EEVblog

[@FranLab]

Yea - Fran's vintage gear troubleshooting step #1: Clean all contacts. :-)

[@deanedgington5275]

+Fran Blanche Good tip Fran.

[@chriswouse7713]

confirmed - last one I did I used a good amount of contact cleaner, good as new!

[@petersage5157]

Seriously, Dave. You didn't suspect an electromechanical fault immediately when you saw the ranges randomly come good while you were mashing buttons? I am disappoint. The 30KV discharge could have been a red herring, but it could easily have carbonized the contacts on that switch as well. Dave often says that Commandment #1 is "Thou shall test voltages." I'd say "Thou shall clean all contacts" is Commandment #0.

[@ConstantlyDamaged]

As a programmer, I am glad I am not the only one who spends hours looking for bugs only to find a bad input management.

[@BGBTech]

Darthane I spent a good deal of hours recently trying to debug an MSP430 interpreter/emulator after adding a direct-interpreter sub-mode (it would use a faster threaded-code/trace based decoder/interpreter executing from ROM, and a slower direct-interpreter for RAM where self-modifying code is more likely, and would otherwise require flushing the trace-cache). spent a long time (much of a day) trying to hunt for a bug in the actual interpreter logic. turns out it was a bug in how I had rigged up the test to force the direct interpreter to also run code in ROM, conflicting with the logic for passing control back to the trace-interpreter whenever ROM addresses were detected. made both places use a shared predicate function, so now I can force the direct interpreter simply by disabling the check for ROM addresses.

[@userPrehistoricman]

Brendan Bohannon Can agree. It's awful when you think your program is wrong, when it's actually the testing that is incorrect. I've been writing ROMs to test an emulator I'm making, and have gotten into all sorts of confusion based on my testing ROM being incorrect. Plus the documentation for this stuff is awful.

[@BGBTech]

Prehistoricman yeah. generally spent a fair bit of effort trying to figure out things which were poorly explained in the documentation. I wrote an emulator for the chips partly as I am using them in some projects (mostly the MSP430G2xxx DIP14 and DIP20 chips). I was not very impressed with the existing emulators I had tried, which seemingly couldn't emulate the chips in real time, and didn't have much in the line of being able to log/analyze output or simulate external peripheral hardware. so, I threw together an emulator, thus far have it running around 90 MIPS on my PC (a fair bit faster than the real HW), and am working on integrating it with a real-time/interactive electronics simulator of mine (sucks hard at analog components though). the idea is basically to be able to drop an MSP chip into the simulation and connect up peripherals (and have a ok idea how it will behave). another possible use is supplying a ROM image and some inputs (high/low or a logical pin voltage), and then logging the pin outputs at a fixed logical frequency (probably 48kHz). I have done similar for code I have targeting ARM devices, where generally I use WAV for recording GPIO outputs (though, generally, this has been by building the code on a PC and using stubs to fake the external hardware).

[@userPrehistoricman]

Brendan Bohannon Sounds like you have some big tasks on hand!

[@BGBTech]

Prehistoricman not particularly. I threw together the interpreter over a few days, as the MSP430 is actually a fairly small/simple ISA vs some of the other things I have written interpreters for. the electronics simulator has been on/off effort for a few months, but is mostly held back some by me being "not really all that sure what I am doing" on the math front. I discovered fairly quickly on that Ohm's Law by itself doesn't apply so good to simulation (applying it basically requires being able to look at a circuit top-down and apply some amount of intuition, but it doesn't hold up so well if applied bottom-up with each component acting independently). so, early on I had ended up treating volts and ohms as the fundamental units, and trying to infer everything else from volts and ohms, didn't work well (and amps doesn't hold up well in use, but with just volts and ohms, you get amps coming out of nowhere). considered now trying to rework it to a system based on volts, ohms, and potential watts (where Pi=Pw/V and I

[@DougEStile-gj7wy]

Before I retired I worked as a bench technician for a small electronics manufacturer, and we used several Keithleys similar to this one, mainly because the boss was too cheap to get us newer DMM's. They worked well, and I liked that the displays were so easy to read. Seeing this one and hearing the switches click brought back some memories. Cheers!

