Loved that introduction, it was purrrrrrrrrrfect. Great job on the repair. I have tried that over current on those types of displays before. Never worked for me.
Generally in my experience: overall dim means oxidization, and difference between characters means aged phosphor. Note that "burning off" oxidization only works well when there is enough unoxidized getter metal inside the tube.
Glad it was a nice and easy repair for a change! Not sure if it effects this generation of HP gear as much, but I'd replace those yellow Rifa brand class X and Y mains caps any time I see them. Had two HP instruments get very sticky and smelly on the inside from where they exploded!
I tried that same method for the VFD in my 34401A DMM with pretty much the same result (didn't manage to burn up the filament, though!). Your side-by-side comparison with the new VFD makes it quite apparent that the issue is with the phosphor and not the filament. Funny how so many HP/Agilent products from this era have this issue, yet all the VFD clocks in appliances around my house still look reasonably bright despite being on 24/7 for the last 10-20+ years.
I wonder what the science is behind the failure. Like is the phosphor depleted, or has it been poisoned and coated, because if it's the latter maybe reversing the current. They remove chrome plating by reversing the polarity.
I have a stereo that's at least 20, if not 30, years old, running 24/7. Its VFD is still easily visible in daylight, although it has slightly darker bands right under the filaments (so it's failure will be burning out the phosphor, not oxidation on the filaments). Maybe the HP devices are being driven harder to be brighter to be very visible in a lab environment (which should be a very bright workplace) and degrade faster because of that.
Glowing the filaments only works if your filaments have been poisoned by DC bias. Every VFD I've dealt with specifies AC to the filaments to counteract this problem, I'd strongly suspect HP knew about this issue when designing this instrument. This unit had "phosphor fatigue" (easily identified by the phosphor segments looking dingy and inconsistent); there's no repair for that.
I've also experimented with rejuvenating VFD's and have found that getting the filaments to just barely glow for about 10 minutes seems to work the best. There is a point where you you can go to far, even with a faint glow. Also, just letting them operate with the most characters illuminated for a couple days sometimes brings them back. I haven't tried it but I think baking them in an oven around 100c for 24 hours would give favorable results. Great video!
excellent job. brilliant. 2:45 I was sure it's the rectifier. But I also expected a broken transistor. 21:25 too bad, I wished we could see if this procedure made any difference at all
Cryo-EM microscopes have a similar issue with residue accumulation on the capacitor plates, which end up forming spark gaps and shorts. Preventative maintenance procedures are to run it hot to prevent catastrophic failure. (I mean, the electron source itself is a pain to deal with hah!). At Caltech, the cleaning procedure is to effectively do what what Shahriar was doing... but at longer durations. This is consistent with vacuum tubes restoration that use (unthoriated? IIRC) tungsten -- 110% standard voltage @ 30 minutes to burn off any aggregate material. Side-note, (no personal experience on this one..just remember someone mentioning it), on old fluorescent tubes (i.e. those ancient T5's), the single-ended ballasts would burn in unevenly. So much so that particulate from the electron source would be visible biased towards the emitting side (this is with a properly configured setup-- if other elements in the setup like your ballast are misconfigured/failing, then you have bigger problems than this). If you 180 them, you (in theory for sure, in practice, I believe as well) should be able to extend the mean time to failure
Also A+ Shahriar, great episode. This is definitely an "experiment' because you actually did experiment! This (personally) is an episode I would pay for, 10x over any sort of review. (In my personal opinion, the best episodes are the in depth "tutorials on non linear.." and "tutorials on ___ filters" (episode 9,10), then the "proper usage of obscure stuff' (episode 26), teardowns of things like the Agilent optical stuff most of us don't tend to use in our day to day lives. Repair videos like this where you experiment are great as well.
21:51 AFAIK you're NOT supposed to get the filaments white hot but mild red. And given how hard it is to find replacements I think it's a good idea to test first if a lower current did the job.
In some cases you can increase the brightness just by increasing the negative voltage going to the display. HP tends to run them on -5 volts so you could increase that quite a bit and not have to bother with the filaments at all.
I did a transformer rewind once for a similar power supply. It still works perfectly, so it is possible to disassemble the transformer and rewind it. :) just saying dont give up if the transformer is dead.
I have an old Casio calculator with one of those luminescent tubes and in poor light you can see the filament glow. Its been like that since I bought it new in 1974.
