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No problem, building rockets seems like a load of fun. I hope to start building my own some day!

TURN UP YOUR HEARING-AID.

I actually have two Datron calibrators I intend to fix up some day (4708 fully optioned and a 4700 that might become a parts machine for it), beautiful machines! Glad to hear the team is still working in Fluke.

You're right, the capacitors are AC rated which I completely missed. I'll highlight your comment to point this out. I'm still not sure why the simulator I used suggested doubling the voltage OR why the capacitors failed over time, both suggest overvoltage was the root cause. AN954 says this capacitor "should" be rated at double mains but not why. Thoughts welcome!

@@bansci X2 capacitors is in fact failing over time, and that is common problem in capacitive voltage drop circuits. They fail because over-voltage spikes at mains line, two main reasons for spikes is lightning and moments when powerful inductive loads are connected or disconnected from mains line (like big motors in industrial equipment, huge compressors in air conditioning systems, etc.). And when X2 capacitors are failing, they do it in a very specific way, they are gradually loosing capacitance and become open circuit. They are made of two rolled up metalized dielectric strips, when over-voltage spike occurs, you get discharge spark between two metalization layers (electrodes) of the capacitor. As result, metalization around spark area become vaporized, in this way capacitor newer gets shorted, but every time such event happens, it loses some metalization and at the same time some capacitance. And of course, if you will use capacitors with higher voltage rating, they will last longer.

I cant find them anywhere as well

I'd love a 3458A, it's the classic! I had the choice of course but managed to get a great deal on the fluke in the end. I think you need a calibrator next, or maybe a resistance and current mode on a PDVS3 maybe?

The interface is definitely a missed opportunity, especially how good the Keithley's are. Still, the specs on the fluke are out of this world...

Thanks for the thoughts, all great points!

Thanks for this content! Do you have any more information about this somewhere?

In the schematic (page 41 of the user & service manual pdf) you can see that the battery is used as a floating offset source. It doesn't have a V-ref. Input voltage is chopper amplified and then showed on the analog meter.

@@electrobert8874Thanks I went back and watched my video again till I saw the schematic and it makes perfect sense! A nice stable (over short times) low-impedance voltage reference you can reverse to determine the offset voltage. Thanks for the correction!

Sorry, I don't have one of those units or the firmware...

@@bansci Ok, no problem, tnks

I can't remember exactly how but it was a very painful process, I think the plastic clips over something meaning you have to flex it out, very nerve wracking when you have aged and brittle plastic!

I think low-distortion-nuttery is just as addictive as volt-nuttery, or time-nuttery, except it's easy more expensive as you start chasing the hertz, and gigahertz... Save yourself!

Lol ! but but but the sinewaves ? :)@@bansci

If you're talking about the PSU on the bench in the lower right, that's a donor PCB I got off eBay when I thought the issue might be with a switching transistor or some other part. I didn't think it would be a simple resistor failure but now I know better! If you mean the barrel jack in the back, that's a output for powering some other peripheral, I don't think it can be a power input.

So far so good, I haven't used as much as I thought. Other dmms like the DMM6500 and DMM7501 are just so much better for general experiments, but this does what it's supposed to do, which is be the last word in precision!

Hey, the units are well worth $200, but I only use it when I'm messing around with SMPS. I would recommend making your own charger to save money, you can shave down some barrel jacks to the right size, but it will take some iterations.

Your valve might need servicing, also check your upstream pressure, perhaps you have other things switching on the line affecting the pressure?

Sir ​​⁠@@banscithanks for support. I serviced the valve no any seal found in damaged condition then all cleaning done and fitted again also checked the line pressure found ok & other valves are working on same pressure. Now I found only fixed value 240.43 during startup. Can suggest how to resolve this issue. when I operate the valve by hmi no any gas flow increase shown on display. sir can I connect with you if possible on mail id or WhatsApp number.

@@rajeshsain3591 Hi, I'm sorry I'm not an expert in repairing these, and I can't offer support. It may be with the oscillation that you have bad PID settings, but if the flow rate is stuck now that's a new problem. Good luck!

Ouch!

