hybridfree/eevblog-posts huggingface dataset:
AGZ1000 reference board day of judgement (Fixed ltz1000 size) - Page 1
Forum section: electronics / general

author: sahko123
author_rank: Frequent Contributor
timestamp: July 03, 2022, 06:34:08 pm
content: As the PPM virus continues coursing through my blood I've designed an LTZ1000/A board based on the circuit by xDevs/Illya but with a pcb of my own design. I've attached the gerbers below for people to use if they wish.https://drive.google.com/file/d/1FxJANjkAT5FnrGvwpLpCjUjesq7qjHxn/view?usp=sharingThis is my first ref board design and am yet to receive and evaluate it but once I do I'll update here. here are some photos of the board front and back. If anybody has any questions or think I've done something wrong/could have done better I would love to hear.

author: TiN
author_rank: Super Contributor
timestamp: July 03, 2022, 08:16:59 pm
content: You forgot to include two handles to carry that huge LTZ of yours.P.s. package looks "little" big.

author: sahko123
author_rank: Frequent Contributor
timestamp: July 03, 2022, 08:33:35 pm
content: Yep ffs kicad works in radius not diameter.Thanks for spotting that otherwise I would have cried when it arrived

author: sahko123
author_rank: Frequent Contributor
timestamp: July 03, 2022, 09:33:53 pm
content: Maybe you're just jealous because my ltz is bigger ( ͡° ͜ʖ ͡°)......Here's the new image with the life size ltz1000

author: Andreas
author_rank: Super Contributor
timestamp: July 04, 2022, 07:18:43 pm
content: Hmm,I am missing any buffer for the output voltage of the reference.In case of a short cirquit on the output this may lead to a quick degradation of the reference.I usually have jumps of -5 ppm after such a (short) event on my unbuffered LTZ1000A.with best regardsAndreas

author: sahko123
author_rank: Frequent Contributor
timestamp: July 05, 2022, 08:36:19 am
content: I did consider adding a seocndary buggered output but eventually thought against it at least because if the way it would be used.The plan was to use it as a mezzanine board where it then goes onto whatever needs the reference such as a 7.15 to 10v gain stage or 7.15 to 5v divider. And that would reduce the risk.And with this pin layou will in future have up to 3 or 4 different references using it such as the ltz1000/a, adr1000, adr1001 and possibly the 1399 so that they can all be used with minimal mods in my upcoming voltmeter based in the ltc2500-32

author: iMo
author_rank: Super Contributor
timestamp: July 05, 2022, 08:45:50 am
content: Mezzanine board - I would definitely increase the number of pins in your headers.2 + 2 is desperately low number for that kind of headers/contacts (and it is an "ultra.." device), imho.Something like 8+8 (or more) will lower the total contact resistances and increase the signal integrity, moreover it gives you more mechanical stability too..

author: sahko123
author_rank: Frequent Contributor
timestamp: July 05, 2022, 02:02:50 pm
content: Mezzanine board may have been a bit of an exaggeration I meant more of a plateu board if that makes sense. Where instead its flat against the motherboard.
Help with multimeter siglent sdm3045 o 3055 - Page 1
Forum section: electronics / general

author: Cristian82
author_rank: Newbie
timestamp: June 13, 2022, 07:41:54 pm
content: How about colleagues, good afternoon, I'm wanting to buy an sdm3055 multimeter but I saw a video on youtube where these measurements come outthe one on the right is 3045 and the one in the middle is 3055, I want it for cell phone repair,In the diode scale, some instructions mark me 2v, but they say that there are some updates since in cell phones the voltage drops mark us up to 2,700vin some instructions it tells me that it has up to 2v in others that from 2 to 4v I want to know if someone has one to help me with that questionSomeone who has this equipment that can help me a little with some doubts in advance thank you very much

author: RikV
author_rank: Regular Contributor
timestamp: June 13, 2022, 10:01:44 pm
content: I am not sure about the 3045 or 3055, but the test voltage in dioderange is adjustable to 4.000V on my SDM3065. That must be documented in the specification sheets. Pretty sure it is adjustable also on 3045 and 3055. 3065 is certainly good stuff for the money!

author: bateau020
author_rank: Frequent Contributor
timestamp: June 22, 2022, 12:51:14 pm
content: SDM3055 here:continuity: up to 6V test voltage, 1mA test current, beep threshold adjustable 1Ohm to 2kOhmdiode: up to 6V test voltage, 1mA test current, beep threshold adjustable 1mV to 4VNo possibility to force a lower test voltage or test current.

author: GigaJoe
author_rank: Frequent Contributor
timestamp: July 07, 2022, 03:57:34 am
content: multimeter counts voltage how it lookssdm3045 66000 V2.1234 V4.1234sdm3055 240000 V2.12345 V4.1234i may suggest 40000 or 50000 , 60000 counts handheld multimeter , the cheapest one would be HP-770D 42000 counts.to measure battery voltage basically 1mV resolution enough to catch charge\discharge, an it would be the multimeter at least 6000 counts (that a lot on market, like cheap aneng an8008) , but still 42000 to 50K 60K would be better, but definitely handheld.
Lady Heather GPS  - Page 1
Forum section: electronics / general

author: mkube396
author_rank: Regular Contributor
timestamp: June 23, 2022, 11:11:48 pm
content: ok some thing is not right I'm New and I'm lost.I'm not seeing any gps satellites and its just saying Self Survey in progress 1%

author: chuckb
author_rank: Frequent Contributor
timestamp: June 24, 2022, 12:05:43 am
content: What type of GPS receiver are you using?It looks like you are running version 5.0 of LH.The latest version, that I know of, is version 6.14. See below for the link.Quote from: ve7xen on October 01, 2020, 02:28:46 am

author: tkamiya
author_rank: Super Contributor
timestamp: June 26, 2022, 01:08:52 am
content: LH is looking at COM2. If you start some kind of terminal program and read off COM2, do you see series of lines? Try 4800 bps and 9600 bps. What kind of GPS is this? Often, you have to tell it what it is, although LH will do its best to try to auto-determine it.