[@greengrayradio1394]

Nice as always, Dave! I spray those switches from the rear, they are open there, and the cleaner can penetrate into the contacts. Sometimes it's easier to pull the knobs off and spray from the front. "Torture" all the switches afterwards with repeated pushes to do a good cleaning

[@rbarkoch]

Even without a crazy interesting issue, these repair videos are great and give a great perspective into the design of the product, often times even more than a regular teardown. Keep them coming!

[@TonyKD8RTT]

Dave, just want to say I appreciate this type of video. I know it's a lot of work to do repair videos, but I really enjoy them!

[@BillyNoMate]

It doesn't matter what the outcome of these repair videos, they are a great troubleshooting resource. (y)

[@DoItYourselfMusician]

Who else was screaming "Clean the switches Dave!" for like the first 40 minutes? Pro tip, you can drill a small hole in the top of those gang switches to get cleaner in them.

[@RandomUser2401]

do you know why each of these switches has a different amount of a buttload of contacts?

[@SaturnV2000]

Important also to note - Yes, "wiggle" (wig for short) is a measurable quantity . . . the physical displacement of an electrical conductor (wires in particular). Follows standard notation . . . 1000 milliwiggles (milliwigs) = 1 wiggle 1000 wigs = 1 kilowig

[@fagear]

Hi Dave. From 1:35 and I could not think of anything except those switches... They look very similar to USSR "П2К" series that are known to have issues with wear and oxidation. I didn't find any video about repairing them, so I've shot my own (/watch?v=lieYhz3ICo8) Voice is Russian (of course, I am in Russia), but I've made English subtitles for the video. Probably after you watch it you can refresh all those switches and be confident in that DMM. BTW, in Russia we use those "funny plugs" also. We call them "european plugs". ;)

[@CrucialSpeaks]

clean switches.. Blue stuff if you have it, polishes too. GREAT VIDEOS! from a 45+ year component level technician with 48 certifications and vice president of CESDA (sub of NESDA) in 1980- 1983!!

[@littlebushfarm]

Dave, my son is just getting started into electronics (he's only 8 but we're making progress), at the moment he's got a $6 meter from Jaycar!!!! It would make his day to be the proud owner of this...I've got a sister in Melbourne that is heading back to NZ soon so it makes postage simpler. Cheers edit:Ah, too late...such is life!

[@jerryfox3731]

I learn from every video you make. Old or new. Whether it jump at you or not. Because that is real life. Thanks for all you do. keep up the great work.

[@wheelitzr2]

That was a perfect example of how something small like the blown resistor can really narrow your way of thinking and make it difficult to diagnose something because your brain is hung up on that one part. Excellent video I'm glad you put all that footage in.

[@davidcasper312]

grateful for blokes like you Dave.

[@MrOffizier]

If I have to fix something I go strictly through my list: 1) Check for mechanical issues 2) Check PSU (eg voltages) 3) Check for bad caps/burnt objects (you can take a quick look before step 1 and 2) 4) Check the rest No. 1 fault -> mechanical (Ok, if you repair monitors/tvs, it's like always the caps)

[@bigjohnsona2]

Hi Dave never commented before but just wanted to say i LOVE repair videos, i love how you explain the processes even if you don't fix them and would love to see more as i think you can learn so much from fixing broken stuff, I'm not an engineer just a hobbyist but i learn so much from these type of videos. Makes me wanna fix something

[@ciprianwinerElectronicManiac]

I was screaming "Spray those contacts" at the beginning of the video. Glad that you've found the problem and fix it. Cheers :)

[@reallyniceaudio]

I just fixed my 179A which had the same fault. If you turn the unit so the front is facing down you will notice your can squirt down a whole in the back of the switch! I then did a transfer cal from my 2015 and have managed to get it to match perfectly. I am so pleased with it it has replaced my silly isotech idm 203 as the screen on the 179A is amazing!!

[@Tjita1]

That's a European Schuko plug. We use 230 V in Europe. :)

[@boshypatry]

Tjita1 German tecnology :D

[@QlueDuPlessis]

Tjita1 Yeah, I noticed that too.

