I really appreciate you showing us from start to finish and never edit the video if things go wrong. You are a very honest man, never change you are one in a million, most people are bullshitters. You are honest because you know, you know what your doing. Too many people in this world bullshit their way though life. What a refreshing change.
I have great admiration for you Richard, as I am sure all the other punters agree, you've unashamedly exposed yourself to the world, so had no choice but to fix this fault. And fix it you did. Well done Sir. I for one have learnt so much from this triumph, and many of your other videos. Cheers Adam.
Hi Richard, thanks for the content. To align the mosfets with heat zink you could just stick them in their place, mount them to the heatzink, and then either - solder one or two leg from the top, as it's a double sided board you have pads on top . Then remove heatzink and solder underpads. OR - just use some hot glue to temporarily glue their legs to the pcb, demount them from heatzink and solder below while their glued. cheers.
I like the narrow pointy tips but I always cover mine with a bit of heat- shrink tube. For any interested parties we have just had a British 1,2,3 on the grid for tomorrow's British GP for the first time since Jim Clark, Graham Hill & John Surtees in 1968. 😁
Great job to unsoldering the SMD components and putting back on the new... and not just SMD soldering and unsoldering....all the checking and measuring...everything is great..
Remote rural off grid NSW here prime time TV ah that's the screen one can see from space gets turned on only twice a year , ANZAC Day and the New Years Eve fireworks in Sydney :) Have to run the generator to power it even on standby, full solar and wind here :) Don't miss the coast at all the cities even less.
For removing tricky components use the Mr Solder Fix technique. Bend some solid core copper wire to fit all the legs then flood your tip against the cage and move around. The copper cage will act as one tip. He also did a video showing how sticky foil tape is better at protecting against heat than kapton. Would it not be a good idea to add some super thin heatshrink to your long thin probe needles? You can also buy similar probes that clip over standard probes. If that power supply flip flops between two capacitors, sometimes you have to check the caps are withn tolerance of each other or one does all the work and can take out the circuit.
i've found some small gauge screw terminals, cut off the plastic parts and screwed onto the probe tips - together with sewing needles. Finished off with a thin gauge wire insulation. Works fantastic and I fully undertand why you are using thin probe tips.
For future reference, you could have put the Mosfets on the opposite (back) side of the heatsink, then soldered them, and then mounted them back on the correct side, and then you'll have all of them perfectly aligned at the same height. This is the sort of simple trick I usually realize after I'm 90% finished doing it the hard way.
I really think you should give chipqwik another go some time... I just laid down two lines of the stuff (with flux) covering the pins to remove a TDA8950TH HSOP-24 device during an old dB FlexSys FM10 repair and removed with nothing more than a single BC12 tip iron at 350C, slid down both sides a couple of times to mix with existing leadfree solder and it just pushed off the board, no danger of overheating anything... wicked away the residue, quick clean with Ultrasolve or IPA and ready for replacement :)
It seems that for some transistors (example BC847...BC847R) it is possible to order parts with swapped pins (see eevblog: "Do they exist? SOT-23 pnp transistors with non-standard pinout")
When ready to power up again, bring it up slowly on your variac whilst monitoring voltages and board with thermal camera, may point to something before it shorts those transistors again (the other thing could be fake components, but possibly more likely they'd blow under load if so - or under-rated voltage-wise, and I guess tend to be the more rare expensive components that are counterfeited)
Richard, why don't you order components from Mouser or Digikey? Both have Spanish and UK sites and at least Digikey does Europe to Europe shipping. Will be a bit more expensive but at least you'll have the peace of mind that what you get is genuine and good quality.
Hi Richard🤗🤗 If I were you, I would have tested the amplification factor of the MOSFETs. The Chinese are not always honest. To test ist, dont soldier the drain pin from the mosfet and let us show the oscillograms.
There is NO amplification factor with a MOSFET They are electronic semiconductor switches only Do not confuse a MOSFET with a TRANSISTOR You most likely do not know the difference between Passing and overtaking nor the difference between Someone and Somebody nor the difference between The UNITED STATES OF AMERICA and The United States of America So write an essay explaining the differences Then I will give you more homework
@andrew_koala2974 Note 6. Sit down and shut up. Mosfet Saturation : UGS > UTH und UDS > UGS-UTH IDS = (ß/2) (UGS-UTH )2 . ohhh sorry. especially for the super know-it-all from Burgerland. ohh i forgot Mosfet, Mosfet, Mosfet, Mosfet . 🤣🤣 What is your problem?? Does your wife have to many headache's???. @Richard, please measure the deltas of the mosfet's rise times. Colloquially also referred to as an amplification factor..
