hybridfree/eevblog-posts huggingface dataset:
Quark multimeter - Page 1
Forum section: electronics / general

author: MegaVolt
author_rank: Frequent Contributor
timestamp: August 13, 2021, 11:59:29 am
content: I got this project: it looks very interesting.https://www.crowdsupply.com/mulin/quark

author: fcb
author_rank: Super Contributor
timestamp: August 13, 2021, 02:54:35 pm
content: That sharp end will either break off, or stab you when you are least expecting it, etc... They need to make it retractable or removable/replaceable.Also, the grounding - this happens through the USB port? 3.3A?

author: guenthert
author_rank: Frequent Contributor
timestamp: August 13, 2021, 04:34:51 pm
content: Shouldn't that go into the Test Gear section?

author: TimFox
author_rank: Super Contributor
timestamp: August 13, 2021, 04:42:31 pm
content: That looks like how the junior engineers (before I retired) used scope probes: first, lose the “witch’s hat”, then put the ground wire aside, then lose the ground wire, then return the useless probe to whence it was borrowed.

author: xrunner
author_rank: Super Contributor
timestamp: August 13, 2021, 05:16:18 pm
content: It shows the SMD number code and color code of components based on their resistance or capacitance from some internal library - that's interesting ...

author: Kleinstein
author_rank: Super Contributor
timestamp: August 13, 2021, 05:27:11 pm
content: The input does not look very fast, so the long ground lead may not be such a problem.The display at the end of the probe can still be a bit unconvenient - you just don't see the tip anymore. With a wireless display it may be OK - though more like a tiny, limited frequency scope and not a DMM replacement.The still have to invent the wireless ground lead.

author: The Soulman
author_rank: Super Contributor
timestamp: August 13, 2021, 06:19:35 pm
content: Quote from: Kleinstein on August 13, 2021, 05:27:11 pmGround is likely (high impedance) ac coupled thru the operators hand.

author: Kean
author_rank: Unknown
timestamp: August 13, 2021, 08:14:30 pm
content: Quote from: guenthert on August 13, 2021, 04:34:51 pmOr even better, the Crowd Funded Projects section.

author: bdunham7
author_rank: Super Contributor
timestamp: August 13, 2021, 08:18:28 pm
content: Measures voltage from 0 to 26 VMeasures current from 0 to 3.2 AMeasures resistance from 0 to 2 MΩMeasures capacitance from 2 pf to 1000 uFMeasures inductance up to 1 HOscilloscope has a sampling rate of 400 kHz

author: The Soulman
author_rank: Super Contributor
timestamp: August 13, 2021, 08:42:09 pm
content: Quote from: The Soulman on August 13, 2021, 06:19:35 pmNot if it does more than only producing wobbly lines on a tiny screen.I do wonder what that factory makes during the Saturday afternoon shift, or this is it.

author: tszaboo
author_rank: Super Contributor
timestamp: August 13, 2021, 10:02:40 pm
content: This is one of those objects that are useless without extra things that completely break the design.
US ADR1000 small group buys... - Page 1
Forum section: electronics / general

author: martinr33
author_rank: Frequent Contributor
timestamp: September 18, 2021, 05:54:18 pm
content: I would like one, or maybe two, of these but am discouraged by the MOQ of 5.I'd guess with shipping and tax they would end up around $75 each (a bit less for more than one in a box).So who wants/needs one. I am not looking to get a group buy of many more than 5 or so at a time, but we can get a few small spenders together.We could probably also so with a burn-in PCB design. Or maybe we just use 3458A boards, a likely target once the software mods are completed.

author: ramon
author_rank: Regular Contributor
timestamp: September 18, 2021, 11:59:39 pm
content: I was thinking exactly the same (a few units), but I am in Taiwan. Good idea about sharing PCBs, Cellularmitosis did a nice 3458a clone years ago.Edit:Burn-In PCBs:https://github.com/pepaslabs/dr-frank-ltz1000https://github.com/pepaslabs/hp-03458-66509-clonehttps://github.com/pepaslabs/px-refHow about adding a TO-5 Socket too? Was it TE 8058-1G32 the LTZ1000 socket?

author: laswellsh
author_rank: Newbie
timestamp: September 19, 2021, 09:06:49 pm
content: I would be interested in buying two.
Low Thermal Mass Banana Plugs - Page 1
Forum section: electronics / general

author: enut11
author_rank: Super Contributor
timestamp: August 02, 2021, 06:46:21 am
content: Does anyone know where to buy these low thermal mass banana plugs?They consist of a thin walled open tube. Labels are "MC" and "1.0"

author: Vgkid
author_rank: Super Contributor
timestamp: August 02, 2021, 07:35:16 am
content: Those are staubil sls4-b connectors , unfortunately I cannot help you with buying them. they don't seem to have any didtributors in the us either.

author: MiDi
author_rank: Frequent Contributor
timestamp: August 02, 2021, 07:50:45 am
content: They are Stäubli / Multi Contact SLS4-B (LS4 + KT4-B).E.g. awailable fromBuerklin

author: doktor pyta
author_rank: Frequent Contributor
timestamp: August 02, 2021, 02:50:33 pm
content: Elfa Distrelec: 140-48-007+ 140-48-058+ 140-48-061

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: August 02, 2021, 06:48:53 pm
content: Have a look in their international business online shop:https://www.distrelec.biz/en/laboratory-o4mm-19a-30v-gold-plated-staeubli-electrical-connectors-22-1005/p/14048007?track=true&no-cache=true&marketingPopup=false140-48-007140-48-058140-48-061SLS4-B SLS4-B/N SLS4-B/E SLS4-B/E/NElement14https://au.element14.com/search?st=sls4-bBest regardsScoobyDoo

author: enut11
author_rank: Super Contributor
timestamp: August 02, 2021, 08:16:31 pm
content: Hi @ScoobyDooThat link does not work for me.enut11