author: rockwell
author_rank: Regular Contributor
timestamp: June 26, 2022, 05:42:39 pm
content: I think COM is configured right, Trimble part numer from this board is shown (57964-60).Maybe you can show the command line you are using, there must be something wrong with it.

author: mkube396
author_rank: Regular Contributor
timestamp: June 27, 2022, 10:47:08 am
content: the top one is 6.14 the lower one is 5.0.it is communicating fine. this is a GPSDO it is a 10Mhz Freq standard that locks to the GPS sats to lock a 10mhz OCXO Oven Controlled Crystal Oscillator.it finds a UCCM receiver when loading up Lady Heatherill have to find a terminal program windows 11 don't have one ill try to plug this is to my older windows XP computer

author: ch_scr
author_rank: Frequent Contributor
timestamp: June 27, 2022, 01:57:00 pm
content: Htermis my terminal tool of choice for stuff like this.
HMP4040 User interface - Page 1
Forum section: electronics / general

author: Baltazar
author_rank: Contributor
timestamp: June 23, 2022, 06:24:09 pm
content: I am thinking about acquiring a R&S HMP4040 power supply. Can anyone with user experience answer this:1. How can you independently turn a given channel's output on & off? The manual states:The Output key turns on the outputs of all activated channels and supplies the connected loads.This is not clear to me - which are the "activated channels"? "Activated" doesn't mean "output on", right? Can you e.g. turn Ch1 output on, then turn Ch2 output on as well, and then turn Ch1 output off while keeping Ch2 output on? What would be the keypress sequence for that? And how to turn e.g. Ch1+Ch2+Ch3 outputs on & off at the same time? I want to check if the UI is intuitive enough.2. Can you at any moment clearly see which channels' outputs are on are which are off? I would think the "Ch1"..."Ch4" key illumination indicates this but again according to the manual:Selecting the channels► Press the channel key, e.g. Ch1.An active channel key is illuminated in green.So the light goes on when the channel is activated, not when the output goes on.

author: Baltazar
author_rank: Contributor
timestamp: June 23, 2022, 07:18:19 pm
content: I see "Test Equipment" is a better place for this question so I copied it there. But I can't remove it from here:You cannot delete your own topics in this board. Check to make sure this topic wasn't just moved to another board.
ESI SR104 spare parts available - Page 1
Forum section: electronics / general

author: manganin
author_rank: Regular Contributor
timestamp: June 14, 2022, 04:43:38 pm
content: Genuine SR104 parts:2x handle8x rubber footThese could possibly be leftovers from an SR104 oil bath conversion, but that is just a guess. I got them from a military lab a long time ago. Good condition, considering the age.For free to good homes. Except the postage of course.But "send them all to me" doesn't work here, because my goal is to cure as many patients as possible. So post a picture of your crippled SR104 and tell what is missing.Not for test equipment dealers etc. These are not for sale, please don't offer money to be the first in the line. Active metrology forum members only.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: June 14, 2022, 05:36:05 pm
content: I have two missing the leatherette handle.I am not greedy and would be happy with one.

author: ap
author_rank: Frequent Contributor
timestamp: June 15, 2022, 11:45:24 am
content: Hi,mine does have an aftermarket (and not well fitting) handle. Also, the feet are pretty hard, not elastic. That makes placing it on the table a little bumpy. So if your feet are elastic, I would be interested in these too, if not then they seem to be designed that way and I would not need them.So if you want, and if I am not too late, would be nice.Am in Germany. Am on travel the next few days, so may not be able to respond before Saturday.I can have it picked up by UPS at your place.Also, if you have a resistor or so to calibrate, I could do as compensation of your efforts.ThanksAdrian

author: manganin
author_rank: Regular Contributor
timestamp: June 16, 2022, 03:50:47 pm
content: Both handles seem to have found a new home. (Except one pair of those chrome plated end covers, because ManateeMafia already has them.)And to keep the process transparent:post your needs here, please no private messages.Quote from: ap on June 15, 2022, 11:45:24 amNot brittle hard but not soft either. I don't know if they were different at the time of manufacture 50 years ago. Or is it just that the modern materials are so much better.

author: MiDi
author_rank: Frequent Contributor
timestamp: June 16, 2022, 07:18:58 pm
content: Quote from: ap on June 15, 2022, 11:45:24 amThe feet look likeKeystone 728.They are medium hard/bit elastic, got them for my K236/7/8.

author: HighVoltage
author_rank: Super Contributor
timestamp: June 17, 2022, 08:43:06 am
content: Quote from: MiDi on June 16, 2022, 07:18:58 pmThese Keystone feet work well on old equipment and they look like they belong on these old units. Also they stick a little to the table and do not slip. I have installed them on several old Keithley instruments.I have been looking for years for a good used ESI SR104 but either they are far too expensive or in bad shape. And it seems more and more people are looking and that makes the hunt not easier.