[@Tjita1]

AlainG80 It's used in several parts of Europe (here in Sweden among others), and it's called Schuko, although the real name is CEE 7/4. I should know, since every single grounded doohickey here in Sweden uses it.

[@Tjita1]

Yeah, I located it again in the video and checked, it's definately a Schuko.

[@AlainG80]

Tjita1​ Indeed, the french ground has been blocked by a bar @kzbin.info/www/bejne/oZWml3SIZZt6m6sm37s I withdraw my comment.

[@direchannelstream9278]

ive exactly the same problem with the same model. sprayed the contacts now with contact cleaner and let em dry overnight. (next day) well and now after 8h drying its working perfecty. thank you dave. you rescued at least one more unit with this video;-)

[@KX36]

I was shouting at the screen that it was the ganged switches from right at the beginning of the video when it was failing and then coming good almost only when you pushed a button. I think that's because I'm watching and not doing so I could pay more attention to things like that. It helps to troubleshoot with someone else. I really didn't expect to be right though because of the counting up numbers I didn't know how a dodgy switch could do that until you explained at the end. I then thought it was going to be the integrator, especially when the zapped resistor was in the vicinity of the ADC testpoints. When you looked at the schematic showing the blown resistor in circuit and I saw the ohms switch above it I again suspected the switches. I'm right about these things so rarely that I'll be walking around with a smug smile all day.

[@K1ZEK]

Enjoy your videos. It is nice of you to think of the kids coming up in electronics, it will come back to you 100 times over. God Bless 73 Leo K!ZEK USA

[@managementrights6037]

Perfect at 36:20 David reveals the fault in the physical contactor, inspection and diagnostic technique plus experience is good

[@JIMO415]

Dave, Great videos and your humor is fantastic. This one brings back memories. In 1992 I came out of school and worked in a cal lab for 2 years and I saw quite a few of these. Back then I was cleaning some of the switches on these! I used to "shoot 'em in the back side".... that is; the end of the switch is open to spray into. In the 310 comments, someone probably already mentioned that. I dislike intermittent symptoms arrrrg! Also, the mains potential fuse, well that memory is a bad one. That pin connector directly adjacent to the fuse...well... don't bridge that leftmost exposed pin while prying the fuse with a screwdriver!! IIRC that left pin is the supply rail to all the I.C's. Don't ask how I know. Let's just say audible magic smoke. Thank you from NJ and enjoy, Jim

[@T2D.SteveArcs]

I've had this loads of times with old scopes, given the information you received with this I would have opened her up straight away aswel, voltages, silicon, flex the board, poke around, re-seat the ICs and so on 🤷‍♂️.. sometimes its better with no prior information 😅 as soon as I saw the A/D was working I knew you would get it going, bit of a surprise to see the separate integrator ic like that.. good video anyway mate 😎👍 hope it found a good home to live out its twilight years

[@pauldickhoff3594]

My keithley had exactly the same issues. I had a bit of a runaround with seemingly bad caps, but eventually the gang switches had multiple cracked solderingjoints. I should have expected that from switches that have been banged and abused for some thirty years. Bit of work but a great 5 euro fleamarket deal.

[@pedromms8908]

David should get a raise for saving you a lot of "debuging" time!

[@shaymazor4925]

***** yes 1 cent more per hour

[@Mythricia1988]

Ooh, I just sat down with some dinner and felt like some EEVBlog would be good right now, figured I'd dig up some old video I hadn't seen... But nope, this was just here!

[@TheDavelectronic]

Give Dave 2 some credit for finding the mechanical issue !

[@wattage]

Great video Dave. I really enjoy your troubleshooting and repair videos. Always educational and entertaining.

[@zx8401ztv]

Dave, the 666 confusion is perhaps because you didnt leave the tp1-tp2 short in place. Right from the start i saw dicky switches, im really supprised you ignored them lol. The back socket did kill the psu, nothing else, and after it was dead the owner must have stored it in a slightly damp place, thats why the switches played up. Cracking video though :-D :-D

[@EEVblog]

zx8401ztv Ah, ok, could be the short, that makes sense. The switches did not seem that dicky to me to begin with, not enough to be important, I did more playing off camera various times and there were things that pointed away from dicky switches. Only once analysed did the dicky switches become fairly apparent as the main culprit.