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: August 02, 2021, 08:22:22 pm
content: Quote from: enut11 on August 02, 2021, 08:16:31 pmWorks for me. Not a ScoobyDoo problem I guess. Using chrome, google.Try googling using something like "distrelec staubli gold-plated connector"I get ScoobyDoo's link and lots of other possibilities.

author: Andreas
author_rank: Super Contributor
timestamp: August 02, 2021, 08:58:44 pm
content: Hellosee also RS-components 103-8472https://de.rs-online.com/web/p/messleitungen/1038472/with best regardsAndreas

author: lowimpedance
author_rank: Super Contributor
timestamp: August 02, 2021, 11:57:59 pm
content: If non stackable is OK Element14 have their home brand Multicomponent part number ; 2802137 , in red and black.The Stäubli do look much nicer and available in various colours from Element14 too.
Datron Wavetek 4920 AVMS manuals - Page 1
Forum section: electronics / general

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: August 03, 2021, 04:53:32 pm
content: I am on the hunt for the following manuals. Any leads would be greatly appreciated.Wavetek 4920 AVMS manualsPart numbers:Users: 850264Maintenance: 850265Reference: 850266Quick reference: 850912Wavetek 4922 manual or documentation
HP 3458A 114 System Error - Page 1
Forum section: electronics / general

author: enut11
author_rank: Super Contributor
timestamp: August 02, 2021, 07:28:21 am
content: To the HP3458A gurus, is a "SYSTEM ERROR 114" a serious  problem?Not mine, just looking at an eBay listing...

author: Villain
author_rank: Regular Contributor
timestamp: August 02, 2021, 04:20:18 pm
content: Without any information it is almost impossible to tell what exactly is broken.I am still going to take a guess, faulty A3 board.When you buy/repair the unit let me know what it was

author: TiN
author_rank: Super Contributor
timestamp: August 02, 2021, 11:01:07 pm
content: Yep, what is the full error. Repair could vary from $80 up to $3.2k depends on unit condition and full fault reason.
Acoustic Reflectometer calibration - Page 1
Forum section: electronics / general

author: Roberts_Curiosity
author_rank: Contributor
timestamp: July 30, 2021, 01:15:46 pm
content: Anyone here know how to calibrate a medical Acoustic Reflectometer?What I really want to do is buy the calibration equipment.As best I can figure, such a calibrator would need an artificial ear that can simulateboth a healthy and diseased tympanium (as in an "ear drum").Thanks, Bob
Tympanometer Calibration - Page 1
Forum section: electronics / general

author: Roberts_Curiosity
author_rank: Contributor
timestamp: July 30, 2021, 06:30:46 am
content: Anyone here know how to calibrate a tympanometer?What I really want to do is buy the calibration equipment.As best I can figure, such a calibrator would need an artificial ear that can simulateboth a healthy and diseased tympanium (as in an "ear drum").Thanks, Bob

author: daisizhou
author_rank: Super Contributor
timestamp: July 30, 2021, 11:30:37 am
content: Are you calibrating medical equipment?

author: jpanhalt
author_rank: Super Contributor
timestamp: July 30, 2021, 12:09:13 pm
content: Standards are available and may vary by instrument. Here are CDC recommendations:https://www.cdc.gov/nchs/data/nhanes/nhanes_09_10/audiometry_09.pdfApparently the validation (page 2-36) applies to a specific brand. My suggestion is to search on your brand.

author: Roberts_Curiosity
author_rank: Contributor
timestamp: July 30, 2021, 12:35:02 pm
content: Yes.

author: Roberts_Curiosity
author_rank: Contributor
timestamp: July 30, 2021, 12:37:11 pm
content: To: jpanhaltThank you. That document is very helpful.

author: daisizhou
author_rank: Super Contributor
timestamp: July 30, 2021, 01:08:23 pm
content: Host, send a physical map to see。I am calibrating the gasflow analyzer(Test ventilator)
IFR FM/AM 1100S Radio Test Set AN/GRM114A scope inverter repair - Page 1
Forum section: electronics / general

author: Paul29E
author_rank: Newbie
timestamp: August 18, 2020, 01:14:39 am
content: Hello, I need help fixing my test set, any calibration specialists still around? I am trouble shooting a scope inverter module on a IFR FM/AM 1100S radio test set. I was monitoring over the air signals on the combination oscilloscope and spectrum analyzer when a burning smell started and the scope waveform distorted. After unplugging the test set, I removed the cover and discovered a blown tantalum capacitor C11 150uf 15V that filters the 12vdc and a burned resistor R2 68ohm 1/4 watt that is on the emitter of Q1 transistor MPS-A13 which is a start up circuit. After replacing both parts it happened again after turning on the scope, I immediately turned off the scope and unplugged the set. After removing the blown capacitor I monitored the 12vdc feed for the inverter module (4000 scope inverter), 12vdc feed tested ok. I took Q1,C10 and C2 out of circuit and they tested ok. What do you think I should look for next?Thanks, Paul

author: Grandchuck
author_rank: Super Contributor
timestamp: August 18, 2020, 01:53:00 pm
content: C1 and CR1.

author: Paul29E
author_rank: Newbie
timestamp: August 19, 2020, 12:07:04 am
content: I will check C1 and Cr1 when I take it back apart. I did a visual check and they weren't burned up. C11 blew up twice and R2 burned with it. I need to check Q2 and Q3 also. Maybe it’s a common failure. Thanks for the help.