author: manganin
author_rank: Regular Contributor
timestamp: June 24, 2022, 10:12:08 am
content: Both handles posted today.
Waketek/Fluke 9100 parts needed - Page 1
Forum section: electronics / general

author: jsolomonsc@gmail.com
author_rank: Contributor
timestamp: July 05, 2022, 09:57:10 pm
content: Does anyone have an old wavetek 9100 that has a front bezal you are willing to part with or willing to send to me to have 3d scanned?I have a functional unit that need a front bezel.

author: ebclr
author_rank: Super Contributor
timestamp: July 06, 2022, 03:33:31 am
content: Do you know the value, and size of this instrument?You will need a very helpful änyone" to send you a big and expensive piece of hardware, which normally is used to make high amounts of money on calibrations, just to you scan the bezel?Perhaps Santa Claus has a lab.

author: Echo88
author_rank: Frequent Contributor
timestamp: July 06, 2022, 07:42:29 am
content: Theres certainly a higher chance for him to be lended a bezel by someone, than for you to get good manners from Santa Claus.

author: Testtech
author_rank: Regular Contributor
timestamp: July 06, 2022, 10:33:54 pm
content: You might contact lowthermal.com. I think they may be remaking the Wavetek calibrator front bezels.
Fluke 5520 A unstable VDC output - Page 1
Forum section: electronics / general

author: tavisho
author_rank: Newbie
timestamp: February 01, 2022, 09:38:46 pm
content: Greetings, this is Octavio from Mexico. We are experiencing some trouble with our Fluke 5520 A. For starters, it showed Error 104 Trip Relay and was solved by replacing a 9 volts regulator. Currently, the 5520 A is performing poorly and we are obtaining unreliable VCD readings, oscilating between +- 0.5% of reading, wich for a 5520 A is a lot. Also, when turning off and turning back on the calibrator the reading will not remain stable. Any suggestions?Does anyone have schematics for this device? thanks in advance.

author: Ugur
author_rank: Regular Contributor
timestamp: June 08, 2022, 08:36:19 am
content: Hello,Can you share the diagnostic test and Zero test results?
DAC linearity test. 16/ 12 bits. - Page 1
Forum section: electronics / general

author: MasterT
author_rank: Frequent Contributor
timestamp: July 04, 2022, 01:43:17 am
content: Was playing with MCP3561R module, and discovered that ADC has exceptionally good linearity - THD below -130dB.Testing was done with AC & FFT, so next move would be to verify using DC voltage. I get my best DAC's out of shoe box and put them in quick test - 400 pixel (dots) than differential between ADC readings and LMS line. Results may not be accurate on vertical scale - 16ppm actually 32ppm - I used resistive divider to get 5V into 3.3V ADC range. But there is some impressive surprise with dac80501 I get, that may be interesting for others , so decided to share.
Azonix A1012 RTD thermometer - Page 1
Forum section: electronics / general

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 17, 2021, 12:55:39 am
content: Below a teardown of the thermometry readout built like a tank equipment.I had no luck with finding A1012 manual or schematics, but found out that Omega DP95 is a re-branded Azonix A1011.Fortunately DP95 manual is compatible with A1012 with some minor differences. The same with GPIB commands.The readout provides four galvanically isolated independent channels measuring in 0...320 ohms in 4 wire connection.Excitation current is approx. 2mA. No offset compensation.Advanced configuration can be performed via GPIB or attachable front panel (which I don't have, but I learned how to skip that).This front panel uses small magnet to trigger the Hall effect sensor to enter configuration mode.In my case this Hall sensor occurred to fail (!). Fortunately it has open collector output so I temporarily use parallel switch.My unit has 3rd channel modified by the manufacturer.If someone has any more info on these or similar readouts please post or PM me.

author: Vgkid
author_rank: Super Contributor
timestamp: April 17, 2021, 03:22:07 am
content: Thanks for the teardown. I own the smaller model , the A1011Enclosed is the analog board.

author: chuckb
author_rank: Frequent Contributor
timestamp: April 17, 2021, 04:53:03 pm
content: I have several A1011s and A1012s. I am using an A1012 to monitor the temperature of my L&N resistors in a (5 US gallon) oil tank. A Lakeshore 330 controls the temperature of the tank.This document from the US Army provides some calibration help for the A1012.http://electroniccalibrators.tpub.com/TB-9-6685-331-50/TB-9-6685-331-500001.htm

author: Ikwam
author_rank: Newbie
timestamp: March 28, 2022, 12:34:21 pm
content: Hi Sir, Good day to you.Can you/someone help me if any of readers know the output pin configuration or schematic diagram for the RTD thermometer AOnix A1012/A1011/A0113? Please help.Thank you in advance.

author: zorktronics
author_rank: Newbie
timestamp: May 27, 2022, 03:48:57 pm
content: I'm also looking for the A1011 detailed instructions to configure the 4 channels after some repairs were done, if anyone has the 2864 binary or the manual it will be of great help to get some valid configuration data.
Nortel GPSDO - Page 1
Forum section: electronics / general

author: Wazza
author_rank: Contributor
timestamp: May 09, 2022, 10:26:47 pm
content: Hi all,I've recently received a Nortel GPSDO (the big card as used in base stations) and all five lights (the circle, triangle, square, lock and holdover) turn on when I power it up from 48V dc. However they stay on and don't turn off.There is no response from the unit when I use GPSmon to try and talk to it. From what I can find out it appears to be stuck in a diagnostic mode.Can anyone help please?Waz

author: tkamiya
author_rank: Super Contributor
timestamp: May 10, 2022, 03:26:13 pm
content: I have many of those Nortel units.Firstly, how are you expecting to turn it off, since there is no power switch? If you cut the power, the unit will stay on until capacitor discharges completely. I've never experienced having no response from GPS mon. Are you sure polarity of TX and RX is correct? What happens if you swap it? Have you tried just a plain terminal?