[@zx8401ztv]

EEVblog I have an old fluke 8050a that becomes silly if its not used for a while, one day i will desolder all the switches and frighten them with a clean lol. Also i found parts of the front plastic panel and pcb became slightly conductive, ive never seen plastic do that before, odd that lol :-D

[@zx8401ztv]

Stuart Wilson lol yep im sure your right :-D Old chinese proverb says: "Check the simple before the complex, but do the reverse when there is a "D" in the week" :o)

[@jusb1066]

zx8401ztv All them switches had holes in the end, an easy place to squirt some stuff, esp if you tilt it with face down, well worth doing all them just to make sure, plus tidy up the inside (maybe that bridge rectifier, blown resistor just because etc...), its still a decent bench meter

[@zx8401ztv]

jusb1066 Yes it is a nice multimeter :-D and far more accurate than most people need for basic electronic repairs, the two chip adc just reminds me of the icl7106 thats used in just about every cheap multimeter in the past, they work really well with the correct parts added :-D The quality of the attenuator resistors and reference voltage is the part that matters the most, spot on dc voltage and excellent ohms ranges. I have an old fluke 8050a i use for a reference to set my cheap meters by, its old as the hills but still usefull :-D

[@SaturnV2000]

Good observations Dave2! Good presentation Dave1! BRILLIANT! Even though it turned out to be a mechanical issue, your approach was very methodical and a very valuable lesson. You were hoping for a basic defective component/replace component scenario, but turned into (very typical) the sort of things repair techs encounter every day . . . easy to get sidetracked when troubleshooting intermittents. And that -1.2V? Probably a typo . . . a bonus lesson - So for the students out there, this is where your skill and knowledge can get put to the test - have to analyze things carefully. So this video is absolutely a win. Thumbs up!

[@EEVblog]

SaturnV2000 The -1.2V is (now) obviously only valid with TP1 and TP2 still shorted as per a previous step. I should have twigged to that.

[@SaturnV2000]

EEVblog Yeah, I see that now . . .

[@helmetdump]

To get contact cleaner into those switches, spray contact cleaner into the openings at the end of the switches. Those switches sometimes had silver plated pins that oxidize with time making poor contact.

[@Regular6782]

Thanks for the video Dave! I have an obesession with Fluke meters too, I have been collecting them, I use them quite a lot at work. So I don't need another, but just wanted to say thanks for the videos mate.

[@JustSomeGuy1967]

Do more repairs Dave. Trying to learn this stuff and so far failed at a tv repair...actually made it worse...depressing!

[@blackstar2008]

Mark Jordan been there done that

[@zwz.zdenek]

Mark Jordan TVs tend to be harder than most things. Try with simpler appliances first.

[@JustSomeGuy1967]

Was really a bummer...thought I had it figured out...installed the new parts and flipped it on and crap picture...it's ow in the dumpster. Think your right...gunna try some easier stuff.

[@phano6385]

Mark Jordan Hey, failed projects are the bread and butter of learning. I understand what I'm working on a little bit better if my first attempt goes up in flames!

[@DjResR]

Interesting fuse at 2:34. Resistor and a spring soldered together with low melt point solder, can't see this every day. Awesome. The plug is same we use in Estonia on 230V 50Hz so it's identical voltage/frequency as you have there in Australia. Those gang switches are notorious for dodgy contacts, even soviet ones were prone to fail like this. And it's a nightmare to get those switches back together as most likely the moving wipers are loose in a gap inside the gang.

[@rcboy147]

Hey Dave, I'm 16 in Melbourne, Australia and actually only have one multimeter that I bought when I was about 10. Its served me well over the years but I'm getting back into electronics because of you and a Tafe course that I finished. It would be really nice to have more or less precision meter around. I have been focused in the computer industry for ages but I am closing the gap in between my computers and networking and my electronics (Thanks to my raspberry pi). Anyway I mostly lurk on youtube and don't comment very much and sometimes have a look through the forums. Love your videos, keep up the work :D

[@Teukka72]

For future reference, those ganged switches can sometimes have issues with the solders to a PCB - basically, the mechanical action can cause solders which were marginal to begin with to go bad. Nothing worse than inspection of the pads and reflow as necessary.