author: Paul29E
author_rank: Newbie
timestamp: August 04, 2021, 01:45:09 pm
content: Replaced blown C11 150uf 15V that filters the 12vdc and also a burned resistor R2 68ohm 1/4 watt. Found C2 capacitor reversed and R1 was the wrong value. I replaced tantalum C10 and C11 with 25vdc 150uf electrolytic caps and repaired burned circuit board. Q1, Q2, Q3, CR1, C1, C2, R1, R2, R3 and R19 all replaced with correct values on schematic. Oscilloscope and Spectrum Analyzer work good now. Thanks for the help.
affordable calibration in Italy?  - Page 1
Forum section: electronics / general

author: pizzigri
author_rank: Regular Contributor
timestamp: July 13, 2021, 07:58:53 am
content: Hi everyone,I tried searching this but it gave either old or very poor results. As a hobbyist, I tend to purchase older or used equipment, and obviously most of it has no calibration or is so old that it lost completely any cal it may have had. Case in point- a PM2534 DMM with a depleted memory battery.Again, as a hobbyist i do not have access to a metrology lab and budget from family income is scarce, and prices i have seen for calibration are out of this world where I live - granted, they are geared to big companies that have the money, but still, 250-300 Euro plus taxes for 6.5 digit DMM cal is way more I paid for that DMM. And, I have no way to recover VAT (22%).As a hobbyist, I don't need any certificate or document, or even a list of recorded values, I just need the confidence that what I see on the LCD of my meter is reasonably what the actual DUT value is.Last but not least, I have found n Ebay sometimes people that advertise cheap calibration .- something like 60 euro or so.Seems great!Called them up, and I was appalled to candidly being told that only ONE or TWO ranges are actually calibrated, and only for the V and R - no current or AC calibration!So my question - is there in Italy someone that can calibrate for a resonable fee our instruments? That has a 5700 series calibrator and a good resistor standard box? Without certificate.The alternative would be to have a transfer standard, I have a 34410A that is calibrated, but how to transfer the values to the other DMM? Especially the AC or I, which are not trivial.Franco, in Rome Italy

author: fant
author_rank: Contributor
timestamp: July 16, 2021, 10:49:07 pm
content: I have these two references:http://www.spinelectronics.eu/site/index.php?module=ecatSite&method=serviziCalibration and adjustmenthttps://www.rf-microwave.com/it/home/(rota Franco) It is not properly a calibration lab, but if you ask him kindly he is very friendly.Mandi
74VHC4052AFT mux type - make before break / break before make  - Page 1
Forum section: electronics / general

author: Ribster
author_rank: Frequent Contributor
timestamp: July 09, 2021, 01:33:00 pm
content: Hi allI'm designing a resistance measurement thing.It will have a constant current sink inside. This will be achieved with the MAX8515.To select my ranges i would love to incorporate a 4:1 mux.I've selected the 4052. But for the life of me, i cannot find the type of the mux.So the switching behaviour. Brake before make or make before break.From page 12 of the toshiba datasheet, AC Test Circuit i would assume a break before make behaviour, but i don't have 100% assurance about this.Anyone has some experience with the 4052 ?Kind regards

author: Kleinstein
author_rank: Super Contributor
timestamp: July 09, 2021, 02:41:02 pm
content: I have not look much at 4052, but on the same serie 4053: there is a relatively short break before make time - not much (e.g. 10-50 ns), but usually enough to ensure there is no cross conduction. The different series (HC, AHC, VHC, LV) can be a bit different. Resistance measurement should not really case much about 10 ns range timing. For the 10 ns time scale there is also the charge injection that becomes relevant - so there is additional current from the gates, not just between the inputs.

author: edavid
author_rank: Super Contributor
timestamp: July 09, 2021, 04:50:43 pm
content: As you have noticed, this behavior is not defined in the datasheet. If you need break before make, you should add blanking time. If you need make before break, use a different part.What is it about your circuit that requires you to know this?

author: Ribster
author_rank: Frequent Contributor
timestamp: July 10, 2021, 08:32:22 am
content: Thanks all for your input.It is the right part price wise and spec wise.Im using it to select a resistor. My fear is that i switch and the MAX8515 does some crazy things.So i've placed a resistor in parallel over this switching. That way the circuit does not see an open for 10ns.I hope this one will be sufficient!
How to test for electrolytic polarity? - Page 1
Forum section: electronics / general

author: solarbot
author_rank: Regular Contributor
timestamp: July 08, 2021, 03:32:53 pm
content: Hi,I have a set of electrolytic caps which seem to have just the one polarity indicator and that is the leg length..... with the legs cut to the same length, is there a way to determine the polarity through testing? Cheers.

author: David Hess
author_rank: Super Contributor
timestamp: July 08, 2021, 04:09:13 pm
content: Quote from: solarbot on July 08, 2021, 03:32:53 pmLeakage will be much higher in the reverse direction at low voltages, so a low value current source can be used to charge the capacitor in both directions and safely reveal the correct polarity.

author: PA4TIM
author_rank: Super Contributor
timestamp: July 08, 2021, 04:23:26 pm
content: There are non polarized electrolytics.

author: solarbot
author_rank: Regular Contributor
timestamp: July 08, 2021, 04:55:18 pm
content: I didn't know that there were unpolarised electrolytic caps - this one has a long leg and a short leg so guessings its not one of them?..... although this one has NP on the casing and a diamond shape with dots at the corners so perhaps it is?If I chargre the cap (rated 16V) with a 9V battery and then measure the voltage with a multimeter, I should see the volatge drop more quicky when reverse charged?

author: bdunham7
author_rank: Super Contributor
timestamp: July 08, 2021, 05:40:44 pm
content: Quote from: solarbot on July 08, 2021, 04:55:18 pmA photo would help identify them, although if they don't have any polarity indication and they say "NP" on them, that's a pretty strong indication that they are non-polarized.

author: solarbot
author_rank: Regular Contributor
timestamp: July 08, 2021, 07:02:36 pm
content: Thanks folks, I think learning that there are non polarised electrolytics and measuring the leakage gives me confidence that this is a non polorised capacitors - the body is also bigger than an equivalent polorised cap so it all makes sense.Thank you, I have leanrt something newCheers.
KME-*** Low capacitance standard's - Page 1
Forum section: electronics / general

author: shodan@micron
author_rank: Contributor
timestamp: July 01, 2021, 02:54:26 pm
content: void

author: HighVoltage
author_rank: Super Contributor
timestamp: July 01, 2021, 02:58:37 pm
content: Nice!Does the datasheet / calibration report say anything about what frequency the standard is suppose to be tested at?

