Pure Electronics Repair. Learn Methodical Fault Finding Techniques / Methods To Fix Almost Anything

LER #221 In this video I show you how to diagnose and repair just about anything, At the day it is all just electronics, yeah? Learn how to apply your knowledge of electronics in a step by step structured METHODICAL way.

I work in collaboration with:
The Electronics Channel (live streams with Carlos and Detlef)

Gran Canaria Uncovered

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TEST METERS
Aneng AN8009
KM601
VC480C+
MESR-100 ESR METER
XC6013L CAPACITOR METER
TM-902C TEMPERATURE METER
LCR-T4 LOW COST COMPONENT ANALYZER
FNB58 USB ANALYZER
PCI POST ANALYZER
TL460S Plus PCI_E ANALYZER
TOOLTOP ET829 SCOPE METER
MULTIMETER PROBE KIT KET05
OSCILLOSCOPES
FNIRSI 1014D
FNIRSI DSO-TC3
FNIRSI DPOX180H
BENCH PSU
NPS3010W
SOLDERING
T12 Station with M8 9501 Handle
M8 9501 HANDLE
T12-BC3 Tip
SUGON T26D
QUICK 861DW
PROS'KIT SS-331H
SS-331H Spare Parts
THERMAL CAMERA
Infiray P2 Pro
MICROSCOPES
Amscope Optical Microscope (copy)
ANDONSTAR AD407

EEPROM Programming
TL866 II+
CH341A
1.8V ADAPTER
CONSUMABLES
NC-559-ASM FLUX
DESOLDER BRAID (I use size 8045)
MECHANIC HX-T100 Solder 63:37 (I use 0.6mm)
ESD-11 TWEEZERS

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Thank you
Richard

[andrewdoherty]

Having spent the majority of my life in electronics ( Radio Rentals, Colourvision, Chandos to name a few) and having attained two degrees I still revert to basics when fault finding. This is a skill that never leaves you, don't forget that just because you find one fault doesn't mean there are not others! Keep up the good work, we need more younger people in the industry to combat the throw away society we have built.

[RingZero]

This is a great electronics repair refresher. Just last week I was able to repair a $5k KitchenAid refrigerator's main board with a broken fuse caused by a shorted rectifier. I had no access to circuit diagram nor does the manufacturer provides it. The board is $650 brand new with a 3 month wait and $500 of factory repair labor, and I was able to fix it with $3 in parts and knowledge in electronics repair.

[LearnElectronicsRepair]

For anyone interested... Handy Andy took the PCB back to the client yesterday afternoon, with strict instructions to check for a short circuit heater element before trying it. This morning before I got up out of bed, I was just thinking about that negative 5V regulator (79M05) and what it may have been doing. I often think about stuff like that, I guess I'm electronically minded through and through LOL.

So anyway, here is my take on it, though I no longer have the PCB to check this.

I think the 79M05 is connected like this: The PIC18 needs a positive 5V supply and yet the Vcc (power in) of the PIC18 micro-controller will be connected to 12V from the transformer and bridge rectifier. The 79M05 minus 5V regulator then holds the 'ground' pin of the PIC18 at exactly 5V less (more negative) than the +12V supply.

This means the PIC18 has a +5V supply but it is referenced from +12V.

Now why? Well there are two relays on the PCB with 12V coils and the PIC needs to switch them on or off. There are two little transistors and diodes near the relays (I checked the diodes). I think the transistors are probably P Channel MOSFETS and switch power to the relay coils, so the P Channel MOSFET connects from +12V, to the relay coil positive end, and the other end of the coil connects to ground. This means the MOSFET can supply the 12V the relay needs to turn on.

To switch the MOSFET off, the PIC18 has to put 12V on the Gate and to switch it on is has to put *less than* 12V on the gate. Because the circuit designer connected the +5V Vcc pin of the PIC18 to +12V it can easily send +12V or less to the P-MOSFET gate and therefore switch the 12V relays with the minimum of components. Simples ehh?