author: Wazza
author_rank: Contributor
timestamp: May 10, 2022, 10:57:30 pm
content: Some clarification:When I power the unit all five leds turn on, including the GPS and the HOLDOVER leds. The gps antenna is NOT connected. From what I've read at least some of the leds should turn off after approximately 15 seconds, but they don't. All the leds are still on after half an hour. Further reading suggests the unit is stuck in a diagnostic mode and that the firmware might have been trashed. I don't know how to confirm or deny this.I have connected an SMA adaptor to the gps socket and proved I have 5V on the socket, as my gps antenna is active (and will accept 3 to 5V dc input).The paperwork I have leads me to believe the 9 pin female connector on the front panel, next to all the SMB connectors, should plug into a pc serial port with a straight through cable. I've not tried a crossover cable. I'm using a windows 2000 sp4 pc with a real serial port (not a usb dongle) and I've confirmed the pc port and cable works.Waz

author: tkamiya
author_rank: Super Contributor
timestamp: May 16, 2022, 08:13:47 am
content: I'm going from (fading...) memory.I think it is correct that your serial cable is straight through. Mine was setup like that. One thing I remember is, it took long time to establish the very first lock. It remembered the old location, and I had to force it to survey and recognize it has been moved. I don't remember the command I used though.
Relay leakage question - Page 1
Forum section: electronics / general

author: julian1
author_rank: Frequent Contributor
timestamp: June 06, 2022, 09:34:18 pm
content: Consider a relay (rated 10^10 Ohm insulation resistance) with a coil switched by an open-collector opto-coupler with RIO=10^12 isolation resistance, and an isolated power supply/winding. Will current leakage from relay coil pin to pole pin be limited to 10^12 ?When off, some dark current flows through the collector/emitter of the bjt, and extra darlington if present. But because the supply is isolated, I don't see a possible path for any voltages present on the relay pole pins.

author: TimFox
author_rank: Super Contributor
timestamp: June 06, 2022, 10:06:36 pm
content: Draw the equivalent circuit:The relay spec means > 1010resistance from either relay pole to the relay coil.The coupler spec means > 1012resistance between the output side of the isolator and the input side.One more resistance: what is the resistance from the isolated power supply to ground, and to any power supply voltage?Besides ohmic resistance across the transformer, there may be substantial capacitive coupling of the mains voltage.That will contribute to the resistance from the relay coil to everything else (including the isolator input).The off current of the bjt should be too small to affect the position of the relay poles.

author: julian1
author_rank: Frequent Contributor
timestamp: June 06, 2022, 10:21:19 pm
content: Yes, I was thinking a very high-isolation transformer / or separate transformer would be needed. But maybe possible with a secondary coil wound on a separate split bobbin section of an EI core former, or unused section of a toroid.What I am not sure about is transformer capacitive coupling for the supply. And if that would make for a DC path.It does seem like a lot of complication.

author: TimFox
author_rank: Super Contributor
timestamp: June 06, 2022, 10:32:30 pm
content: The winding-to-winding capacitance of the transformer may be important if you worry about 50/60 Hz, but it will not give you DC leakage.Since power supplies are macroscopic, the leakage resistance to ground, compared with 1012, may not be negligibly high.

author: free_electron
author_rank: Super Contributor
timestamp: June 06, 2022, 10:52:29 pm
content: And then you put them on a pcb contaminated with greasy finger goop, flux remnants , drool and whatnot. after 5 years the pcb has collected so much dust it's ready to catch fire.
L&N low-thermal-emf switch cleaning - Page 1
Forum section: electronics / general

author: TimFox
author_rank: Super Contributor
timestamp: May 11, 2022, 08:50:30 pm
content: I have three of these beautiful, classic, Leeds & Northrup switches.They seem to use hardware similar to the "low-thermal-emf binding posts" from L&N used in my Keithley 260 Nanovolt Source.The body is real bakelite, and the metal is some kind of copper, not plated, possibly Be-Cu (?).They are are a bit old, but in good condition.What cleaning product and technique are recommended for the switch metal parts?I don't want to use an abrasive, but I also want to ensure the surfaces are free from copper oxide, which has a high emf against copper.The photo was taken above a 0.5" grid.

author: MK
author_rank: Regular Contributor
timestamp: May 11, 2022, 09:31:55 pm
content: The contacts will be pure copper, use brasso or similar to remove the oxide, and then ipa or similar to remove the last traces of the brasso.