[@davidcasper312]

Dave, those open to air switches needed attention first. Don't usually do this, but detail and order of repair counts in old stuff. Still Love my Aussie!!

[@BMRStudio]

Hehe :) Thats why I start allways with switches, pots, connectors in any repair of old gear. 90% the problem disapier :) Thats why I like the old gears. Lot of manual controll what You can clean, repair, replace. Nice video. Thx Dave's!

[@noderix]

Still a great video because I watched it to the end. This would be a good start on my bench, only have a Fluke 12 from years ago, no current measuring! If Rajesh passes I would love to give it a home in Melbourne. Thanks!

[@pocoapoco2]

I've actually been able to fix a few circuit boards in the past by giving them a bath with dishwashing soap followed up with a very thorough rinse in distilled water and jet dry.

[@NeverFinishAnythi]

Aww these videos scratch my thorough troubleshooting itch.

[@tardate]

This inspired me take a second look at a dicky DMM of mine (almost in the bin - you are right: test equipment you can't trust is no good at all). The intermittent, capacitive-like behaviour sounded familiar. Whaddya know? Quick clean of the switch contacts (a rotary dial that presses it's contacts directly to PCB traces) and it's all good again. Thanks, saved me a few bucks!

[@jon123423]

Old is always dust, i was fooled once in an old equipment, but i took the easy path first clean, clean and clean and All was working like knew.

[@TheEPROM9]

I would say that it did not suffer the usual curse. It was a nice mind bending problem that tested the grey matter.

[@cemx86]

About cleaning those range switches - if you can get the front escutcheon off, spray the cleaner into the front of each switch. Ohhh for the days of liquid freon!

[@smadge1]

Hi Dave, great video, I enjoyed watching you troubleshoot the issue. I'm in Brisbane, trying to get a start in the electronics hobby. I have 2 "digitech" brand DMMs, and I'd love something Keithly branded, especially one repaired by yourself, happy to pay postage too.

[@thomasbaumann694]

I would also suggest to just resolider the mechanical parts - here the switches. No need to take them apart, just heat up each pin one by one. This fixes also most of problems, because mechanical stress is released on the pins, If you hear a little crack during this you'll know there was a force where it should haven't been. Not an ultimate "this fixes all" solution, but hey, it worked several times for me.

[@Thetubeamper]

I do believe the best way to clean those switches are from the back, you can actually see movement at the back of them when you push the switches, so the backs are open.

[@spiros1994]

Nice one! I learn much from these type of videos. Thank you Dave! I guess the least I can do (due to capital controls and economic reasons here) is to leave a like and a share.

[@thomasboos2470]

hi dave, this is one of the videos I like, seeing everyone struggles with such issues :) btw. the mains plug I would say its a typical "Schuko" connector (CEE 7/4) used in germany, with 240V.

[@EEVblog]

***** Yeah, I could have just edited out all the garden path testing and made it look like I magically found the switches, but that's not the least bit interesting. Warts and all is far more interesting.

[@sdp8483]

I have an HP DMM with a similar problem. I will have to see if I can use some of that lubricant on the switches. I cleaned them with IPA when I first got it but I did not know that that kind of lubricant existed. Thanks for the repair, good information as always.

[@KozmykJ]

Just bought one of these on eBay, Keithley 179, thought I'd check and see what Sir Dave of Jones, Lord EEVBlog had to say on them. Mine has yet to arrive. Me being an old repairer of old stuff I go for the Servisol 10 every time for starters, but then I'm not usually filming the proceedings... Old guitars, amps, synths main problems come from pots, switches and sockets though I DO have a 66 Tele here that needs a pickup rewind.... that'll be fun. Can you ever have too many meters? 3 DMMs (soon to be 4 when the EEVblog BM235 arrives 😉) 90s, 00s & 10s 3 analogue meters - 90s (including 2 old AVOs Mk8 & Mk7 both of which need servicing - 70s & 50s) Fluke 8010A Bench Meter - 70s

[@hernancoronel]

Hey Dave if you want a difficult electronic fix like you at 52:00 why don’t you go back to your HP3567A DSA and do the final part 5 and fix it! Thanks for the great content!

