Right, with you! Marco’s channel is a classic example of how expertise, presentation skills and humour can create entertainment that is off the scale of common measurement technology 😎 Thank you Marco - you are way more unique than the gear you work on!
Wooohoo, new ppm reps video :) I have fixed two of these 8508As with older boards and both had issues with ohm board and high voltage section. Yes! Awesome to see some proper INL charts instead of grafana craze :) Reps, gate arrays on 8508A are custom and not off the shelf. And their failure did happen to others, especially on ACV board.
Glad to see I'm not the only one employing my snaz to sniff out defects. People always laugh at me when I start literally sniffing around inside something they bring me for repair, but they don't seem to get that you not only can actually sniff out a burnt component, if you're experienced in doing it, you often also identify which type of component released its magic smoke. There's a difference in smell even between surface mount and pin through capacitors.
it's 4AM I should go to bed... Oh what's this? Marco released a video? What's another half hour on top of my 3 month sleep debt? At this rate, that's lost in the noise.
I loved this video! I only understood about four or five of every ten words you said. Not because of your English, your English is excellent. But because while I'm an electronics hobbyist, you are a maestro. Great video!
Didn't understand a lot of the words you said but I still enjoyed this video a lot. There's just something about electronics that I can't get enough of
@13:10 I bought a Vivitar Light Deck to chase traces. It has a very bright light, a 6.5 x 7.5 inch lens, changes colors, and you can link it to your phone. And it's cheap. I cut a piece of diffuser from an old tv to fit the lens. The whole thing is used as a base for my digital scope. It is perfect for shining through pc boards. The best part is it changes colors. Pc boards come in different colors. I have found out there are certain colors of light that make it easier to see through certain color pc boards. For instance, a yellow or blue colored light allows you to see through a green board way better than regular white light. I use green light for red pc boards, orange light for blue boards. It is almost cheating, it's like you have X-ray vision. Everything is clearer and much easier to see than with regular white light. Even the multi-layer boards I have worked on, the light shines right through. Of course, it won't shine through a ground plane.
@@reps I got part of the idea from sport-shooting glasses, usually yellow or orange tint. They help me see with better contrast and clarity. Real crisp and sharp outlines because certain colors are filtered out. The other part of the idea came from dentists who use orange tinted glasses for LED and laser treatments. The orange color filters out the blue light that is harmful to naked eyes, but still allow him to work. Ergo, use an orange light to better help see through a blue translucent material. And thanks for your reply and you are very welcome.
"You call that a moldymeter? THIS... is a moldymeter." An impressive piece of gear, absolutely a thing of beauty and a joy for ever. Proper respect for reverse-engineering and fixing this thing!
Soldering flux in the ear is definitely worse than ear wax on the PCB. Had to explain to a company nurse once how I blistered my right ear canal with a soldering iron. Hazard of working in very confined space requiring awkward positions. Avionics technician in general aviation manufacturing production flight test at the time.
Here I was thinking this would be like my “nightmare”-level Fluke 8505A. But no, a different nightmare. I think yours is a better one :-) Thanks for uploading, love your obsession with perfection.
Greetings from the Norwich site... Pronunciation hint from a local lad. Our city's name is pronounced Nor-rich, the w is silent. I'm fortunate enough to have a 8588A as a daily driver at the Norwich site. Well, as I repair them, and they are made on site, it would be rude not to. More than that, as you must understand, I am not allowed to divulge. Interesting to see your fault finding process. I have yet to operate on an 8508, but some of my colleagues do. At home I have a couple of Datrons, one 1065 and one 1061A. You're right, you can never have too many bench multimeters.
Norwich, England is pronounced as you say. FYI: The towns in Connecticut and Vermont that are named for it defend their W. (The one in Connecticut is on the River Thames - which is pronounced as it's spelt, believe it or not!)
