How To Find The Faulty Component On A PCB Without Schematics : A Very Practical Repair Example!
A customer asked me to look at a controller board PCB from a split air con system. It generates an error code, but I don’t know if the fault is on this PCB or elsewhere. Learn how to spend an hour to methodically work through the PCB with a multimeter, what can we test, what can’t we test, and how to locate the faulty component. These techniques will allow you to fix a lot of PCBs without schematics.
Previous repair video on this Air Con (outdoor controller PCB)
DIY TL431 Tester
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Equipment used in my videos. These are affiliate links, you pay the normal price and I make a small commission.
ANENG AN8009 MULITIMETER
VC480C+ MILLIOHM METER
MESR-100 ESR METER
XC6013L CAPACITOR METER
LCR-T4 COMPONENT ANALYZER
FNB58 USB ANALYZER
TL460S PLUS PCI_E ANALYZER
TOOLTOP ET120MC2 SCOPE
FNIRSI 1014D SCOPE
NPS3010W 30V 10A PSU
T12 STATION WITH M8 9501 HANDLE
M8 9501 HANDLE
YIHUA 982 Soldering Station C210/C245
FNIRSI HS-02 PORTABLE SOLDERING C210/C245
QUICK 861DW
PROS’KIT SS-331H
INFIRAY P2 PRO IR CAMERA + MACRO LENS
TOOLTOP ET13S THERMAL CAMERA METER
ET13S MACRO LENS
OPTICAL MICROSCOPE
TOMLOV TM4K AF FLEX
TL866 II+ PROGRAMMER
CH341 PROGRAMMER
NC-559-ASM FLUX
DESOLDER BRAID (I use size 8045)
HX-T100 SOLDER (0.6MM)
ESD-11 TWEEZERS
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Thank you
Richard
Here is my problem with these kinds of videos: How do you accurately test a component on a PCB and get a good reading???!!! I am currently refurbishing a great old piece of analog test equipment but am getting false readings while still connected to the PCB?? I am finding that {I have to disconnect at least one leg of the item from the board to get a good reading??!! Please, comment and send me an email to help me with this if you are qualified. Many thanks!!
Great video. It might seem obvious but I didn’t see you test the fuse – I have spent countless hours testing components on a board only to find that the onboard fuse is blown or there was a break in the mains cable (not in this board obviously). In fact I once drove 30 minutes to buy a circular saw while doing some home renovation and my previous one had just died. I got home (over an hour after setting out) and plugged the brand new saw in and it did not work. Checked the fuse, all good. Then I plugged in and used one of those live wire tracers and found that the Live wire was broken right where the plug was moulded on. I cut plug off and wired on a new one and it worked. That was 15 years ago and it still works to this day…
@LearnElectronicsRepair Did this board ever get fixed in a future video? I looked but cannot see anything…
algorithm.
What kind of camera are you using to zoom in to such a tiny crammed area? Seems very handy