. If you already have a firm understanding of resistors - then skip that part. Move at your own pace. You'll get there. But if you keep jumping into the deep end - you're going to get drowned out of the love of electronics.
 

dl324

Joined Mar 30, 2015
11,223
Long term goal - I'd like to repair vehicle ECU's / Modules and get a good understanding of what I'm looking at
While it's admirable that you have ambition, getting into ECU repair isn't something you can do without quite a bit of equipment and training/documentation from manufacturers.

It's a bread and butter business for auto manufacturers and they like that business to go to their dealerships. Dealerships don't try to repair modules; they just replace them because they're usually not worried how much money customers have to spend on repairs.
 

Deleted member 552872

Joined Dec 31, 1969
0
Hi all,

I've been dipping in and out of electronics over the last few years but the relentlessly steep learning curve makes me lose interest and give up.

I'm currently in the middle of repairing a little pocket oscilloscope that I bought off eBay dirt cheap. I've repaired a burnt trace and replaced some components that I can see are visually damaged. Where would I even begin in understanding what is going on?

I'm envious of anyone who can open something up and see exactly what is going just by visually examining it.

My question is - how/where do you start in understanding about complex circuits? I'd also really benefit from some PCB architecture understanding.. etc.. some good sources would be very helpful. Happily pay for courses and/or materials.

Long term goal - I'd like to repair vehicle ECU's / Modules and get a good understanding of what I'm looking at.

I've attached a photo of the little oscilloscope I am looking at.

Thank you
A troubleshooter's mentality is this: "my boss told me to fix it, and when I said 'I need a schematic', he said 'No you don't, now fix it"

I didn't believe it until I got in the field and started practicing my craft and witnessed time and again, a new-to-us piece of gear would show up, no schematic, no explanation of how it went together, and my peers on the job would attack it like hungry dogs and have it going in short order.

So I developed both hardware and software technique for this problem. The same thing pops up in software engineering - you often write lots of your own code so you know how that works, but it's part of a large software project and you have to learn the other parts you didn't write.
For electronic gear I did this:

1) what is the input and where is it connected on the board or piece of gear
2) what is the output and where is it located on the board or piece of gear
3) is a microprocessor on the piece of gear? Bam, get the model number off the chip, download its 'data sheet' from the internet

Once you do that, you start at the microprocessor and following the pins on that chip that provide the input. Do the same with the output pins. Every component along the way will have numbers/letters. Look them up online. Make a list of the parts.

It will make sense because there is the 'flow' from input (user switches or an RF signal input or etc.) to output and all the components can be looked up online - each chip will have a 'datasheet' put out by the manufacturer explaining how it works. For discrete components like capacitors, inductors, etc. copy their letters/numbers and look them up online.

After you have done this for about 5 pieces of equipment that you'd never seen in your life, you'll get used to it, the cloud of "what is going on" will thin out. After about 10 pieces of equipment you'd never before seen in your life, you will start to have an intuition. After about 20 pieces of equipment you'd never seen before you'll be pissed that it took you so long to find out how easy it is to figure out a circuit.
 

narkeleptk

Joined Mar 11, 2019
466
Long term goal - I'd like to repair vehicle ECU's / Modules and get a good understanding of what I'm looking at.
That's a lot of what I do these days. Honestly the actual repair of the ecu's are not that hard and very repetitive in many cases. The biggest obstacles are, you will never find schematics and you will not find much help from others in general. Your on your own. Most of the time components in the modules are masked and you will need to do a lot reverse engineering for each new modules you learn. The masked versions of the chips out of china do not work 90% so better to spend your time on finding the real IC's. Oh, and much of things pre 2010 have components that are obsolete which makes things even more ... fun?.

There is a lot more to it then just the component aspect of it as well. Much of it is digging around in mcu's and eeprom data learning their structures and repairing it. For me it was pretty easy to get into since I come from heavy immobilizer and module programming and had already been digging around in it for so long but for someone just starting out I think this is probably harder then the component side of things. I also already had the top diag tools and even the manufacturers tools for pretty much every model. These are necessary for a lot of things, even simple things like just testing your repairs. I wont lie, Its costs a small fortune keeping up with tools and manufacturers subscriptions. With out these things you can get by but you will pretty much only be doing IGBT replacements and maybe a few blown diodes here and there.

I noticed someone said something about jumping in the deep end but not to do it with electronics... I disagree. I say Jump right in. Google is there to help. Best place to start is with something broken and don't feel bad if you can't fix it, doesn't matter.
 
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