author: HighVoltage
author_rank: Super Contributor
timestamp: July 06, 2021, 12:08:08 pm
content: You have interesting stuff in RussiaWhat instrument did they use to certify 0.001001 pF in 1982?Kind of impressive!
AVK-6 ultra low noise coaxial cable - Page 1
Forum section: electronics / general

author: shodan@micron
author_rank: Contributor
timestamp: June 26, 2021, 07:31:57 pm
content: void

author: TimFox
author_rank: Super Contributor
timestamp: June 26, 2021, 08:11:59 pm
content: To understand the specification: what voltage is across the cable when the noise is measured during vibration (10 and 40 G acceleration)?I first thought the dielectric is coated with graphite, from the picture, but the spec reads "conductive fluorosiloxane" for the black layer.

author: bsw_m
author_rank: Frequent Contributor
timestamp: June 26, 2021, 08:19:34 pm
content: Quote from: TimFox on June 26, 2021, 08:11:59 pmNoise specs:<30uV at 10G acceleration and 40Hz test freqand<250uV at 40G acceleration.I also want to note that in cables of this series (AVK*), a conductive layer of graphite has never been used.Special compositions "ФС" are used - special conductive fluorosiloxane elastomers.

author: TimFox
author_rank: Super Contributor
timestamp: June 26, 2021, 08:59:48 pm
content: Yes, I understood the frequency and acceleration values, but was wondering if this was done at 0 V across the cable. With DC on the cable, the noise would go up during the vibration tests.

author: TimFox
author_rank: Super Contributor
timestamp: July 05, 2021, 05:20:03 pm
content: How do you remove the black conductive layer over the dielectric? Only by careful knife work?

author: Zoli
author_rank: Frequent Contributor
timestamp: July 06, 2021, 04:07:42 am
content: Quote from: shodan@micron on June 27, 2021, 04:03:33 amIf thePTFE is etchedbefore bonding, the bond can be pretty tough - don't ask me how I know.As sidenote, the etchant isn't really high-tech: naphtalene based...
Fluke 5700 capacitors power supply list - Page 1
Forum section: electronics / general

author: jfphp
author_rank: Regular Contributor
timestamp: July 08, 2021, 11:04:03 am
content: Hello,Did anybody make a list of the electrolytic capacitors (with their common part numbers available by Digikey or others ditributors) to be replaced especialy in the regulator board A17. Just to spare a lot of time... Thank you

author: veedub565
author_rank: Frequent Contributor
timestamp: July 09, 2021, 10:43:38 am
content: That would indeed be a nice list to have as this is something I need to do too. A lot of work to make such a list though.The service manual does in fact list components for each assy including description, Fluke stock no, Manufacturer stock number, manufacturers part number, and the qty of each required.It's just going to take some time to make up a shopping list from the usual suppliers.
Precision Voltage Reference APEX VRE 310 - Page 1
Forum section: electronics / general

author: IRFP
author_rank: Contributor
timestamp: May 24, 2021, 10:05:20 am
content: Hello,This morning I came across this voltage reference from APEX, the VRE 310 with the spec below:Output +10V, ±1.0mV (0.01%)- Temperature drift: 0.6 ppm/°C- Low noise: 6μVP-P (0.1-10 Hz)- Industry standard pinout: 8-pin DIP or surface mount boxSurface mount- Excellent line regulation: 6ppm/V typical- Output adjustment capabilityThe VRE310 is a high accuracy, low cost +10V reference. Available in an industry standard 8-pin DIP or SMT package.SMT, this device is ideal for upgrading systems that use lower performance references.The device provides an ultrastable +10V output with an initial accuracy of ±1.0mV (0.01%) and a temperature coefficient of 0.6ppm/day.temperature coefficient of 0.6ppm/°C.What is your opinion on this component? Do you think it can be integrated into a serious 10 V reference project?

author: Andreas
author_rank: Super Contributor
timestamp: May 24, 2021, 10:35:20 am
content: Hello,I have only experience with VRE3050AS (5V version) from Thaler/Apex.I bought 2 devices from DigiKey some years ago.T.C. performance was good near room temperature.But 1/f noise was well above comparable 5V devices. (9 uVpp instead of 3-4 uV of a AD586)(also power consumption was too low compared to the data sheet).And also the hysteresis was above 1 ppm.I cannot tell if I simply had bad luck and got "mondays devices" short before Apex bought Thaler or if it is really the performance of those devices.At least TI seems to be convinced of Thaler references in one of their application note.For the price I rather select several AD587JQ devices to pick one with a low T.C. near room temperature.https://www.eevblog.com/forum/metrology/ad587lw-10v-precision-travel-standard/msg1449487/#msg1449487with best regardsAndreas

author: d-smes
author_rank: Regular Contributor
timestamp: May 24, 2021, 11:21:43 am
content: I also found the VRE references to be quite noisy. I bought the 2.5 and 5V versions years ago. I see most models are discontinued at DigiKey.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: May 24, 2021, 01:30:35 pm
content: Some researches of VRE305 and VRE310:http://radiokot.ru/forum/viewtopic.php?p=3997380#p3997380(use Google Translate)

author: IRFP
author_rank: Contributor
timestamp: May 24, 2021, 06:53:36 pm
content: Good evening,Thank you for your feedback, the price is particularly high, the VRE310JS version at MOUSER is 89,83 € per unit!
Bradley electronics - Voltage Calibrator Type "134” - Page 1
Forum section: electronics / general

author: Erik L
author_rank: Contributor
timestamp: May 15, 2021, 06:43:10 pm
content: Dear fellowsPlease forgive me if I make any mistake and feel free to correct me as this is my first post on the EEVblog Electronics Community Forum.I have a request regarding an instrument that I have been collecting from what I like to call “a mine” of vintage instruments (several hundreds of them) here in Norway last year.Anyways, the brand is “Bradley electronics” and the model is “Voltage Calibrator Type 134”.I have been looking everywhere on the internet and could not find any traces of it.The calibrator is working ok considering its age; it’s quite accurate and stable measured against a calibrated meter. I have not opened the beast yet.From the back side of the instrument, I can see two TT22 and one EL360 tubes.Does anyone sit on information such as manual / technical specifications?Any contribution will be much appreciated.