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 12, 2022, 02:57:25 am
content: Bon-Ami powder available in the cleaning materials isles should remove the oxides without scratching the base metal, it’s straight feldspar without any abrasives added as you might find in other scouring powders.I’d just rinse well with di or distilled water.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: May 12, 2022, 07:44:35 pm
content: They must travel in threes, as I also have three. A couple are missing the knobs. They're excellent switches and I've used them for winding resistance/temperature measurements. It took my coworkers a bit of time to get over the size!
HP53132 inaccuracies at or near 10MHz - Page 1
Forum section: electronics / general

author: tkamiya
author_rank: Super Contributor
timestamp: May 02, 2022, 03:27:07 pm
content: I did my best to search everywhere but can't find it.It is known that HP53132/53131 counters have degraded performance at or near clock frequency which is 10MHz. This is noted by HP somewhere. The question is WHERE? I've seen it myself but I can not find it now. Not in user's manual, not in service manual, or at least I can't find it. Can someone point me to it?Thank you.

author: mycroft
author_rank: Regular Contributor
timestamp: May 02, 2022, 03:34:13 pm
content: Take a look athttps://www.febo.com/pipermail/time-nuts/2017-December/108226.html.

author: tkamiya
author_rank: Super Contributor
timestamp: May 05, 2022, 06:21:20 am
content: Thank you. That is it!
HAMEG HMF2525 Low CR2032 battery - Page 1
Forum section: electronics / general

author: blackdog
author_rank: Frequent Contributor
timestamp: April 27, 2022, 03:54:29 pm
content: Hi,One of my function generators is a HAMEG HMF2525 which is almost identical to the HMF2550 and is about 12 years old.These generators have a CR2032 on the digital board and my CR2032 has a battery voltage of just above 3V.My question is this, can I just replace this battery?Or will I then lose e.g. calibration data ore other data, I know the system has an autocal, but I can find very little data regarding the memory that keeps this battery powered.Should the battery be replaced under voltage, for example, which I would find a bit strange, etc.?Do any of you have experience with replacing the CR2032 battery in these function generators?ThanksKind regards,Bram

author: max-bit
author_rank: Frequent Contributor
timestamp: April 27, 2022, 04:18:08 pm
content: Probably the service manual for this does not exist on the network.You would have to analyze what this battery powers.take a picture of the PCB in its vicinity ... let's see what's sitting on the PCB over thereWhat is the voltage of this battery (exactly)

author: blackdog
author_rank: Frequent Contributor
timestamp: April 27, 2022, 06:48:09 pm
content: Hi max-bit,You want me to start up my 3458A to indicate that the battery voltage is 3.025678V and then communicate this here....3.02V is about it and to me that means the battery is at the end of its life after 12 years of use.I had of course already done a search, but there is damn little technical information to be found of these generators.Also in the latest manual I downloaded today from RS, I could not find anything about replacing the CR2032 battery.I have three other function generators, so I can just try it, and if it goes wrong, too bad....Reverse engendering doesn't seem like a good idea to me, is going to take way too much time, with the chance of something breaking.I'm in no hurry to do this, so wait a few more days to see if some one has more information. and will report here how it went.o be sure.I am also going to copy the "Device Settings" to a USB stick, just te be shure, and will report here how it went.I can tell that the generator is nicely built, nice PCBs and well shielded power supply.The internal coax cables are of the Teflon type.Thank for the replyRegads,Bram

author: MK
author_rank: Regular Contributor
timestamp: April 27, 2022, 08:14:30 pm
content: The manufacturers put the end voltage at about 2.2-2.8 volts, the exact lower limit is driven by the chips that it powers, I am sure that 3.02 is still on the mostly flat portion of the curve.

author: max-bit
author_rank: Frequent Contributor
timestamp: April 28, 2022, 04:41:23 am
content: 3.02 is good
Electronic Load. Constant Resistance mode, but spec is in Amps, W - Page 1
Forum section: electronics / general

author: ttttrigg3r
author_rank: Contributor
timestamp: April 22, 2022, 09:24:44 pm
content: Electronic load CR mode. This spec sheet says that the accuracy is in Amps? I'm not getting it. If I set Constant Resistance Mode for 100Ω, shouldn't the tolerance be based off of that and in Ohms?

author: tszaboo
author_rank: Super Contributor
timestamp: April 22, 2022, 09:55:29 pm
content: The CR more is software calculation. They read the voltage on the terminal, and set the current setpoint. So the specification of it ultimately depend on the current range.

author: alm
author_rank: Super Contributor
timestamp: April 22, 2022, 10:03:27 pm
content: This is common for electronic loads. If you look atthis Kikusui datasheeton page 8, they describe the accuracy as the "current conversion" accuracy: given an input voltage of 12V, how close is the current it will sink to 12V/R (what it should sink according to Ohms law). That's why the uncertainty is given in amps.
3458a relative accuracy/offset immediately after calibration - Page 1
Forum section: electronics / general

author: Fidel
author_rank: Contributor
timestamp: April 04, 2022, 02:01:29 pm
content: Immediately after performing a zero and DCV calibration on one of our 3458as opt2, we witness anywhere from a 0.4-1uv offset from the calibration value. Let's say we enter in CAL 10.0000054 with a Fluke 732 as the source. After cal is complete, it reads 10.0000060-65. I do understand that this is within the 10min 0.5+0.5ppm transfer spec, but compared to our other meters they're usually spot on right after cal. We repeated zero and DCV cal with similar results. We did just install a new A3 board and the machine has been running for a week.What is the experience of others? Thanks

author: HighVoltage
author_rank: Super Contributor
timestamp: April 05, 2022, 08:12:13 am
content: In my experience the entered value will stay stable after the calibration.You have a good quality short that will not produce any EMF?How big is the zero offset after calibration is completed?What happens if you run a ACAL DCV after calibration?

