Really enjoying all your videos. I’ve leaned so much from them. Our lives are very similar. Im about the same age as you. We did similar things as kids. Playing out in old scrap yards in Leeds. Pulling televisions apart and messing about. We used to break open transformers and pull out the metal E shaped things. We called them E flyers and threw them about, they would glide for miles. 😂 Constantly getting told off by my old mam for taking everything apart. Where I lived in Hunslet in the 70s the council were pulling down loads of old back to back houses. There was no fences back then so we would clamber about in them and messing with old wooden fuse boards. I’m amazed I’m still alive. Would love to hear more tales of those days.
@sivoltage5 ай бұрын
Brilliant thank you, Looking forward to the next one.
@Chief_Engineer5 ай бұрын
There is a universally accepted symbol for a light bulb - a circle with a diagonal cross inside. It doesn‘t have to look like a chef‘s hat (although I admire the artwork). 😂
@Bibekanandaroy-tn5jmАй бұрын
Many many thanks sir ❤❤
@francismannion70754 ай бұрын
Thank you for a very interesting lesson.
@c1q33 ай бұрын
thanks for the video.
@Arachnoid_of_the_underverse5 ай бұрын
Nice explanation thanks for that.
@Gonzi-ze1sk5 ай бұрын
i learning a lot from you
@LearnElectronicsRepair5 ай бұрын
You're welcome
@blindkeith5 ай бұрын
looking forward to the next vid on this .
@ralphj40125 ай бұрын
It will be interesting (probably, just to me) to see whether the lamp reacts faster than any dodgy mosfets and if it withstands the 320V DC (albeit for a very short period).
@LearnElectronicsRepair5 ай бұрын
I think this is something we can play with on the next live stream 😉
@viniciusvbf225 ай бұрын
Amazing content! I was never able to confidently fix PSUs. Unless it was something pretty simple, like replacing capacitors, they've always shorted again just after powering them up. I've change every component in the PSU (but the transformer) once, and it still shorted again right after powering it up 😅🤷♂ To me, people like Haseeb are magicians.
@amirfathirad29654 ай бұрын
easiest way to add a light bulb to the mosfet side of the circuit is to use the capacitor leg, take out the electrolit capacitor and use wires to attach it to the board and light bulb etc, just you have to be careful with soldering electrolite capacitors, they are a little bitexplody when getting warm from soldering iron
@robtitheridge97085 ай бұрын
Takes me back to the days of the earley PACE set top boxes chopper transitor shorts change it and anything that looked burnt turn on and bang .thank god somone bought out a repaire kit .
@jkmac6255 ай бұрын
I'd be interesting in watching a video about mains isolations transformers. Most of the ones I've found online seem to be 240 to 120 step down transformers rather than 240 in 240 out. Thanks.
@andymouse5 ай бұрын
Maybe bring it up on a Variac and look for hotspots or find the short on the board, But it will be interesting to see the bulb inserted in like this as I haven't seen it before ! I look forward to part 2.....cheers.
@justmc625 ай бұрын
Great as always Rich.. Looking to set up a permanent isolation transformer on my bench. Will appreciate your thoughts on the alternate solutions you spoke about ...Thanks
@fey49495 ай бұрын
It would be nice if you show us the all of the different methodes as you suggested. We could see the pros and cons. Thanks Ritchie.
@LearnElectronicsRepair5 ай бұрын
Part two mostly recorded 😉
@Foobar_The_Fat_Penguin5 ай бұрын
26:56: Instead of cutting traces to insert the light bulb, couldn't you also desolder one of the big filter caps and reattach it with a pair of wires and then a bulb in series? If the "blow-up current" comes from the caps, it should suffice to limit their output, no? You'd probably still need the limiter on the input for other faults (e.g. the bridge rectifier suddenly going short) but you don't have to damage the PCB or bend mosfet legs or stuff like that.