I fixed one that would de-regulate above ~12volts. I replace the rectifiers, Pass FETS, and then the Gated-able Diodes (I understand that they are not exactly Diacs or triacs). Still it deregulated. Would you believe the whole problem was the crimping of a spade connector on the heavy secondary transformer wires? Instead of zero ohms from the XFMR to the PCB, it was much higher (maybe 1000 ohms), That explained why I could still see the proper A/C coming from that transformer tap, but there was no current behind it. I took the spade off, re-crimped and soldered it and it worked great after that. Not bad for finding it the hazardous trash at work. I might of had maybe $20 in the parts I tried; that were not the problem.
I think in these Agilent power supplies rectifier bridge is most common problem. I had one with exactly same failure and I have seen one British guy's repair videoon TH-cam also with burned and cracked rectifier.
Nice Repair. But this burning of the oxide doesn't make much sense to me. Isn't metal even more reactive when it is hot, so it is oxidising even faster? Anyways worth a try I guess. Keep up the good work.
+jolo0011 k You'd think. But that is not what happens. When you bring metal up to temperature the oxide burns off, and you are left with clean metal. I've done it many times with an oxy-acetylene torch on rusty hardware. Glowing metal up burns the rust away.
I wonder how hard it would be to reverse-engineer the VFD and make an LCD replacement. Definitely more than $90 worth of work, but could be a fun project. Sadly each device is different so there's no universal way to do this, otherwise such a project would be more useful.
I've replaced an ancient LCD display in an old Fluke 8050A DMM with a graphical LCD display and STM32 micro that decoded the scanned display signals. It was a fun project..
Question... How do you get the shots where you're behind the camera without it being in your way? I'm trying to make similar videos but my camera is in my way and I find it really distracting. Thanks!
Here is a quote from an Itron data sheet on VFDs, "Since the lifetime of a VFD is dictated by the extent of evaporation of oxide materials coated onto the tungsten filament wires, it is critical that the filament voltage is supplied within the specified ratings." They made at least some of the HP VHDs. Do they actually coat the wire with material to enhance electron ejection and so burning it off would ruin the display? Or are they talking about oxides that form from use? It seems to me there may be a coating on the wire that you don't want to burn off which is why the display stopped working.
Thanks for the video. How do you record video when you are working on something that is in front of you? Is the camera above your head and you are ducking down?
Does E3632A uses single tap for each of its outputs over entire range, or does it switch taps at some point (i.e. 15V, on 0-30V range)? Update. Well, it looks it is not, I see no relays, and the one of the main transformer taps is going straight into rectifier, so it will operate from single tap over entire range, at least when manually selecting 30V range. I suspect another tap must be selected manually, to provide 15V range. And when using 14V, it will not switch automatically to 15V range.
where did they get those new old fluoruscent displays from? how do you usually control the brightness on these displays? could it have been repaired by just increasing voltage/amperage on that circuit?
I'm facing Unreg issue, with my E3634A Observations : 1) Self Test pass . So that's a relief . 2) No errors reported. 3) OVP : 25V, OCP : 4A 4) Display Limit : 25V , 2A 5) Output On with 25V,7A Mode : a) Setting 0V, 0A- Recorded (DMM) 42.62V b) Output Off : Holds 42.01V (DMM) , takes close to 3-5min to 0V 6) Tried to change voltage and current setting on PS, But cannot change anything. DMM records 42.62V Do you know how to fix it ?
If that transformer was shot, it would be a likely a short in the windings yeah ? Couldn't you test for continuity between taps to identify the failure point in the xfer, then use Kapton (or even electrical tape), rather than replacing the whole (heavy and expensive) xfer?
A Transformer is basically just a coil of wire, so a continuity measurement (wich measures DC-Resistance) would read a short circuit anyways (if the transformer is good or when some windings shortet together). If a transformer burns out (wich it would if the input fuse does not blow), it usually heats up from the inside outwards. That means that you have to unwrap a LOT of transformer wire to even get access to the fault. Also the melting coating on the wires tends to glue it all together. But if its a mechanical fault were for example the one end from the wire crosses the outside layer you could may be re-isolate that particular failure point with epoxy or kapton (-tubing). I surely wouldn't use electrical tape!
Because the secondary side of the transformer was shorted together. The AC current at the secondary induces an AC current in the primary which was being measured by the isolation transformer.
He didn't remove the transformer, he removed the PCB (and rectifier) from the circuit. Electricity goes in through the back where it gets tapped off somewhere to operate some of the circuitry on the board (probably some low voltage devices like the fan and stuff) and forward to the primary of the transformer, which then goes through to the rectifier on the PCB. The rectifier was damaged so detaching the secondary removed the short and removed the current. Probably confusing is the fact that the transformer is near the front of the unit and not near the back, where it would be in a block diagram.