author: Fidel
author_rank: Contributor
timestamp: April 18, 2022, 02:18:11 pm
content: In our experience also, hence our surprise with the offset. We used a solid 2mm piece of c101 copper wire as a short, waited for 5mins for temps/emf to stabilize. With the 732 still connected after CAL 10, The offset is almost exactly 1uv. Autocal dcv or auto all retains the offset. OhmsF with the short still connected reads 0.0000 and dcv 0.0009mvOhms calibrates and reads spot on.Another interesting phenomenon is while using it with ratio on, the measurement is unstable. Shorting the inputs to each other should be a near perfect 1 but i see 999.9997m-1.00000012 which makes me think there may be something with the switching going on -Could Q14 be leaking?
Wavetek 9100 Procedures? - Page 1
Forum section: electronics / general

author: Arhigos
author_rank: Regular Contributor
timestamp: May 02, 2022, 06:10:27 am
content: Hi all. I have wavetek 9100 calibrator that i want to use under remote control. It seems that my calibrator is having PCMCIA memory card slot for external procedures which can allow me doing calibration without computer connected. But i cannot find any procedures or procedure writing manual.Does anyone know how i can write those procedures? The calibrator datasheet pdf tells me that i can generate custom procedures in Portocal-II software (but i was unable to find any download link and wavetek website was down long time ago). Maybe someone knows where i can find calibration software, or at least any sample procedure?

author: dl1640
author_rank: Regular Contributor
timestamp: May 12, 2022, 10:37:49 am
content: I had this idea many years ago, and asked Fluke, they do not recommend so.- You must have PCMCIA Type I card- You may need Win 95 PC for running the software- I suppose the procedure written only controls 9100 and with user interaction (e.g., ask for user input for hand-held DMM cal)So, back in the day, I wrote a program in VB6...But for fun, you are encouraged to try, we've been switch to 5502A for years.
General Radio 1454-A divider VER2 - Page 1
Forum section: electronics / general

author: jonpaul
author_rank: Super Contributor
timestamp: April 08, 2022, 02:06:01 pm
content: Bonjout a tous...I bought another SN is 4462, $60...later style different engraving, ribbed case sides, very fine condition, missing logo badge...1/ All four decades have the very tight rotation and soft detents. old lube in shafts congealed?I Forgot the drill to fix that, type of solvent, lube or adjustment for the shaft?2/ for Museum display restoration,Missing the metal red GR logo badge, ~ 10 x 13 mm ....Anyone with a source or spare from an old GR donor....(:-:)3/ Seems GR specs changed over the years...Comparing 4462 to SN 1973, I used Keysight 34465A as differential 10.000 Vref on both.Has anyone compared same or similar pairs of voltage dividers?Mille MercisJon

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: April 08, 2022, 05:08:36 pm
content: Yes, needs clean and relube. I don't know of a source for those logos, as there are more missing than there is supply. Never tried it but if it were driving me crazy I'd probably draft one up and print it on good photo paper. Then I'd coat it with a heavy layer of resin to look similar to the original.

author: jonpaul
author_rank: Super Contributor
timestamp: April 08, 2022, 06:14:05 pm
content: Dear Conrad, as always welcome your wise council ....Looking at all my GR stuff, a few have those logos but cant bear to sacrifice a 1390 noise gen....many of the old GR have engraved GR TM but no red logo....To free up the shafts, used spray Rite Off tuner cleaner plus....big improvement, detent also better.To lube the shafts, just oil?The contacts seem fine... it just the mechanical. Some green corrosion spots on the shaft, otherwise very clean inside....Kind Regards,Jon

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: April 09, 2022, 04:07:04 pm
content: My go-to lube these days consists of three things. 1) Superlube grease with PTFE (PAO base, fumed silica "soap" and 5 um PTFE particles). Good for shafts, switches and pretty much anything where you want something longer lasting than oil. Good as a contact lube. 2) Superlube Synthetic Oil with PTFE (PAO based, with 5 um PTFE particles). Use anywhere but sintered bearings. 3) Superlube Lightweight Synthetic Oil (PAO based but no PTFE particles). I use this on high precision instruments and in sintered (Oilite) bearings. All should be safe for most plastics, but check compatibility charts if available.
Leeds and Northrup 86962 millivolt meter - Page 1
Forum section: electronics / general

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: April 07, 2022, 01:02:40 pm
content: Leeds and Northrup 86962 millivolt meterJust picked up one of these as a lark. Looks pretty good inside and out except the batteries are corroded and battery terminals need some care.I have trouble finding a manual. This thing has a Weston Cell in it. Ca I measure the cell with an HP 3456??Wally

author: alm
author_rank: Super Contributor
timestamp: April 07, 2022, 01:38:56 pm
content: The 3456A should have an input impedance of > 10 GOhm in DCV ranges up to 10V, so that should be fine to measure a Weston cell if you set it to manual ranging just to be sure it doesn't switch to the 100V range.
3458A and SNAPHATS - Page 1
Forum section: electronics / general

author: Grandchuck
author_rank: Super Contributor
timestamp: April 05, 2022, 04:18:32 pm
content: My user defined key programming was lost due to a dead cell in a SNAPHAT. Luckily, the calibration data were OK as the other SNAPHAT had a little life left. It wasfortuitousthat the non-critical cell died first.I found MJLorton's video () to be helpful. I ordered replacements from DigiKey (part# 497-3690-5-ND). They arrived quickly and appear to have been manufactured in 2020.The video mentioned 48 mAh parts. I am wondering if that was because his unit had been repaired? It seems that the 120 mAh parts would/shouldalwaysbe supplied by Agilent/Keysight?The replacement process is straightforward ... do be sure to have the DMM powered on to maintain the calibration.Many thanks to TiN for the information on his website and the link to the video!
TEMEX(now Spectratime) MCFRS-1 Rubidium Oscillators. - Page 1
Forum section: electronics / general