PS the diodes by the MOSFETS will be to stop back EMF when the relay coils turns off 😉

[davematthews]

I really appreciate you the way you explain this stuff. Showing how to troubleshoot a problem on a board you know very little about is one of, if not the biggest, missing links for many people trying to learn these skills. Watching you walk us through how to figure out what might be expected from the components on an unknown board 'in the real world' is what seems to be missing from many similar channels that I've seen. Looking at your list of videos, there's many more useful and educational videos to keep us busy for some time! Subscribed. Thank you.

[theoloutlaw]

Thanks for the video. Really enjoyed the signal flow, explaining the parts in further detail, how they work, and then finding the fault and testing. Look forward to the next one!

[rx]

Really helpful stuff, Richard. Thank you. It's great that you take your time with the board and explain things outside what is strictly necessary for the repair, which makes for a very interesting video.

[RussellTeapot]

26:00 Italian here! Let me translate some words for you:

Macina -> Grinder
Pompa -> Pump (pretty self explanatory)
Motore -> Motor
Sonda Flusso -> Flow Probe

By the way, great video! Very easy to follow even for a beginner like me, I actually guessed some things right as you were going along the board

[vincistradivarius]

The detailed step by step explanations on the various components and their working aided me a tonne. Cheers mate.

[Umtree]

As a 43 year old learning electronics repair.
Your videos are perfect for me.
I am so interested from start to finish.
Your teaching is very good.

[Qcorner]

Excellent content (as usual) Richard! I appreciate the common sense approach to troubleshooting this. Great reminder at the end (on your summary) that you’ve repaired the board but now one needs to determine what caused the issue. If a person absently minded reinstalled the board and put power to it…out comes the magic smoke again.😡. Great work mate. I again learned from this video. Darrell - 🇨🇦

[MetalHeartGunner]

It's always good to watch an experienced technician/engineer work. The short rant at the end is very sound advice, i started learning about electronics out of pure curiosity and ended up coming up with a great side hustle just repairing small stuff, especially heaters, old game consoles and lcd monitors/tvs with basic knowledge of electronics.

[nickyross]

Just stumbled across the channel, I started working in an electronics repair company repairing PCB's very much like these (domestic appliance) at 16. I'm now 30, diverted into automotive electronics and machine maintenance. Very nice to see some of my old trade on YouTube especially now knowing what I've learned over the years!

[ThalesRossiter]

The way you explain all of what you're doing during the repair is just awesome. Another thing that made me happy about this video was seeing you took a few minutes to explain - or refresh - what is a TRIAC and how it works. It helped me a lot on understanding how it operates on the board and how it is related to the failure (short), since I've studied TRIACs some time ago.
You've got a new subscriber.

[RichardRoy]

This was fascinating from a person who knows little to nothing about electronics. Love watching someone explore something in a way that explains a lot. Definitely subbed. I like the bit of advice toward the end as well.

[owenprince]

My brother is an Electrician and asked me how can you fix a board if you do not have the schematic for it. This is how to do it just like you did. I make my own schematic and my brother was impressed that i can do that as I have never taken any course on electronics.

[brucewilliams]

Thanks for sharing your knowledge. I love learning about electronics and you do a great job of explaining what it going on and your process for finding faults.

[markhonea]

Not to mention the satisfaction of a successful repair using your mind as the main tool.👍

[geoffjames]

Very Good... Well explained and far better and thorough examination than most i have seen online, Well done. Look forward to viewing more of your work in the future

[mike-ypuk]

I can't believe this is my second time watching this one. It's actually very interesting how easy Richard makes it look.

[davidh]

I enjoyed seeing your troubleshooting approach. I am amazed that there as so many circuit boards that are tossed in the trash, and replaced with an entirely new one, when there is only a small part needed. I am new to electronics, but I find it interesting. I looked into a course online, but it was geared toward people who work inhouse for companies. It required a lot of expensive testing equipment. I really just want to diagnose problems quickly and fix them. Thank you for making this video!