@@andrew_koala2974 Mosfets act as voltage-controlled current sources - ergo they can either be amplifiers or switches. Mosfets are not 'electronic semiconductor switches only' Many Class A/B amplifiers use Mosfets as the output devices for good reason such as they are easier to drive and are naturally imune to thermal runaway. A MOSFET *is* a type of TRANSISTOR, just analyze what the abbreviation stands for Metal Oxide Semiconductor Field Effect Transistor. I agree that Mosfets don't have 'gain' in the same way that a Bipolar Transistor does, but that does not mean they can't be used to amplify a signal. As an aside I've noticed you appear to have a fixation with grammar. This is neither an English language nor a geography forum, but seeing as you mention it, I can't figure out the difference between The UNITED STATES OF AMERICA and The United States of America is either, other ethan one is in capitals and the other is in initial case 🤔
Richard, this must have taken you ages to record this. I wish when i was learning i had this kind of in depth tutorial. And i still learn stuff from you, don't know how you run a shop and do this as well. Sponge bob square pants condom's rule 😂😂
Discipline - Make it a habit to connect in this order - as is shown on the display RED GREEN BLUE P1 P2 P3 You have it connected GREEN RED BLUE Yes - we know that the instrument will identify pin function However - it is not about that It is about having an organized and disciplined mind instead of a random cotton candy mind. Develop an organized mental process. You are half-way there - just complete the job Your mind is fraying at the edges - when you let the little things go - it does not take long before you start letting the bigger things go and eventually you end up like Joe Biden. I hope this helps you to organize yourself and stay on track
Another option is to drill four holes aligned with the mounting holes thru the heat sink at least 1/2" and solder thru those holes. You cooked two mosfets running through a current limiter in 2 seconds??
Yeah this is an interesting topic and I will be talking about the likely reasons for this, and how to diagnose safely faults in this situation, after the weekend
I am an electrician and have been watching you for years, you are a legend and have taught me allot
I really appreciate you showing us from start to finish and never edit the video if things go wrong. You are a very honest man, never change you are one in a million, most people are bullshitters. You are honest because you know, you know what your doing. Too many people in this world bullshit their way though life. What a refreshing change.
I have great admiration for you Richard, as I am sure all the other punters agree, you've unashamedly exposed yourself to the world, so had no choice but to fix this fault. And fix it you did. Well done Sir. I for one have learnt so much from this triumph, and many of your other videos. Cheers Adam.
Hi Richard,
thanks for the content. To align the mosfets with heat zink you could just stick them in their place, mount them to the heatzink, and then either
- solder one or two leg from the top, as it's a double sided board you have pads on top . Then remove heatzink and solder underpads. OR
- just use some hot glue to temporarily glue their legs to the pcb, demount them from heatzink and solder below while their glued.
cheers.
I like the narrow pointy tips but I always cover mine with a bit of heat- shrink tube.
For any interested parties we have just had a British 1,2,3 on the grid for tomorrow's British GP for the first time since Jim Clark, Graham Hill & John Surtees in 1968. 😁
Great job to unsoldering the SMD components and putting back on the new...
and not just SMD soldering and unsoldering....all the checking and measuring...everything is great..
I enjoy watching your work. It reminds me of an artist making a painting. Really nice work.
Saturday night at 8:30, prime time tv in Australia and on comes Rich! I could not ask for a better night's tv! Thanks mate!
Remote rural off grid NSW here prime time TV ah that's the screen one can see from space gets turned on only twice a year , ANZAC Day and the New Years Eve fireworks in Sydney :) Have to run the generator to power it even on standby, full solar and wind here :) Don't miss the coast at all the cities even less.
For removing tricky components use the Mr Solder Fix technique. Bend some solid core copper wire to fit all the legs then flood your tip against the cage and move around. The copper cage will act as one tip.
He also did a video showing how sticky foil tape is better at protecting against heat than kapton.
Would it not be a good idea to add some super thin heatshrink to your long thin probe needles? You can also buy similar probes that clip over standard probes.
If that power supply flip flops between two capacitors, sometimes you have to check the caps are withn tolerance of each other or one does all the work and can take out the circuit.
There's a Mend it Mark video which shows kapton tape makes a great thermal transfer material, old habits die hard (me included).
i've found some small gauge screw terminals, cut off the plastic parts and screwed onto the probe tips - together with sewing needles. Finished off with a thin gauge wire insulation.
Works fantastic and I fully undertand why you are using thin probe tips.
For future reference, you could have put the Mosfets on the opposite (back) side of the heatsink, then soldered them, and then mounted them back on the correct side, and then you'll have all of them perfectly aligned at the same height. This is the sort of simple trick I usually realize after I'm 90% finished doing it the hard way.