author: hgl
author_rank: Regular Contributor
timestamp: April 04, 2022, 12:49:03 pm
content: I have 9 Temex Rb MCFRS-1, of which 4 are good and 5 are bad. These oscollators could be ordered with up to 4x10E-11 / per month drift. The best one I have (serial number 1265) could fortunately be one of these.Some interesting documents and Adev, from the best I have (SN: 1265), against a Samsung UCCM-L8 GPSDO.

author: hgl
author_rank: Regular Contributor
timestamp: April 04, 2022, 01:11:43 pm
content: The Case

author: hgl
author_rank: Regular Contributor
timestamp: April 04, 2022, 01:14:04 pm
content: The physics ...

author: hgl
author_rank: Regular Contributor
timestamp: April 04, 2022, 01:25:57 pm
content: electronics part 1 ...

author: hgl
author_rank: Regular Contributor
timestamp: April 04, 2022, 01:27:48 pm
content: electronics part 2 ...

author: hgl
author_rank: Regular Contributor
timestamp: April 04, 2022, 01:44:29 pm
content: Monitoring of the startup process via RS232 from a good and a bad Rb.
FS: Valhalla 2500EN Current Calibrator in the UK - Page 1
Forum section: electronics / general

author: perdrix
author_rank: Frequent Contributor
timestamp: April 02, 2022, 09:08:18 am
content: https://www.ebay.co.uk/itm/284736721489It's the high impedance version of the 2500EP and it's trivial to convert one to the other (there's a page in the manual that has the details).For the avoidance of doubt, I'm the one selling it.Cheers, David
General Resistance DAV-46E voltage reference  - Page 1
Forum section: electronics / general

author: jonpaul
author_rank: Super Contributor
timestamp: March 24, 2022, 12:30:27 pm
content: Bonjour à tousJust acquired this vintage "Dial-A-Volt" thumb wheel 1/10V référence for $65.In very fine condition, but simple 1N827 low TC Zener reference is unstable and out of cal adjustment trimpot is pinned.In the schematic, I can find similar DAS series but not any DAV, and DAS 46 without E suffex. DAV series may have no chopper stabilized opamp.the power supply is different.Want to fix and calibrate, then to upgrade the amplifier and reference.A manual or schematic pdf of DAV-46E will he greatly appreciatedMille mercis pour votre gentil aideCordialementJon

author: bastl_r
author_rank: Regular Contributor
timestamp: March 29, 2022, 06:43:50 am
content: Hello jonYou are a lucky guy.Some years ago, when i was serching for schematics of my ETS15 i found a manual from the DAV Series.Here in the attachment it is.Holy... Its tooo big. 26MB.So i loadet it tomy datagraveYes its in russia, but i have this folder since more than 12 years because sharing others.ragards

author: jonpaul
author_rank: Super Contributor
timestamp: March 29, 2022, 09:36:59 am
content: Bastlr! WOW perfect, MANY THANKS!this confirms what I had suspected that the DAV 46E has no chopper opamp, it is just a reference and KV divider.After realizing the polarités and 1V 10V switches were scratchy, I just used contact lube and the 10V was stable, I could calibrate with the Keysight 34465a to 10.0000Running an overnight stability trend now.Enjoy,Jon
OMNICAL 2001 - Page 1
Forum section: electronics / general

author: Glenn-WB4UIV
author_rank: Newbie
timestamp: March 27, 2022, 04:11:46 pm
content: Does any one have operating/service info on an OMNICAL 2001-D Voltage Calibrator?I have one I would like to use and the company that made it is unresponsive to requests for info.ThanksGlenn
FA2 plus frequency counter - Page 1
Forum section: electronics / general

author: Picuino
author_rank: Super Contributor
timestamp: March 18, 2022, 09:33:31 pm
content: I was trying to buy a BG7TBL FA2 frequency counter on e-bay and the seller asked me if a new model (FA2 PLUS) would work for me instead of the old one.I don't know this model. Is it new? Is it better than the old model? Does anyone know it?

author: mankan
author_rank: Regular Contributor
timestamp: March 19, 2022, 06:43:52 pm
content: Search amongTony Albusvideos and I think you will find the details.

author: Picuino
author_rank: Super Contributor
timestamp: March 20, 2022, 07:07:54 pm
content: I know Tony Albus, but I haven't found this counter in his videos.
Constant Voltage on a DC Electronic Load. What power supply to use? - Page 1
Forum section: electronics / general

author: ttttrigg3r
author_rank: Contributor
timestamp: March 11, 2022, 07:55:31 pm
content: This is a little confusing to me, perhaps one of you fine people can help.I have a GW Instek PEL-3032E DC Electronic load. It has a Constant Voltage mode which clamps the voltage at whatever setting. Is it possible for me to use an autoregulating power supply such as HP 6032? The power supply switches between CV and CC mode automatically, so I cannot force it in one mode.So now I'm having the load and the power supply kind of fighting each other. Not sure what to do here.https://www.gwinstek.com/en-global/products/detail/PEL-3000E

author: Kleinstein
author_rank: Super Contributor
timestamp: March 11, 2022, 08:13:14 pm
content: In constant votlage mode the electronic load is a kind of high power precision zener diode. So it can consume excess current, but it does not provide power.The power would need to come from an external supply, e.g. as a constant current source.A usual lab supply could be set to a votlage slightly higher than the load voltage and would thus be in CC mode all the time.Still chances are the lab power supply would be better in providing a constant voltage and the power consumption is usually lower. The electroinc load version would allways take the maximum power.