[@Robert.K]

Hi. You're supposed to spray the contact cleaner in from the rear of the switches, not the top, while operating them. Remember: you have to wait until it's dry as a dead dingo's donger, before you turn it on again.

[@bitteroldskunk]

Just goes to show, sometimes the vintage equipment isn't as bad as most think. They built them to last as long as you don't do something foolish with them an sometimes all you need is a little love and care for this type of equipment. But I do see a need for newer equipment and there is nothing wrong with that.

[@rachelmaxwell4936]

I was hoping this episode would have been about the electronics in the Boeing 777 series.

[@iPelaaja1]

Tear down of a Boeing 777 :)

[@markybyeah]

You are under FBI watch for that.

[@userPrehistoricman]

iPelaaja1 I would have preferred a "shootout" video.

[@spinningquad8700]

I'd love the meter Dave. I'm a student in Brisbane who doesn't have a decent meter. Thanks for the great videos. Greg

[@EEVblog]

Spinning Quad Sorry, already gone.

[@spinningquad8700]

EEVblog thanks anyway. Love the blog.

[@AndyMcBlane]

Damn that meter looks awesome, love the vintage look to it. Just going my first Engineering unit at uni in Sydney at the moment. Would love to own it!

[@majodio]

This kind of video is very educational for me. Thank you!

[@TheHunChem]

16:30 I think you need a priest and not an engineer (Let me add: This is what happens to your 777th video when you leave out the 666th episode.)

[@tubical71]

HunChem exorzist.....;)

[@gl1500ctv]

Yeah, at 40:15 checking U14 at 0.666v... Dave, your meter is possessed. ;)

[@gravity7438]

There are units of wiggles, Hertz. Maybe even the Reynolds number, if the party gets wild enough. Main thing you might suspect with a flaky reading like that is an opamp or capacitor error. The offset compensation can get hit by esd pretty nicely in an opamp. Then trace related micro stuff like contacts. Might not have even been pitted, maybe just dust falling through those open holes for years if contact cleaner fixed it. What could have saved you some time was perhaps considering that if the ADC itself was out, you'd probably just be getting all sorts of garbage on the display, rather than intermittent success.

[@marceltimmers1290]

Hi mate. Tough I have only little knowledge, I did suspect the switches right away. I did not think of the contact cleaner however. This must be a good one, because we used to call it, heroine for electronic. If you use it once, you have to keep using it. Marcel.

[@davidhoekje7842]

When troubleshooting starts to not make sense I try to remember the phrase "check your premise". We approach a problem with an inference or assumption in good faith and sometimes forget to question that. I would not have guessed the switches, though it did seem you were getting some effect from playing with the leads.

[@zaphodtoasty9208]

Hooray for dave2.

[@ArumesYT]

Too bad Dave (1) tries to take credit for it "as I uh, you know, originally sortof uh started to suspect there"... He does know a lot of stuff, I'm learning a lot here, but his character sucks big time.

[@gblargg]

Those switches looked questionable from the beginning as there are so many damn terminals, and thus rolls of the die for mechanical failure. That's one of my prime concerns when using a multimeter, because they all tend to have lots of contacts like that that can fail and ruin readings. Reminds me of the time I was troubleshooting an LED backlight driver board for an LCD monitor and kept having the LED strings shut down like there was a failt. After too many hours, I traced the problem to the vias in the PCB developing hundreds of ohms of resistance when the PCB started to heat up. I added thin jumper wires through dozens of the vias and the monitor has worked flawlessly since. Total mechanical failure but I went down the path of doubting the LED strings in the panel, the LED driver chip, the capacitors, etc. (and learning a lot about LED drivers, which made it at least educational).

[@TheSoundtec]

My electronics teacher always said , make sure its plugged in.. Ya the simple things 1st.