So the MFCs I've shown at the start of the video can be controlled using a python library (github.com/numat/mfc). I've also designed a analog control board, and the code is here for the arduino controller (gist.github.com/toastedcrumpets/3ee78ff61feda329bbbc7c1797fa876f), but I don't think that's what you want.

@@bansci yeah I'm using arduino (trying to, anyways, lol. I suck at C/C++)

@@jhyland87 Ah OK, one day I hope to release a board for controlling analog MFCs via a web/wifi/BLE interface but I'm a long way off wrapping that project up! I got this far with it oshwlab.com/m.bannerman/banflow (its not WIFI but it does work!)

@@bansci Very impressive, even without WIFI. I'm making a nitrogen generator, I know I don't actually need Arduino for that, but it's a great excuse for me to buy a bunch of neat stuff and finally learn how to code C/C++. Im a software engineer, but mostly web type stuff (lately it's been all NodeJS), so lower level languages like C++ are a bit foreign to me.

Ah cool project! I want one too, but I've not made it. Was planning to follow applied science th-cam.com/video/7PWESWqhD8s/w-d-xo.html. What's your design?

Hi, so the MS is in a vacuum which is "leaky". The sample gas "leaks" into it continuously, and a vacuum system constantly removes this sample gas to maintain the vacuum. To introduce a sample gas, you just place it near the leak. All of the sample gas doesn't all need to go into the MS, so you flow the sample gas past the leak. The leak being a tiny hole stops too much gas entering (removing the vacuum). So with a GCMS, you have a high pressure at the start of the column, that drops down to more-or-less room pressure by the time it exits the column to the detector. If the detector is a MS, then it flows past a sample port for the MS before being released into the lab or into an extraction system. Hopefully this helps understand the pressures!

Yeah, the device is great, very well made, but I didn't realise the issues around its software and this has sort of spoiled it for me. They're still releasing their own software and selling the devices though.

Hey, can't remember exactly now. Something like one of these uk.rs-online.com/web/p/rtd-sensors/2364261 Definitely 4 wire PT100 and class B or better. Was the best I could buy on RS. No calibration certificate though and I did not anneal the thing or do anything special. Good enough for this job though!

I don't think there's any special trick, just only research equipment you want and you have a chance of buying. The chance bit is probably what you need to get right. I don't check eBay often as prices are high in the UK. But I keep an eye on the test equipment Google groups and check out their adverts, as usually prices are more reasonable so it's worth the effort. Same is also true for clearance auctions that sell company equipment, you can occasionally get amazing bargains but you must be careful not to get carried away

From the manual "The MKS IP Address format is 192.168.2.X, so the Host IP Address must be of the same format. A recommended Host IP address is 192.168.1.Y with a Subnet Mask of 255.255.252.0, where Y is some number between 5 and 254" This means you will need to scan the subnet 192.168.2.X for any http servers. You can do this using tools like NMap, or just try pinging all X=1 to X=254 values using a script. You could also try a broadcast ping, by pinging 192.168.2.255, this should cause all devices in the subnet to respond. Only the port scan is guaranteed to work though, some devices ignore pings.

diyaudiostore.com/collections/frontpage/products/matched-jfets?variant=39335247020105 Now you have no excuse :-P

@@bansci Thanks I am registered on the DIYAUDIO website many years I posted a lot of posts there about a DAC I built At the time they sold in the store they did not make deliveries to Israel I see they fixed it I checked now including shipping $47 I will later order a set from them I am currently more focused on the project of improvements to my spectrum analyzer R&S Looking for a good source for a 10 MHz rubidium reference I regret that I did not purchase it in the time that was on stock from a supplier tech mart in Israel for less than 50 dollars not working it very easy to fix them

@@davidaz4933 Ah you're in Israel? I always see excellent test equipment for sale from there on eBay, but the taxes and shipping are too much to the UK. Regarding frequency references, I really like BG7TBL's GPSDO, it has a second hand quality ovenized crystal in it, mine was a Trimble. He also does a frequency analyser too which seems well respected (called the FA2). The GPSDO needs to be left on, but I found it as good as my rubidium as far as I could test.