author: mrk
author_rank: Newbie
timestamp: May 16, 2021, 09:15:12 am
content: https://www.vintage-radio.net/forum/showthread.php?t=160342"I have these and other Bradley/Pulsetek manuals (123, 125B, 125C,134, 156, 158, 171B, 187 counter timer, 192, 200, 232 AC calibrator). "https://www.vintage-radio.net/forum/showthread.php?t=131406"Test gear dilemma. Bradley type 134 precision voltage calibrator."https://www.vintage-radio.net/forum/showthread.php?t=131768" Bradley 134 Voltage Calibrator"Look Mum no Computer got one of those too youtube.com/watch?v=0Eo3Kn05SdU&t=683s

author: Erik L
author_rank: Contributor
timestamp: May 16, 2021, 09:27:42 am
content: Thanks mrk.I am on the trail but still no documentation.Working on it.Erik
Uni-T UT70D Multimeter Calibration - Page 1
Forum section: electronics / general

author: cemelec
author_rank: Contributor
timestamp: May 11, 2021, 02:16:55 pm
content: I've search high and low for info on how to calibrate a UT70D multimeter, including these forums, no luck. It has been posted here before, but that was a few years ago.Basically its an 80,000 count device, quite nice and capable of good precision and it was spot on when I first got it maybe 6 or 7 years ago (Maplin). Now the voltage readings are significantly out and I'm hoping to fix it rather than put it in my junk pile.I've totally disassembled it and there is not a single trimmer pot in sight, confirming the schematic (found in this forum)I emailed Uni-T but as expected no response. There is no mention of it on their website, not even as discontinued, so they have probably totally abandoned itMaybe its done via some key sequence? Anyone have the remotest idea?Thanks

author: cemelec
author_rank: Contributor
timestamp: May 15, 2021, 04:14:58 pm
content: OK, I've abandoned all hope of getting support from Uni-TInstead, and it works fine so far, is a bit of PCB trace cutting and substituting one of the resistors in the Vref path with a fixed resistor + trimmer pot. Now able to trim reading to match an external voltage reference, so I've rescued a fairly decent meter from the junk pile.

author: MosherIV
author_rank: Super Contributor
timestamp: May 15, 2021, 07:24:23 pm
content: Normally you find a local company that specialises in calibrating test equipment/multimeters and get them to check calibdation and adjust if needed. The cal is then referenced to national standardsa and are traceable.I have the B variant. There are 6 pots inside for adjusting the calibration. I have never found the calibration procedure online.However, most dmm calibration rarely drift. Mines has never drifted.Some people disslike Uni-T because some models are very poor and their calibration does go after a while.
C5-60T precision wire-wound resistor - Page 1
Forum section: electronics / general

author: shodan@micron
author_rank: Contributor
timestamp: June 15, 2021, 01:15:12 pm
content: void

author: doktor pyta
author_rank: Frequent Contributor
timestamp: June 15, 2021, 03:43:59 pm
content: Why semi-precision?I'd say that hermetic sealing give them long term stability and make them suitable for metrology-grade applications.P.S. I own 4 of these, all with T.C. of about 1ppm/C.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: June 15, 2021, 06:26:40 pm
content: No problem to buy a slightly better "thing"

author: TimFox
author_rank: Super Contributor
timestamp: June 15, 2021, 08:45:28 pm
content: The digital readout on the meter is a good example of why we must be careful with majuscule and minuscule prefixes:1 P= 1 kV / pA = 1 V / fA.

author: branadic
author_rank: Super Contributor
timestamp: June 16, 2021, 07:52:57 am
content: Looks like they used some insulator made out of PEEK. Could you take a detailed picture of how the leads are attached to the bobbin and how they attached the wire to the leads? Thanks.-branadic-

author: wan1788
author_rank: Newbie
timestamp: June 16, 2021, 08:22:33 am
content: Quote from: branadic on June 16, 2021, 07:52:57 amIn the third photo of the second post, there are folding petals. They are clearly visible on the side cage. The resistor leads are made of magnetic material and have a high thermo efm.

author: ramon
author_rank: Regular Contributor
timestamp: June 16, 2021, 11:44:32 am
content: I have count 160 turns. What is the diameter of the ceramic core? And the length between the first turn and the last one?

author: ramon
author_rank: Regular Contributor
timestamp: June 16, 2021, 02:41:28 pm
content: Thank you so much !!!This reminds me some experiment I made some time ago. Will need to find time to continue ...

author: ramon
author_rank: Regular Contributor
timestamp: June 16, 2021, 02:56:13 pm
content: If the number of turns is correct, then I think that it should be 0.025mm wire.2*Pi*((7.487-0.025-0.025)/2) * 160 turns = 3.738 meters3.738 m * 2689 ohms/m = 10,052 ohms !