[@jonka1]

Dave. Make a new mantra. "Thou shall check the voltages and apply contact cleaner to the switches" before looking any further.

[@naknakacknak]

I've taken a battery drill and a small drill and drilled a small hole slightly larger than the stem of the contact cleaner in an area of the switch that is away from the internal mechanism to allow flooding the switch with contact cleaner. That seems to work ok, but you have to be very careful.

[@КириллРагузин-р9в]

The first thing I would do is I would replaced the burnt resistor just to be sure. Even if the little thing is still working. And the switches like this are pretty much always start to play some funny business after a couple of decades. I consider there are two main types of combined rocker switches: those who make a good solid click like some old Soviet-made ones or some stuff found in an old Tektronix gear and those who have a more soft and ligth action like the like in most old made in Japan stuff. The seccond type ones are pretty much just pieces of crap.

[@zwz.zdenek]

Кирилл Рагузин These Isostat switches have silver-plated contacts and leads combined in one piece. Silver blackens and there's your problem. They also usually have some grease in them that can react with the metal making it worse.

[@xDevscom_EE]

Had similar issues with Keithley 2000 front/rear switch. End up desoldering it, disassembling and breaking :) After replacement - rock stable readings as well. Also should have used Keithley's SMU u have to generate volts, would look in line with Keithley video theme :D Just 5c :)

[@noisevector]

Funny plugs :). They are normal here in the Netherlands.

[@EEVblog]

noise vector :: dj tremor :: dusp2k Doesn't make them any less funny to an Aussie.

[@drkastenbrot]

In germany too

[@noisevector]

EEVblog the same applies to us for your plugs.

[@Germanwtb]

EEVblog they are 230V, normally

[@marcus_w0]

EEVblog As we think, yours is funny ;) btw. thse Plugs are used for 240V systems - its not your so called Yankee-Plug

[@SpacedHarrier]

The AC in my car kept turning itself off and on, but the blower fan would stay on. Imagine my surprise when I found out the fan dial contacts were corroded, and the AC switch was an entirely separate contact on the same dial.

[@TzOk]

Back of the switches is usually open, you may apply the contact spray by there.

[@dbbew]

blowed resistor and bodged switch i watched for 50 minutes thats what i got and interesting but i donno.i did enjoy you naming the parts as you tested that really helps on wanting to test my own circuits.AAA++++

[@DJignyte]

Great stuff! Thoroughly enjoyed it.

[@wa4aos]

DeOxit is your friend Dave!! Golden Rules: 1) clean switches 2) don't waste an hour farting around measuring stuff until you do Golden Rule 1 3) If you do waste and hour farting around before doing Golden Rule 1, don't post a video of your apparent lack of respect for Golden Rule 1 for everyone to laugh at. 4) eyeball for obvious issues like burnt stuff and then decide of it's worth farting with some more. Either toss or rob parts and toss. Or if it deserves another fart or two, goto, rule 5. 5) Look for docs. if doc's can't be had, probably time to toss it then fast forward to rule 8 6) If you find docs, start measuring stuff in the most obvious area. Ie, don't troubleshoot the tailpipe if a headlamp is out. 7) If something is off ie, Voltage, freq, amplitude etc, look for fault, fart some more and call it a day. 8) If you ain't fixed it by now, eat some beans, fart around another hour and either fix or toss the thing. Then buy another, "working last time I used it." piece of crap on ePay and go to rule 1.

[@TestECull]

And yet we never did replace that blown resistor. I bet that Pin 14 voltage would come good if you did that.

[@chuckpatten7855]

The switches appear to be silver plated from the appearance of the exposed terminals. Pitting is unlikely but corrosion of the silver is likely. Try a couple of hundred transitions of each pushbutton and you may get lucky...

[@TKomoski]

Dave I don't understand why you didn't turn the board over and look at the solder joints. You can bet your ass you have a cold solder joint. Constant pushing of the switch can lead to joint failure. Turn the board over and reflow the joints Dave. Cheers

[@engjds]

Moral of this tale is, ALWAYS suspect mechanical parts FIRST, especially on intimiitant faults, soon as it faulted when the front panel was bouncing about I was screaming at the screen "Switches"!!