Hey i have like 3 pc power supplies and when ever i connect then to the ac putlet they tends to give me a shock and energies all the outer conductive components connected to it. Can you pls tell me whats going on ? (My house isnt grounded and it only happens with the pc powersupplies)
I just don't think that method was going to work what I thought you would do is alter the circuit to feed it 300ma at full brightness. It should have been less expensive than the $90 one. But hey you got a brand new one which just as easy might not happen. The one you got could easily have been just like the one you burnt. But all is well my lucky proff.
Just could try to increase filament current while running, instead of "burning up", but then it would age even faster. I've did that for K2000 DMM : xdevs.com/fix/kei2000/#vfd_rejuv
Having such a high level of laboratory instruments is way far from simple electronics repair shops or available to everyone.More scientific and research.
Electrocution is death caused by electric shock, electric current passing through the body. The word is derived from "electro" and "execution", but it is also used for accidental death.
Justin Bell, next time you copy the definition from wikipedia maybe also read the next sentence. You'll find that it doesn't necessarily imply death. You pedants take the fun out of everything.
Oh how this reminds me of the article by Catherine Mohr: code.likeagirl.io/making-while-female-df4100658c13 "Often, I am informed that a tool like that is only “really needed” if you have [insert expertise level here], so I would be better off getting something else. Then there is the Mr. Hyde version of talking about the tool which is equally sexist, and more plainly aggressive. It comes as a, “What are you making with that?” delivered in a tone and manner distinctly pitched to express not-so-polite disbelief and more than a little disdain."
The Signal Path, Your methodology is obscure to me, as a repair strategy. Knowing failure modes is a help and you showed no sensitivity to that part of the problem. While you do your work, you never show the part which matters to most people... the act of DOING the repair. It's as if you "forget" the viewer and only show what matters to you. Oooops!
Your attempt to restore the VFD reminded me of the old CRT rejuvenator that we used to use in the TV repair shop that I worked at in the late 1970s.
Still have one of those lying around somewhere :-)
Your new microphone does wonders to your voice.
Loved that introduction, it was purrrrrrrrrrfect. Great job on the repair. I have tried that over current on those types of displays before. Never worked for me.
Nice result which was inspected and approved by your cat at the end. Looking forward to your mentioned up coming instruments....
Yay Pooch! I always have to rewind and show my wife when Pooch makes a cameo!
Generally in my experience: overall dim means oxidization, and difference between characters means aged phosphor.
Note that "burning off" oxidization only works well when there is enough unoxidized getter metal inside the tube.
Glad it was a nice and easy repair for a change! Not sure if it effects this generation of HP gear as much, but I'd replace those yellow Rifa brand class X and Y mains caps any time I see them. Had two HP instruments get very sticky and smelly on the inside from where they exploded!
Minifig666, he won't even reply to common sense. So, don't even try and help him out.
I tried that same method for the VFD in my 34401A DMM with pretty much the same result (didn't manage to burn up the filament, though!). Your side-by-side comparison with the new VFD makes it quite apparent that the issue is with the phosphor and not the filament. Funny how so many HP/Agilent products from this era have this issue, yet all the VFD clocks in appliances around my house still look reasonably bright despite being on 24/7 for the last 10-20+ years.
I wonder what the science is behind the failure. Like is the phosphor depleted, or has it been poisoned and coated, because if it's the latter maybe reversing the current. They remove chrome plating by reversing the polarity.
I have a stereo that's at least 20, if not 30, years old, running 24/7. Its VFD is still easily visible in daylight, although it has slightly darker bands right under the filaments (so it's failure will be burning out the phosphor, not oxidation on the filaments). Maybe the HP devices are being driven harder to be brighter to be very visible in a lab environment (which should be a very bright workplace) and degrade faster because of that.
Sounds legit
Glowing the filaments only works if your filaments have been poisoned by DC bias. Every VFD I've dealt with specifies AC to the filaments to counteract this problem, I'd strongly suspect HP knew about this issue when designing this instrument. This unit had "phosphor fatigue" (easily identified by the phosphor segments looking dingy and inconsistent); there's no repair for that.