I really think you should give chipqwik another go some time... I just laid down two lines of the stuff (with flux) covering the pins to remove a TDA8950TH HSOP-24 device during an old dB FlexSys FM10 repair and removed with nothing more than a single BC12 tip iron at 350C, slid down both sides a couple of times to mix with existing leadfree solder and it just pushed off the board, no danger of overheating anything... wicked away the residue, quick clean with Ultrasolve or IPA and ready for replacement :)
Narrow and pointy is good. I use something similar except the ones I use are insulated and adjustable.
It seems that for some transistors (example BC847...BC847R) it is possible to order parts with swapped pins (see eevblog: "Do they exist? SOT-23 pnp transistors with non-standard pinout")
did you cover the part of the voltage selector yet, or is that for another video to come ?
When ready to power up again, bring it up slowly on your variac whilst monitoring voltages and board with thermal camera, may point to something before it shorts those transistors again (the other thing could be fake components, but possibly more likely they'd blow under load if so - or under-rated voltage-wise, and I guess tend to be the more rare expensive components that are counterfeited)
What zoom lens are above ur head? They zoom in really well
Heya, alread so there must be a short some were else. but I got it till now lol nice
Richard, why don't you order components from Mouser or Digikey? Both have Spanish and UK sites and at least Digikey does Europe to Europe shipping. Will be a bit more expensive but at least you'll have the peace of mind that what you get is genuine and good quality.
I have ordered from Mouser on occasion but the minimum €20 postage charge is a bit off-putting and also rather excessive IMHO
Hi Richard🤗🤗
If I were you, I would have tested the amplification factor of the MOSFETs. The Chinese are not always honest.
To test ist, dont soldier the drain pin from the mosfet and let us show the oscillograms.
Hi Lightrunner that sounds interesting, thanks
There is NO amplification factor with a MOSFET
They are electronic semiconductor switches only
Do not confuse a MOSFET with a TRANSISTOR
You most likely do not know the difference between
Passing and overtaking
nor the difference between Someone and Somebody
nor the difference between
The UNITED STATES OF AMERICA and
The United States of America
So write an essay explaining the differences
Then I will give you more homework
@@andrew_koala2974 Winker!
@andrew_koala2974 Note 6. Sit down and shut up. Mosfet Saturation : UGS > UTH und UDS > UGS-UTH IDS = (ß/2) (UGS-UTH )2 .
ohhh sorry. especially for the super know-it-all from Burgerland. ohh i forgot Mosfet, Mosfet, Mosfet, Mosfet . 🤣🤣
What is your problem?? Does your wife have to many headache's???.
@Richard, please measure the deltas of the mosfet's rise times. Colloquially also referred to as an amplification factor..
@@andrew_koala2974 Mosfets act as voltage-controlled current sources - ergo they can either be amplifiers or switches. Mosfets are not 'electronic semiconductor switches only'
Many Class A/B amplifiers use Mosfets as the output devices for good reason such as they are easier to drive and are naturally imune to thermal runaway. A MOSFET *is* a type of TRANSISTOR, just analyze what the abbreviation stands for Metal Oxide Semiconductor Field Effect Transistor. I agree that Mosfets don't have 'gain' in the same way that a Bipolar Transistor does, but that does not mean they can't be used to amplify a signal.
As an aside I've noticed you appear to have a fixation with grammar. This is neither an English language nor a geography forum, but seeing as you mention it, I can't figure out the difference between The UNITED STATES OF AMERICA and
The United States of America is either, other ethan one is in capitals and the other is in initial case 🤔
Richard, this must have taken you ages to record this. I wish when i was learning i had this kind of in depth tutorial. And i still learn stuff from you, don't know how you run a shop and do this as well. Sponge bob square pants condom's rule 😂😂
Discipline - Make it a habit to connect in this order -
as is shown on the display
RED GREEN BLUE
P1 P2 P3
You have it connected
GREEN RED BLUE
Yes - we know that the instrument will identify pin function
However - it is not about that
It is about having an organized and disciplined mind
instead of a random cotton candy mind.
Develop an organized mental process.
You are half-way there - just complete the job
Your mind is fraying at the edges - when you let the little things go
- it does not take long before you start letting the bigger things go
and eventually you end up like Joe Biden.
I hope this helps you to organize yourself and stay on track
I fail to see why the probes need to be connected in any particular colour, it's not like there is some convention to follow here. 😵💫
Another option is to drill four holes aligned with the mounting holes thru the heat sink at least 1/2" and solder thru those holes. You cooked two mosfets running through a current limiter in 2 seconds??
Yeah and we are going to have a good talk about that in the next video after the weekend 😉
There must be a short circuit somewhere, the mosfets would not break if the resistor or something else is open
Notice it didn't go bang straight away and the amplifier PCB was disconnected from the PSU HT
2 mosfet under current protection cooked in less that 2 sec is a magnum opus
Yeah this is an interesting topic and I will be talking about the likely reasons for this, and how to diagnose safely faults in this situation, after the weekend
We are waiting Rick