@grahambambrook3135 ай бұрын
Hi Rich, Decades ago my old dad who was a 'sparky' for the SWS which became the Midland Electricity Board if you remember them. He showed be a way of using a lamp holder on flying clip leads to help diagnose this sort of problem and to this day, I keep a 15W or 25W, 240V pigmy bulb set up like this in my tool collection. Most of his job involved transmission @11kV and above so I guess he did not wave his trusty test lamp about too often at work 🤣 but it came in handy on domestic duties. I found through my teenage years that this can be a useful technique for finding automotive issues, too! Incidentally, for many years I could not figure out how I got a nasty 'belt' from my (12VDC) car horn on one occasion, having had one or two from ignition coils and the like it was a bit of a shock (pun intended)! Far more recently, through programs like yours and others, I discovered the mystery of back EMF as the horn operated when shorted to earth through a relay as there is quite high current through a horn circuit!! We live and learn, as 'tis said!🤯
@nasosst30925 ай бұрын
Thanks again Rick. But are we positive that the aliexpress replace components are good for the job?
@LearnElectronicsRepair5 ай бұрын
No. That is one possibility here
@ianhaylock74095 ай бұрын
Could also use a variac to reduce the input voltage.
@SpinStar19565 ай бұрын
Hi there, could I ask your source for the nice graph-paper? I’ve been looking for some with smaller graduated squares like yours. I looked on Amazon but couldn’t match yours Richard. I use it for schematics and PCB initial layout. Thanks & 73! 😊
@TallyTechandTroubleshooting5 ай бұрын
Fantastic! Is there a "current limiting lightbulb" explanation somewhere on your channel. Very interested in putting one together. Thank you for your patience, Richard and thank you for your channel!!
@georgeprout425 ай бұрын
Dim light bulb tester is probably the term you need to search. A 100W old school tungsten lamp, ohms law takes ~0.4A @240V. If the unit under test is internally shorted then the lamp turns on at full brightness and the unit is limited to ~400mA. But the voltage drop is all on the lamp. The result is no bang, no damage. If it lights up dimly, the test passes and you can plug it in directly as you know it's not shorted. A brief flash can be ignored, inrush current will do that.
@LearnElectronicsRepair5 ай бұрын
Yeah I made at least one video about that kzbin.info/www/bejne/imO4f4mliZmaeas The one I use mostly is 65W halogen
@TallyTechandTroubleshooting5 ай бұрын
@@georgeprout42 Thank you!!
@TallyTechandTroubleshooting5 ай бұрын
@@LearnElectronicsRepair Thank you, Richard!!!
@Dutch_off_grid_homesteading5 ай бұрын
Heya, love the trouble shooting thought. as with a accident I sorted my Mppsolar inverter the MPPT pcb probbebly gone try to repair it my self already openend the inverter (wouw what a lot of wires in there took foto so I later can see hohw everything is connected thinking of filming it ut don't know jet ( don't want to look as a fool if I can't repair it) also looking at youtubers who already did some repair work on these imverters
@davet38045 ай бұрын
To limit current ..Could you not switch big caps for low value 200v caps to check unit is running with no load ??
@ciobanurivelino38445 ай бұрын
It's normal to you, to know that trick. As is an Old School trick like you and me. Regards!
@talkintech93635 ай бұрын
I bought a brand new 500W PSU, powers up ok but when plugged into the motherboard it doesnt power up, mother board is ok as when the old psu is plugged in it powers up normally. What should I be lookung for to repair it?
@jimgross55 ай бұрын
Just my opinion but if I am repairing something for a paying customer I will never trust mosfets purchased from aliexpress or ebay go with a reputable seller like Mouser and DigiKey. Yea you pay more but they are not fake.
@stevewebb19415 ай бұрын
Is the power supply going through the isolation transformer and oscilloscope
@LearnElectronicsRepair5 ай бұрын
Only connect the DUT to the isolation transformer, you can then connect your grounded test equipment (one at a time if you connect them to different ground points or all together if you use a common point) to anywhere you like
@Pozitiv_ion5 ай бұрын
but why should we insert the bulb into the mosfet circuit, to see that they are burnt... isn't it easier to check them and all the connections with the surrounding resistors and so on?
@LearnElectronicsRepair5 ай бұрын
You are missing the point, in the previous video I replaced the shorted mosfets checked all the surrounding resistors and so on. It powered up for a few seconds then the replacement mosfets went short. So we need a method to diagnose the problem in this sort of scenario. Previous video on this repair : kzbin.info/www/bejne/a4mvpmyOmayjpZo
@Pozitiv_ion5 ай бұрын
@@LearnElectronicsRepair sorry, I haven't seen the previous episode. I'll look right now...