You have an envious collection of measurement instruments. I used to work in a calibration lab that supplied services to the military and loved using this type of equipment. I trust your lab has environmental controls in place :)
It still fascinates me how big a measuring instrument can be, and still how accurate it CAN be even though some of them are more than 20-30 yrs old and still be reasonably accurate down to mV or nV
i took on a challenge of making an all analog circuit for one of my first ever devices, meant to teach myself and make a useful device. made a dual sensor automatic LED light. given i didnt know what i was doing when i started... it really didnt help that it was analog and that i didnt know how to separate multiple electrical loops/circuits on one device. but i do like analog stuff! cant believe these guys did it on such a big time device
I had to check to be sure. I still have a fully functional 8505A, I presume it is a predecessor to the 8508A. I bought it second hand about 20 years ago. I don't use it very often, I tend to use my 8840 or my 77 handheld mostly, but it is a great fallback if I need higher accuracy
About the GPIB connector: I know many scientists, including myself, who actually prefer these to modern interfaces like USB or even Ethernet. Ethernet is not so simple to use in a production environment with tight network security, and USB has the disadvantage that it needs drivers to work. So I usually buy high end instruments with GPIB or RS232, and then use adapters to interface with modern PCs. Might seem ugly, but it is a lot simpler if you have lots of instruments that require different versions of Labview drivers to interface a simple USB port.
I am not an electrical engineer by a long shot, but I always learn somthing new from these videos! Maybe I should get into building/repairing simple circuits.
didn't expect to see a discrete gilbert cell in this; i'm literary working on making a linear one myself; i'm not going to look at this part in the clip, as i don't want any spoilers; it's great fun trying to make it linear; the initial form only works with voltage swings lower than vt, so it's difficult to use in practice; one of the few books where i could find useful information is Analysis and Design of Analog Integrated Circuits, 5th Edition
Analog design sure is something else. I truly believe people came up up with digital becuse it is much analog is much more difficult to master, but it is superior in many aspects.
If you can tolerate a bit more input offset (or maybe an order of magnitude), the OPA192 family are e-trim parts (no zero-drift stuff) with +/-5uV typical offset, +/-50uV worst case from 0-85C. It can also take up to 36V between the rails, might be a good option for high source impedances in these kinds of projects!
When we do complicated repairs, working with flir camera is def one of the first methods, however, sometimes just going through component by component is actually faster in the long run. Normally you'll start with diode testing, but resistors can be tricky, specially when in parallell with other resistive elements. Much time is saved by just lifting one component at a time and measuring. Boring yes. Effective yes. Good work though, however, there might be some resistors "half broken" or out of spec somewhere that are missed............
I feel like Marco would be very happy if there was an open source CPU replacement for some of these meters, or at least some way to mod the existing firmware. Some of the missing features would be easy to code up in software.
I designed a custom 10000:1 voltage divider for a project, rated up to 40kV dc. I made a point of including a GDT and two ground terminals so cal labs had no excuse if fritzing their kit with excess CMV. My boss killed a Datron that way. It is hard to find cal labs who go that high with any precision.
Thanks for all your amazing videos. Would there be any chance you could take photos of your JBC tweezers stand board? I have the HT420 tweezers but not the stand. Trying to reverse engineer the little PCB board inside. Appears to have two diodes and resistors. I've got a recent post on eevblog asking for help here
If sent to the manufacturer for repair, you can bet that they would have said it's unrepairable. HP is bad for it, too, because they want to sell new equipment. Great job on the repair!
Mate, this is way above my head but I´d like to ask: how would You go about copying a one sided board? I fiddle around with an old Radford amplifier and a lot of traces came loose when introduced to heat after 50 years so I´d like to just copy the existing design. You work a lot with PcbWay- can I simply put the boards on a scanner and send them the scan to repoduce? Kind Regards
I believe KiCAD has tools for placing images, vectorizing them and transforming them into copper. If you get the scale perfect, it should work that way. Redrawing everything would of course be neater
Why is everybody so afraid of back EMF from relay coils? I tested a 1kg 10kW contactor AEG with 24 VDC coil. I let a 2N2222 drive the coil. No back EMF circuit. No problem. The LM 324 has a slow output slew rate 0.5V/us minimizing HF interference, and it is cheap.
Those two orange toroid looking things are really two different Stargates used for Calibration.. one of them links to the Soviet Stargate meter to transfer ppms.