[@kibi15]

Surely one of your Tek 24xx 'scopes will provide some good electronics repair content for a future video.

[@XtianApi]

We don't all speak like that in the US, lol. Love the channel

[@trebushett2079]

Your comment as an electronic engineer "ah, bloody mechanical crap" contrast well with my occasional comment, as a mech engineer, "ah, bloody electronics crap" :)

[@pufero1]

+EEVblog You clean bad the swich they can clean from back with the meter vertically soo the clean flow and get the dust and dirt

[@nightmarejr]

What happened to the good old smack? Old equipments have a temper and need a reminder of who's in charge.

[@EEVblog]

nightmarejr I gave it several good smacks and got nothing.

[@THEtechknight]

EEVblog You didnt try the BFH.

[@mahill2006]

EEVblog hit it harder?

[@robertmalsbury8477]

Realty Dave? I would have checked the switches First. As a retired broadcast engineer, I learned a long time ago that 90% of intermittent problems are mechanical. The good news is that I didn't post the video as I am sure Murphy would have paid me a visit too. Where is your No BOZOS sticker?

[@losttwo1]

I would have thought you needed to keep TP1 and TP2 shorted, in order to get the correct voltage on U105 Pin 14.

[@Bbogita]

EEVblog I know you said only people in Australia should apply, but I'd be happy to pay postage to the US if you haven't given meter away yet. I'm 15 and have a small electronics lab set up. I only have one DMM and no bench top ones at all. My electronics skills have landed me a job at a marine electronics repair center making good money. A ton of what I have learned came from you and I would even consider you one of my idols. I even applied for David2's job when you were accepting apps full well knowing US ≠ Australia :) Alright, enough buttering up :) if you haven't already given it to @PRITHIV RAJU I'd love it too.

[@rachelmaxwell4936]

Also that funny plug is standard across most of europe including scandinavia, I'm in Norway. I would have called the British safety plug to be more funny looking. Any chance of getting a video (maybe a bit boring) on various plugs around the world. Maybe people should send you some samples xD.

[@yamum248]

Hey Dave, I'm an 18 year old computer eng student at UNSW. I'm setting up a home lab and would really appreciate such a meter. I can also pick up if that is more convenient for you. Thanks for making such awesome videos (makes it hard to sit through 1st year introduction to elec eng lectures). Cheers, Jack.

[@FoxMccloud42]

the powerplug is a european plug used in germany, poland and co.

[@robfletcher8762]

If the oil is conductive, it might fill in the pitting on the contacts for a few operations but eventually would drain off right? I've fixed a few switches with major pitting(brake light switches in cars) by using some 1000 grit paper and getting the 2 bits touching properly. It was working when I sold it, anyway.

[@Ihavetruth22]

oil not conductive

[@paulbadenhorst2981]

Did you check for cracked solder joints under the switches? That could have the same effects.

[@Vandwo]

Well this reminds me our washing machine that i troubleshooted the controller board for few days and I obviously refused the version that the set position switch could be faulty. Anyway it turned out to be worn contact plates inside that dmn multi position switch and the really worst part was that sometimes it provide good contact, sometimes not.. I was getting really confused back there..

[@hyperluminalreality1]

I own two 179A units. RANT... A multiple contact input routing switch array that is 35 years old and he completely overlooks it?!? Not to be a dick, but this should have been a 10 minute video, tops. I was kind of amazed that Dave did not perceive the switch contacts being intermittent when he was playing with it at the very beginning. He looked right past the gang switches and into the logic because of the charging effect seen. He did not even wiggle them for "wonkyness" right off. TRICKED. Always wiggle for wonkyness right off....... Glad I watched up to 10 minutes, got frustrated and read some comments, then skipped to about 50 minutes in. Thanks anyway Dave...

[@widecast]

The path for the fluid is through the end of the switch. Turn the unit on it’s face and squirt down the end of the switch. Obvious!

[@jlaudio982]

dirty oxidized or burnt contacts. DeoxIT works great!!!