I've also experimented with rejuvenating VFD's and have found that getting the filaments to just barely glow for about 10 minutes seems to work the best. There is a point where you you can go to far, even with a faint glow. Also, just letting them operate with the most characters illuminated for a couple days sometimes brings them back. I haven't tried it but I think baking them in an oven around 100c for 24 hours would give favorable results. Great video!
I am from china,i find a job by learning your viedo,everyday
Nice. Especially the trial for regenerating the display.You can also do analogue, obviously!
Good Video glad to see another piece of gear saved from the landfill. :)
Awesomeness! Love a good dc supply repair, especially when you get to rerplace the rectifier AND the display :)
Nice cat ;D
Gotta love them, somehow. They are so nicely annoying most of the time and absolutely refuse to do what you want them to.
Love your repair videos. More suspense than a thriller! But you really need a brighter red nail polish on your right hand! ;)
excellent job. brilliant.
2:45 I was sure it's the rectifier. But I also expected a broken transistor.
21:25 too bad, I wished we could see if this procedure made any difference at all
22:31 Drawbacks of purchasing old equipment. Even if the part was already completely dead, the obscurity of it really hits the wallet.
It's always nice to watch your videos. Thanks! Well done on the repair
Hehe. Nice Intro. :) I thought you were gone for a while.
Nice video and good try on the VFD though.
Cryo-EM microscopes have a similar issue with residue accumulation on the capacitor plates, which end up forming spark gaps and shorts. Preventative maintenance procedures are to run it hot to prevent catastrophic failure. (I mean, the electron source itself is a pain to deal with hah!). At Caltech, the cleaning procedure is to effectively do what what Shahriar was doing... but at longer durations. This is consistent with vacuum tubes restoration that use (unthoriated? IIRC) tungsten -- 110% standard voltage @ 30 minutes to burn off any aggregate material.
Side-note, (no personal experience on this one..just remember someone mentioning it), on old fluorescent tubes (i.e. those ancient T5's), the single-ended ballasts would burn in unevenly. So much so that particulate from the electron source would be visible biased towards the emitting side (this is with a properly configured setup-- if other elements in the setup like your ballast are misconfigured/failing, then you have bigger problems than this). If you 180 them, you (in theory for sure, in practice, I believe as well) should be able to extend the mean time to failure
Also A+ Shahriar, great episode. This is definitely an "experiment' because you actually did experiment! This (personally) is an episode I would pay for, 10x over any sort of review.
(In my personal opinion, the best episodes are the in depth "tutorials on non linear.." and "tutorials on ___ filters" (episode 9,10), then the "proper usage of obscure stuff' (episode 26), teardowns of things like the Agilent optical stuff most of us don't tend to use in our day to day lives. Repair videos like this where you experiment are great as well.
Amazing I never knew you preferred that colour nail varnish.
21:51 AFAIK you're NOT supposed to get the filaments white hot but mild red. And given how hard it is to find replacements I think it's a good idea to test first if a lower current did the job.
In some cases you can increase the brightness just by increasing the negative voltage going to the display. HP tends to run them on -5 volts so you could increase that quite a bit and not have to bother with the filaments at all.
In another video is was told that you have to *slowly* turn down the filament voltage after cranking it up, to prevent the filament wires snapping.
I was crossing my fingers when you were increasing the current for those filaments. Too bad. (I would have done exactly the same thing!)
Great. Now I'm sitting in the dark.
I did a transformer rewind once for a similar power supply. It still works perfectly, so it is possible to disassemble the transformer and rewind it. :) just saying dont give up if the transformer is dead.
My thoughts exactly.
just need patience to rewind 200+ turns primary
For full proper function you need to short the sensing busses to the outputs also. I did not see the shorting bars installed.
At least this time you knew from the get-go that it was a problem with the power supply :o)
I have an old Casio calculator with one of those luminescent tubes and in poor light you can see the filament glow. Its been like that since I bought it new in 1974.
oh thank god... finally, a linear power supply...
I fixed one that would de-regulate above ~12volts. I replace the rectifiers, Pass FETS, and then the Gated-able Diodes (I understand that they are not exactly Diacs or triacs). Still it deregulated. Would you believe the whole problem was the crimping of a spade connector on the heavy secondary transformer wires? Instead of zero ohms from the XFMR to the PCB, it was much higher (maybe 1000 ohms), That explained why I could still see the proper A/C coming from that transformer tap, but there was no current behind it. I took the spade off, re-crimped and soldered it and it worked great after that.
Not bad for finding it the hazardous trash at work. I might of had maybe $20 in the parts I tried; that were not the problem.