author: ramon
author_rank: Regular Contributor
timestamp: June 16, 2021, 03:32:57 pm
content: Interesting

author: Andreas
author_rank: Super Contributor
timestamp: June 20, 2021, 08:49:23 am
content: Hello,not bad result.for me additionally interesting would be if there is any hysteresis (or permanent shift) when cycling back to cold values.with best regardsAndreas
Siglent SVA1015X calibration problems! - Page 1
Forum section: electronics / general

author: Johndefreitas001@gmail.co
author_rank: Newbie
timestamp: May 07, 2021, 08:56:33 am
content: Hi,I've just purchased a Siglent SVA1015X last week and I'm trying to set things up, but it doesn't work the way it is supposed to.I have 2 N calibration kits with coefficients: one is Male the other Female.I also have 2 SMA calibration kits with coefficients: one is Male the other Female.My SVA came with the latest firmware version, which is: SW1 3.2.2.4.0, SW2 20201111-0, SW3 000000CA, HW 03.01.00There are two entries for user defined calibration kits within the Cal Kit sub menu, User1 and User2. I've entered my calibration kits coefficients in both of these entries, but when I run a calibration and apply this to the system, it doesn't seem to work. If I do a Smith chart check and leave my cable open, there is a shift in the Smith chart at the open position. It looks like the SVA doesn't apply the calkit settings or if it does it, it does it wrong. Also when I turn my SVA off, it doesn't save my user entries in the calkit settings. Can you please help me? The analyzer is useless to me if I'm not able to calibrate.
Dekatran standard transformer decade DT72A - Page 1
Forum section: electronics / general

author: NiaDebesis
author_rank: Frequent Contributor
timestamp: April 23, 2021, 04:18:03 pm
content: Hi there!One of my friends gave me one of this decade transformer, someone has a manuale regarding specifications? Because I never used one of this and I'd like to test It at the lab in the correct manner.

author: bsdphk
author_rank: Regular Contributor
timestamp: April 23, 2021, 06:12:00 pm
content: Look here:http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=06_Misc_Test_Equipment/ESI
Suggestions for a cal lab to ship to in the USA - Page 1
Forum section: electronics / general

author: Gridstop
author_rank: Contributor
timestamp: April 08, 2021, 06:15:32 pm
content: I'm fixing up a Keithley 2000 (just needs caps, everything else seems fine so far, might update firmware too). But it's at least 5 years since cal and doesn't have a sticker from any particular lab, so I want to get an initial full cal on it. Eventually I might join in on the US cal club here to keep an eye on it.There's no labs in town or within 4 hours drive of me (Midwest), other than the one at work which I can't use. The closest big city that would have labs would be Minneapolis, MN. But unless I could get one there to do it as next-day drop off & pickup while I'm on a vacation or something, I think I'll be stuck shipping. So I'm interested if anyone has had particular good/bad experiences shipping a DMM for cal to any particular labs in the US. The one that jumped out was the custom cal guys, offering standard cal for $95, plus of course shipping both ways, but it's hard to search for reviews for something like that. So I'm interested in any specific recommendations. Thanks!

author: ElizatronicWarfare
author_rank: Contributor
timestamp: April 13, 2021, 10:41:29 am
content: Well, that depends on what you want out of your calibration. Different labs have different capabilities.

author: Gridstop
author_rank: Contributor
timestamp: April 13, 2021, 12:51:43 pm
content: I have no specific needs in terms of certification or uncertainties. Just what most refer to as a 'standard calibration' for a 6.5 digit DMM, maybe possibly with before/after data if it's not too expensive.At this point I'd appreciate any reviews/testimonials/suggestions/warnings about any cal lab that does shipping. Even if someone here has shipped a DMM for cal and it just went 'fine' I'd take it at this point

author: ElizatronicWarfare
author_rank: Contributor
timestamp: April 14, 2021, 09:48:38 am
content: Well, the OEM would probably have the best capability to test the 2000 against its' specs. You could drop what's left of Keithley an email and ask about their rates.
Need some parts from dead SYMMETRICOM TS2500 or TS2700  - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: April 08, 2021, 10:36:32 pm
content: Well they say you should never throw stuff away!!!I had a pile of cards from defunct TS2700 units and after saving them for a couple years, (I did pull some parts from them for experiments!) I trashed them.Now I'm looking for a couple of the Vectron 60Mhz oscillators mounted on the main chassis to play with and don't have the cards any more?Anyone have one or more junk main boards? I really just need the oscillators so you could cut that section out of the board out or if careful unsolder the oscillators.Will pay $5.00 each + shipping for them.Cheers,Corby
source for ptf56 3.3k (E6) low volume?  - Page 1
Forum section: electronics / general

author: julian1
author_rank: Frequent Contributor
timestamp: April 04, 2021, 07:49:08 pm
content: Looking to get qty 5 - 10x. mouser are sold out until december. farnell have 3k as closest value.It's a common resistance value, which I assumed would be available. To use in a divider, so would prefer to stay within the ptf56 product range.

author: MiDi
author_rank: Frequent Contributor
timestamp: April 08, 2021, 09:07:49 am
content: Not sure why this is metrology relatedYour best friend isfindchipsandoctopart.At the moment onlyQuest Componentshave them in stock.Seems not only semiconductors are short on supply, had/have a couple of orderings for non semiconductor parts with lead time of up to half a year...

author: julian1
author_rank: Frequent Contributor
timestamp: April 08, 2021, 07:25:12 pm
content: Thanks, I ordered from Quest.It's odd that a resistance value like 3.3k/e6 is hard to get. The only use I know for these low-tempco prec through-hole resistors is metrology type applications - voltage references, and support circuity for adc/dac/sensors. Consumer electronics/ (affected by chipaggeden) is all surface mount as far as I know.I am left to wonder if smt could be a better alternative. panasonic era-series thin-film have a similar tempco (10ppm) to ptf56 and are much easier to get. If one really needed a foil resistor, then those are also available in smt.My assumption is that leaded parts are probably better isolated from mechanical stresses due to board temp changes. But I have also not seen any data to support that view.
IFR Aeroflex GPS-101 or GPS-101-2 service manual - Page 1
Forum section: electronics / general

