How To Locate Trace Diagnose & Fix Intermittent Faults In Electronics: With Practical Repair Example

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@garypoplin4599 3 ай бұрын

3:50 - Thank you, Richard! You just gave me an idea of a name for the new widget I’ve created: Quite-A-Tite (coming soon to an island near you).

@gadgetmind 3 ай бұрын

We once had some gear we were designing fail in Japan but not in out Leeds office. We quickly decided it was heat, and threw a fluffy jumper over it, and fail, yay! We then tracked it down to one FPGA using hot air, and then put a wirewound resistor connected to a bench supply on this so we could keep it warm. We tracked the issue to bad VHDL with a race, and had it fixed within an hour. The engineer decided to up the current to prove the point, hit 50C with no issue, and went off to celebrate with a pint or two for lunch. While he was out, colleagues heard a clatter and it was the FPGA - still with big old resistor strapped to it - desoldering itself from the board and hitting the bottom of the case. His job after lunch was hand soldering a new FPGA onto the board, which was lucking QFP rather than BGA.

@darrenwardell3079 3 ай бұрын

What a cracking video👍 I have learnt so much by watching your channel. Many thanks👍👍

@jeisonsanchez4842 3 ай бұрын

5:24 that’s how I used to try my hand at electronics repair 😂

@Lightrunner. 3 ай бұрын

Hi Richard 🤗 your knowledge of repairs is inspiration.👍

@cskeet1320 3 ай бұрын

Great video Richard. I find wooden chopsticks good for pushing on components to localise dry joints, cracks in components and tracks. I use cans of "compressed air" to freeze components. In the UK, they only cost a pound from pound shops. Much cheaper than freeze spays.

@LearnElectronicsRepair 3 ай бұрын

Would the compressed air can work here for example, I don't think the workshop temperature ever drops below 25C and From March to November it's usually 30C. It might get closer to 21-22C in Jan/Feb. I just checked this morning Oct 4th 10:00am its 29.1C ambient. I've just switched the air con on. There is no artificial heating in the shopping centre by the way

@OnStageLighting 3 ай бұрын

@@LearnElectronicsRepair I use the cheap poundshop air cans too. Once identified a dodgy TV chip that the picture improved when being frozen. Canned air, or freeze spray, was what I used a lot to find shorts before thermal cameras made it easier.

@cskeet1320 3 ай бұрын

@@LearnElectronicsRepair It's called Air Duster. It comes with a straw for precision use. It contains a volatile HCF. It freezes down to -32 dec C as it evaporates on the component. It should be fine in warmer climates like the Canaries. Incidentally, it is rubbish as an Air Duster - it just sprays a fine mist of coolant!

@twithheldmwithheld8938 3 ай бұрын

Excellent explanation, you truly are good at this! ✌

@Dutch_off_grid_homesteading 3 ай бұрын

Heya, nice follow up video and you have done it, 1 of the most difficult problems to fix "intermittent fault" I hate them wel done richard

@alandrury9955 3 ай бұрын

Yes, every workshop should have a "knocking stick", a bit of wooden dowel or plastic rod of some sort about a foot long. Great for tapping on small areas or individual components. Also good for pressing on things, sometimes just flexing the board or pushing on a component will provoke the problem or reveal a bad connection or mechanical problem you wouldn't otherwise notice. With a nice insulated prodder of reasonable length you can safely have a go at the insides of pretty much anything while its powered on

@AnnaVannieuwenhuyse 3 ай бұрын

Percussive maintenance was never gone 😅

@gillesparisien4383 3 ай бұрын

While the fan is that noisy i would replace it or trý to clean it n balance

@Bristoll170 3 ай бұрын

My go-to for localizing intermittent areas is a tooth brush. The plastic handle is great for tapping to about the right area, then the bristles seem to have just the right pressure to zoom in to the area of concern. Cheers Pete'. New Zealand.

@LearnElectronicsRepair 3 ай бұрын

That sounds like an interesting technique Pete. Thanks for the suggestion.

@melvilib 3 ай бұрын

I may have missed it but I don't think you mentioned swapping identical modules to see if the fault moves. I think you could have done that wit that amp?

@toolsarecool 3 ай бұрын

You missed it 😎

@Piasecznik72 3 ай бұрын

Compressed air can hold upside down works same way as freeze spray. I believe they are basically the same. Freeze spray has internal straw taking liquefied gas from the bottom but compressed air does not have it just to spray evaporated gas.

@rickardandreasson5095 3 ай бұрын

I worked on another old amplifier where some capacitors leaked and damaged the transistors under the heatsink. It was covered by hardened white glue. Those leaky capacitors can cause quite alot of damage

@LearnElectronicsRepair 3 ай бұрын

Yes. Though not as much as old leaking batteries!

@OnStageLighting 3 ай бұрын

When doing customer repairs, the biggest issue with intermittent faults is being able to verify that any intervention has solved the problem. This is bad enough with local clients, but mail-ins even worse. No point having a call back saying 'it worked for a bit and is now doing it again.' Actually, thinking about it such situations are to be 'commercially avoided'. Boomerang jobs, we call them.

@ericjackson7810 3 ай бұрын

Hi Rich. love your videos but i feel i have to mention as it grates on me when you say IsopropAL instead of isopropYL or Isopropanol lol. just a little gripe of mine. keep up the great vids mate. ive learned a LOT from you. 👌

@rodd8170 3 ай бұрын

Its easier to just say IPA.😂

@rickardandreasson5095 3 ай бұрын

In case of trimmer pots and pots for volume control i used wd40 penetrating oil. I cleaned up an old amplifier from corrosion using a brush and wd40. No noice at all and it still works perfectly today

@semiRockethr 3 ай бұрын

WD40 is an oily substance, could cause some resistance and burning on higher current devices, no? Contact spray is better solution.

@Lightrunner. 3 ай бұрын

Wd40 isn't a cleaner. Bad thing for electronics .

@itrema 3 ай бұрын

Wd40 is the contrary of oil, at first glance you can see it as oil, but, in fact, it dries, and strongly. It is totally forbidden to use it in faders, or you will kill them

@LearnElectronicsRepair 3 ай бұрын

@@itrema WD40 is a Water Dispersant, not an oil. It's also a perfect product. It's been around for decades but they obviously can't improve it (like they do with washing powder and floor cleaner) otherwise we would be on about WD47 by now... yeah? I do have a can of 'WD40 Limpiador de Contactos' and that is switch cleaner. It doesn't smell as nice as regular WD40, which is a bit addictive I think 🤐

@TheContrarianThinker-S0 3 ай бұрын

Intermittent faults can be right pain in the ass; and, not just in electronics 😮‍💨

@gregwmanning 3 ай бұрын

14:00 power resistor looks like it needs a bit more solder

@Foobar_The_Fat_Penguin 3 ай бұрын

I once had a cracked TVS diode in a hard drive. Depending on how the layers shifted during operation, it would sometimes be open and the drive worked. And sometimes, it would short and the drive stopped working. I'm not sure how common that is (I'm just a hobbyist, my sample sizes are small), but TVS diodes seem somewhat prone to failure. It wouldn't surprise if a certain percentage of those were intermittent.

@LearnElectronicsRepair 3 ай бұрын

That sounds like the same failure mode for MLCC SMD capacitors. You would think something with a crack in it would tend to fail open circuit, but those are made more like a wafer biscuit so when they crack one wafer touches another wafer. And that creates a short.

@AnnaVannieuwenhuyse 3 ай бұрын

@@LearnElectronicsRepairit is to some extent the same type of failure yeah. Their construction shares some elements