I think in these Agilent power supplies rectifier bridge is most common problem. I had one with exactly same failure and I have seen one British guy's repair videoon TH-cam also with burned and cracked rectifier.
Can we a have Pooch special?
Increasing vfd heater voltage will restore brightness, but it burns out eventually...
Nice Repair. But this burning of the oxide doesn't make much sense to me. Isn't metal even more reactive when it is hot, so it is oxidising even faster? Anyways worth a try I guess. Keep up the good work.
+jolo0011 k You'd think. But that is not what happens. When you bring metal up to temperature the oxide burns off, and you are left with clean metal. I've done it many times with an oxy-acetylene torch on rusty hardware. Glowing metal up burns the rust away.
So, yet again the problem proves to be in the power supply :)
Nice nails Shariar
I wonder how hard it would be to reverse-engineer the VFD and make an LCD replacement. Definitely more than $90 worth of work, but could be a fun project. Sadly each device is different so there's no universal way to do this, otherwise such a project would be more useful.
Someone apparently did it: www.eevblog.com/forum/buysellwanted/hp-6632b-power-supply-replacement-oled-screen-(done)/
I've replaced an ancient LCD display in an old Fluke 8050A DMM with a graphical LCD display and STM32 micro that decoded the scanned display signals. It was a fun project..
Question... How do you get the shots where you're behind the camera without it being in your way? I'm trying to make similar videos but my camera is in my way and I find it really distracting. Thanks!
Here is a quote from an Itron data sheet on VFDs, "Since the lifetime of a VFD is dictated by the extent of evaporation of oxide materials coated onto the tungsten filament wires, it is critical that the filament voltage is supplied within the specified ratings." They made at least some of the HP VHDs. Do they actually coat the wire with material to enhance electron ejection and so burning it off would ruin the display? Or are they talking about oxides that form from use? It seems to me there may be a coating on the wire that you don't want to burn off which is why the display stopped working.
Really informative video, thank you so muck
Surprising amount of bodgewires for a relativelly simple instrument from reputable vendor.
Gery cool, Thank you for the Video(s)
Great hands :)
Oh my... The beginning is so fanny! LOL!
was this your cat speaking in the intro??
Great video!!!!! Also very nice PS for a reasonable investment of time and money. May I ask how much the broken instrument cost?
Thanks for the video. How do you record video when you are working on something that is in front of you? Is the camera above your head and you are ducking down?
What’s the function of isolation transformer ? It applies ac with more safety or something ?
Does E3632A uses single tap for each of its outputs over entire range, or does it switch taps at some point (i.e. 15V, on 0-30V range)? Update. Well, it looks it is not, I see no relays, and the one of the main transformer taps is going straight into rectifier, so it will operate from single tap over entire range, at least when manually selecting 30V range. I suspect another tap must be selected manually, to provide 15V range. And when using 14V, it will not switch automatically to 15V range.
One tail up for pooch!
Can you find the digital display and board for sale? Need to replace, Keysight?
electronics is black magic
where did they get those new old fluoruscent displays from? how do you usually control the brightness on these displays? could it have been repaired by just increasing voltage/amperage on that circuit?
I'm facing Unreg issue, with my E3634A
Observations :
1) Self Test pass . So that's a relief .
2) No errors reported.
3) OVP : 25V, OCP : 4A
4) Display Limit : 25V , 2A
5) Output On with 25V,7A Mode :
a) Setting 0V, 0A- Recorded (DMM) 42.62V
b) Output Off : Holds 42.01V (DMM) , takes close to 3-5min to 0V
6) Tried to change voltage and current setting on PS, But cannot change anything. DMM records 42.62V
Do you know how to fix it ?
Super InTeReStInG ! Thank you. 👍😂
Analog Agilent's FTW :)
Question, is there a similar 220v version of your isolation transformer (even if different brand) ?
If that transformer was shot, it would be a likely a short in the windings yeah ? Couldn't you test for continuity between taps to identify the failure point in the xfer, then use Kapton (or even electrical tape), rather than replacing the whole (heavy and expensive) xfer?
A Transformer is basically just a coil of wire, so a continuity measurement (wich measures DC-Resistance) would read a short circuit anyways (if the transformer is good or when some windings shortet together). If a transformer burns out (wich it would if the input fuse does not blow), it usually heats up from the inside outwards. That means that you have to unwrap a LOT of transformer wire to even get access to the fault. Also the melting coating on the wires tends to glue it all together. But if its a mechanical fault were for example the one end from the wire crosses the outside layer you could may be re-isolate that particular failure point with epoxy or kapton (-tubing). I surely wouldn't use electrical tape!
beautiful fingernail polish, too
Is the frame rate bad for anyone else? The video seemed quite jumpy in parts like the encoding was not quite right..