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: September 22, 2016, 03:41:40 pm
content: Hello, would anyone have a service manual for one of these critters? Aeroflex claims that a since it is obsolete it is not available.........

author: tc0fh
author_rank: Newbie
timestamp: March 23, 2021, 09:03:36 am
content: Hello!Did you manage to find the service manual? I am in the same boat.ThanksAndrei
Running LH on my New PinePhone - Page 1
Forum section: electronics / general

author: bingo600
author_rank: Super Contributor
timestamp: June 23, 2020, 07:55:35 pm
content: Got my PinePhone (Linux) last week.CE UBports Edition (Ubuntu touch) , but i switched to Debian.I'm running "Mobian" on it , Debian + poshI hope texas-pyro will make an option to reverse the screen (Landscape) , once he's allowed back on Campus.That would be super for the : 5.95″ LCD 1440×720, 18:9 aspect ratioRight now there's some clipping , and landscape would be so much better on the phonehttps://www.pine64.org/pinephone/Storehttps://store.pine64.org/product/pinephone-community-edition-ubports-limited-edition-linux-smartphone/Afaik they plan a new batch around Aug/SepI'm connecting via TCP to a MOXA Serial-->Ether converter , where the tbolt is attached/Bingo

author: texaspyro
author_rank: Super Contributor
timestamp: June 24, 2020, 03:39:04 am
content: Quote from: bingo600 on June 23, 2020, 07:55:35 pmThe quarantined version of Heather can rotate the screen image. This was added when I added support for those tiny RasPi touchscreens.

author: bingo600
author_rank: Super Contributor
timestamp: June 24, 2020, 05:46:37 am
content: Quote from: texaspyro on June 24, 2020, 03:39:04 amThanx texaspyroAnd poor Heather , she's in quarantine.Hope she's getting better soon/Bingo

author: notfaded1
author_rank: Frequent Contributor
timestamp: June 30, 2020, 03:45:57 pm
content: I'm curious how well the phone works? Pretty neat a linux phone you can buy.

author: bingo600
author_rank: Super Contributor
timestamp: June 30, 2020, 05:20:39 pm
content: https://forum.pine64.org/forumdisplay.php?fid=121I like Mobian (Debian + posh) , but the UbuntuTouch , and PortMarket OS are also contenders.It is NOT your daily driver yet , but getting there.GSM calls works , SMS works , Batt time 10..12 hours (will get better)GPS should work tooCamera doesn't work yetIt improves week by week , and the selection of "working" OS'es (distros) is good.It's not a "Powerhouse" , but it will be a usable smartphone ,withoutApple or Google logging every keypress/sms/url or position , they can suck out of your phone./Bingo

author: cdev
author_rank: Super Contributor
timestamp: March 22, 2021, 10:56:39 pm
content: Does the multi GNSS system GPS chip support raw data/RTKlib, etc? Has anybody run RTKlib on it?
Wondering about heater circuit for LM399 - Page 1
Forum section: electronics / general

author: tkamiya
author_rank: Super Contributor
timestamp: March 18, 2021, 08:10:56 pm
content: I have been looking into making a voltage reference using LM399. According to its datasheet (uploaded) heater is to be connected directly to a power supply. I am familiar with how OCXO works, but how does LM399 regulate its temperature? There doesn't seem to be any feed back mechanism in equivalent circuit.

author: bdunham7
author_rank: Super Contributor
timestamp: March 18, 2021, 08:16:26 pm
content: Scroll down to page 6.

author: tkamiya
author_rank: Super Contributor
timestamp: March 18, 2021, 08:27:13 pm
content: Duh.... missed it entirely. Thanks!
Racal-Dana Series 9500 5 MHz OCXO, what to expect? - Page 1
Forum section: electronics / general

author: Hole
author_rank: Contributor
timestamp: July 15, 2020, 01:36:01 pm
content: Hi.Some years ago I got a Racal-Dana Series 9500 Universal Timer/Counter Unit as a bargin. It has a 5 MHz OCXO doubled to 10 MHz via SN74LS86N.I use it two or three times a year to check some basic values (has this cpu a clock signal?), so not really a device I want to spend much money in. But, as it is in life, recently I wanted to do some more precise measurements (look at the RTC of a ESP32).Question to all you metro gods and goddesses:-- What accuracy can be expected? (I know, guesswork. Just chat your experience...)-- How to (if needed) bring it to a reference "the cheap way"?ICs have a date code from about 1984/1983. I can provide photos.Thanks!

author: eevcandies
author_rank: Regular Contributor
timestamp: March 15, 2021, 10:59:22 pm
content: The racal high-stability time bases are extremely good, if you can find them...there are some postings on how to mod in one on your own as well.
Agilent DSO-X 2014A (New behavior) forgets the previous setup on power up. - Page 1
Forum section: electronics / general

author: LA7SJA
author_rank: Regular Contributor
timestamp: March 13, 2021, 02:28:39 pm
content: New Behavior. Every time I start up the scope, it is in default setup and not as it was the last time I turned it off. Previously, it remembered all the settings and started up the way I left it. Does this behavior have anything to do with the secure erase function? I think this started after "upgrading" to 02.60.2020101120. It also starts up with the hated select language shit, that should go away after the first ever start-up and not show up agin on power on and after screen saver exit. I REALY HATE THIS MISBEHAVIOR!LA7SJA

author: bob91343
author_rank: Super Contributor
timestamp: March 13, 2021, 11:33:37 pm
content: That is a common symptom for when the internal battery needs replacement.
PicoScope 2204A DC error - Page 1
Forum section: electronics / general

author: richlooker
author_rank: Regular Contributor
timestamp: March 04, 2021, 06:29:10 pm
content: My brand new PicoScope 2204A has a DC offset/error of ~+3mV on both channels, with probes shorted. According to the specs, the DC accuracy is ±3% of full scale ±200 μV - at +/-50mV scale, this translates to +/-1.7mV. My old non-A PicoScope 2204, whose death is the reason I bought a new one, always displayed zero signal at zero input. Is this a valid reason for returning it?

author: jpb
author_rank: Super Contributor
timestamp: March 04, 2021, 09:08:52 pm
content: I would certainly contact Picoscope.On most of their scopes this would be absorbed in the general offset but I don't think the 2204 has an offset option but it may be some easy setting in software.

author: richlooker
author_rank: Regular Contributor
timestamp: March 04, 2021, 09:57:01 pm
content: Quote from: jpb on March 04, 2021, 09:08:52 pmThere is an "offset" adjustment in software, but it offsets the entire scale, so the DC error reading stays the same.
Keysight is great :-) (be careful with super caps!) - Page 1
Forum section: electronics / general

author: niner_007
author_rank: Frequent Contributor
timestamp: March 04, 2021, 01:01:23 am
content: I had a super cap explosion in my lab. It sprayed a bunch of cap electrolyte over my test gear, some of the victims were few 34470As (hey but not the 3458A! who were farther apart) :/ Everything is functional, but the electrolyte is corrosive and it damaged the display glass and enclosure. I looked at the Keysight parts store, and wow, I thought only older test gear are supported, but actually I was able to order replacements for the front panel, and display glass, and replace them, and now they look brand new. This is so cool, I wish other manufacturers did this, and had the parts available. Keysight doesn't have it for all of their gear sadly :/ Anyway, funny thing is that the DMM7510 had no issue with the electrolyte because the plastic front panel has another sheet of plastic on top with the markings, and I guess that kind of plastic is resilient to corrosion. So anyway, DMM7510, corrosion tested! Keysight, awesome!Yes, I'm slowly emerging on the other side of grief

author: Stray Electron
author_rank: Super Contributor
timestamp: March 04, 2021, 01:09:02 am
content: That must have been exciting! What size capacitor and how what voltage was it charged to? I've never seen a super cap explode but I would expect it to be very"energetic".

author: HighVoltage
author_rank: Super Contributor
timestamp: March 04, 2021, 01:21:43 am
content: Was it a 2.70 V supercap?Pictures of the explode cap please!So far I was lucky with these caps.

author: Stray Electron
author_rank: Super Contributor
timestamp: March 04, 2021, 01:48:45 am
content: Quote from: HighVoltage on March 04, 2021, 01:21:43 amYes! Do it again so that you can video it!

author: niner_007
author_rank: Frequent Contributor
timestamp: March 04, 2021, 02:05:39 am
content: These are expensive caps!And massive, Maxwell BCAP0350, 350F, 2.7V, in a 3S3P configuration, my mistake was to assume it was a 6S configuration and leaving it connected after being fully charged to a 12V 40A supply (from a Xantrex 20V/60A DC supply, current limited to 40A). The explosion is really not that fun and terrifying, do not recommend

author: HighVoltage
author_rank: Super Contributor
timestamp: March 04, 2021, 04:04:33 pm
content: I have used lots of Maxwell 350F, 2.7V and have been very lucky so far and always wondered what will happen at overvoltage.So, you essentially overcharged about 1.3V / cap.How long did it take from the time of applying the voltage to the explosion.I assume you charged them with the PSU in current limiting mode.So they started at low voltage and slowly increased.Would be very interesting to see at what voltage and time they exploded.What I found most amazing on these 350F caps is the time they need to charge at 100A current.

author: niner_007
author_rank: Frequent Contributor
timestamp: March 04, 2021, 09:21:25 pm
content: About 2 minutes in, after they were fully charged
Keysight 34461A dual measurement Voltae and temperature - Page 1
Forum section: electronics / general

author: IconicPCB
author_rank: Super Contributor
timestamp: March 03, 2021, 06:38:32 am
content: 34461A has the option of ratio measurement.Other than the ratio approach is there any other way of simultaneously measuring voltage and temperature?What is the effect of ratio configuration on the measurement of voltage?

author: razvan784
author_rank: Regular Contributor
timestamp: March 03, 2021, 09:37:13 am
content: You can configure it to display the two individual voltages that form the ratio, as well as read them out via SCPI.As far as I remember you cannot do math on those inside the DMM, you need to do it in your own software.You can also configure the main input on whatever range you need, but the aux ("sense") input will autorange.Now you are limited in your options: either connect a thermocouple directly and somehow do the cold junction compensation (your accuracy will be quite poor) or use something that converts temperature to voltage, such as an industrial "temperature transmitter" which may give better accuracy but nowhere near what the DMM is capable of.Edit: Or maybe a LM35 or similar analog temperature sensor IC

author: IconicPCB
author_rank: Super Contributor
timestamp: March 04, 2021, 01:52:08 am
content: Thanks Razvan,I had not considered usinglm35 but that is not a bad idea. The readings would be direct.( on the secondary display).I had visions of setting up a voltage divider with a thermistor in one half and then massaging voltage reading into a temperature reading.
Some interesting stuff on sale - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: February 15, 2021, 11:39:57 pm
content: Saw this link in a time nuts post.https://www.sphere.bc.ca/test/stuffday.html#timefansThere some voltage reference ICs and an EDC millivolt standard among other stuff!Cheers,Corby

author: testpoint1
author_rank: Frequent Contributor
timestamp: March 02, 2021, 06:30:49 pm
content: I will have a 5065A soon, need to repair it.
Make your own probes for the Keysight Autoprobe Interface - Page 1
Forum section: electronics / general

author: Wolfgang
author_rank: Super Contributor
timestamp: March 11, 2021, 02:00:51 am
content: Hi all,I just enhanced my previously "dumb" Keysight Autoprobe adapters to incorporate the automatic detection feature using a built-inEEPROM. It works fine, so maybe its useful for others who want to attach homebrew special probes to a Keysight Autoprobe I socket.https://electronicprojectsforfun.wordpress.com/