Nice nail polish
Nice repair 😀 How are those probe leads for your fluke exactly called ?
I always hate it when my rectumfryer melts inside.
👍👍
So why did removing the transformer make the high current draw go away, and yet there was nothing wrong with the transformer?
Because the secondary side of the transformer was shorted together. The AC current at the secondary induces an AC current in the primary which was being measured by the isolation transformer.
He didn't remove the transformer, he removed the PCB (and rectifier) from the circuit.
Electricity goes in through the back where it gets tapped off somewhere to operate some of the circuitry on the board (probably some low voltage devices like the fan and stuff) and forward to the primary of the transformer, which then goes through to the rectifier on the PCB. The rectifier was damaged so detaching the secondary removed the short and removed the current.
Probably confusing is the fact that the transformer is near the front of the unit and not near the back, where it would be in a block diagram.
Hey i have like 3 pc power supplies and when ever i connect then to the ac putlet they tends to give me a shock and energies all the outer conductive components connected to it. Can you pls tell me whats going on ? (My house isnt grounded and it only happens with the pc powersupplies)
How much the replacement display cost? I thought I heard $190, but then after I thought you said it cost only $9.
alfagulf think he said 90.
What is the purpose of the hatched trace pattern on the board? Is it connected to any electrical signal? Thanks
Looks like copper balancing to prevent bow and twist during manufacture.
Nice video nice cat
Help me ! Drop voltage
Cat Scan @24:50, still waiting on official results.
If the fuse is that black, there is a severe short to be expected !!!
I just don't think that method was going to work what I thought you would do is alter the circuit to feed it 300ma at full brightness. It should have been less expensive than the $90 one. But hey you got a brand new one which just as easy might not happen. The one you got could easily have been just like the one you burnt. But all is well my lucky proff.
Hahaha you (both) have humor!
How much do you pay for shipping from DigiKey?
rapsod - in North America it is free or $8 Fedex flat depending on total of the order.
Lucky bastards :) For my country is $120.00 hehehe
23:16 Is that you or your girlfriend?
no, that's his cat... she's got very nice nails :P
"Alexa, fix my display" o.O
Just could try to increase filament current while running, instead of "burning up", but then it would age even faster. I've did that for K2000 DMM : xdevs.com/fix/kei2000/#vfd_rejuv
Overheating (tube) filaments sounds not very clever. As for high power klystrons, this measure will severely degrade the kathode lifespan.
Having such a high level of laboratory instruments is way far from simple electronics repair shops or available to everyone.More scientific and research.
Have you ever accidentally electrocuted the cat while having something open and powered up like that?
Electrocution is death caused by electric shock, electric current passing through the body. The word is derived from "electro" and "execution", but it is also used for accidental death.
Clearly he hasn't because the cat is still alive.
Justin Bell, next time you copy the definition from wikipedia maybe also read the next sentence. You'll find that it doesn't necessarily imply death. You pedants take the fun out of everything.
23:16 heyyyyy u paint ur nails or wut lol :P
what the cat doing....
24:50 British Shorthair?
I'm fairly sure he's a Russian Blue. I have a fatter version of him :)
:)
hahah! i guess you should let your GF narrate your videos!
You need to SLOW DOWN. As the video progresses you go quicker and quicker - please SLOW
Wait, your girlfriend is interested in a power supply? Does she need it to charge her phone or something like that?
steve c She has a masters in EE.
Oh how this reminds me of the article by Catherine Mohr: code.likeagirl.io/making-while-female-df4100658c13
"Often, I am informed that a tool like that is only “really needed” if you have [insert expertise level here], so I would be better off getting something else. Then there is the Mr. Hyde version of talking about the tool which is equally sexist, and more plainly aggressive. It comes as a, “What are you making with that?” delivered in a tone and manner distinctly pitched to express not-so-polite disbelief and more than a little disdain."
The Signal Path, Your methodology is obscure to me, as a repair strategy. Knowing failure modes is a help and you showed no sensitivity to that part of the problem. While you do your work, you never show the part which matters to most people... the act of DOING the repair. It's as if you "forget" the viewer and only show what matters to you. Oooops!
I wish a girl would visit my lab aka my bedroom.
Yes, yes, we know that you have a girlfriend. now can we move on ? :)