author: ttttrigg3r
author_rank: Contributor
timestamp: March 16, 2022, 06:46:33 pm
content: Thank you!I tried this. Here's what I learned.You want your PS voltage to be slightly higher than the load. Here slightly higher means exactly that... My PS voltage setting was 20V, 1A. The load UUT setting is CV, 19.5V. This setting however trips the load over current protection for that range, which is 1.5A. I think the load is trying to draw higher current to make up for that gap.Next I set the load UUT setting at 19.9V. This voltage gap between the load and PS is smaller than before. Now, it works as expected. The Load is clamping at 19.9V and current reading is ~.8A. I also see that the power supply engages Constant Current (CC) mode. I adjust the PS current output from 0.5A to 1.5A, and the current draw of the load follows the adjustment accordingly. The voltage stays at 19.9V the whole time.
Balanced/unbalanced isolation balun usage with 10MHz ref. clock distribution - Page 1
Forum section: electronics / general

author: HalFoster
author_rank: Frequent Contributor
timestamp: March 14, 2022, 01:21:01 pm
content: All-I have several Mini-Circuits baluns (BNC, 1:1, unbalanced:balanced) and am wondering what the correct way to integrate them into a 10MHz reference clock distribution system would be. First of all, I would think that they would not be necessary to begin with since all equipment connected is in the same rack and the power (and ground) is all on one circuit and no more than 10' from distribution amp to the equipment. That being said though, what *would* the correct usage? Would they go on the amplifier or the equipment side of the cable? Which side gets the balanced and which the unbalanced. Does it matter or there advantages one way over the other? Both the amps and the equipment BNC connectors share a common ground but for the sake of argument say that they don't. In one instance that will actually be the case since I will be going about 60' from one building to another. The amplifiers will be HP 5087As as well as possible a Brandywine FDA-1050 both of which have grounded outputs.TIA,Hal

author: jonpaul
author_rank: Super Contributor
timestamp: March 14, 2022, 01:55:24 pm
content: Legnth of cables? # loads? Zo 50 or 75 Ohm? Source voltage, Zo?Jon

author: HalFoster
author_rank: Frequent Contributor
timestamp: March 14, 2022, 02:43:07 pm
content: Length: under 10' for all except one - that one 60' all 50 ohm coax with BNC connectorsSingle 50 ohm load each1.5V RMS

author: jonpaul
author_rank: Super Contributor
timestamp: March 14, 2022, 04:39:51 pm
content: What mini ckt part #?Why balanced if all TX/RX and cables are unbal /BNC/coax?TX....trsf...cable...trsf..RXFloat one or both BNC shields off the chassis use 47 pF RF bypass if needed.See my previous post re passive 10 MHz house master clkJon
ESI AC/DC Generator/Detector 865A - manuals, schematics? - Page 1
Forum section: electronics / general

author: meandeev
author_rank: Regular Contributor
timestamp: March 11, 2022, 07:48:49 pm
content: I know there are a lot of people here who like the ESI stuffI got a ESI 865A "as is" but had to find out that someone was in (and destroyed traces with bad soldering skills and so on).So I´m looking for a service manual, schematics etc. but didn´t found anything in the usual places.anyone?edit: added some photos

author: Stray Electron
author_rank: Super Contributor
timestamp: March 11, 2022, 08:01:53 pm
content: No idea. But based on the name it sounds like it might have been part of an ESI Impedance Bridge. Have you looked into that? I know that there were several generator/detectors available for the ESI 250 DA bridge. They were all of a similar design but used different value components and were designed to operate at different frequencies. But the 250 service manual lists the value of all of the components of the different model generator/detectors. If you can find what ESI model used the 865A then that manual may at least give you the component values.

author: meandeev
author_rank: Regular Contributor
timestamp: March 13, 2022, 04:00:14 pm
content: yes, it seems to be designed to be a part of an ESI bridge (see first post, I uploaded some pictures).But I didn´t found a bridge documentation with that part. Also the ESI250 is completely different.

author: manganin
author_rank: Regular Contributor
timestamp: March 14, 2022, 08:38:35 am
content: Quote from: meandeev on March 11, 2022, 07:48:49 pmSearch for "ESI Impedance Measuring System".The problem is that so many versions of the generator-detector was made. The passive bridge section didn't change, but the evolution in active electronic components was fast.
Daven WW resistor - Information wanted - Page 1
Forum section: electronics / general

author: kleiner Rainer
author_rank: Regular Contributor
timestamp: March 11, 2022, 09:12:27 pm
content: Greetings,while rummaging through Dads basement I found a circuit board with 26 precision resistors made by Daven, type 1195. The values range from 127 Ohm to 450kOhm, the tolerances from .375 to .5%. The construction style hints to a wirewound resistor. I found a patent assigned to Daven with construction details that seem to fit the resistors I have:https://patentimages.storage.googleapis.com/2c/96/ae/d6601c265796e3/US3012216.pdfAnybody got a data sheet or catalog page with more detailed infos?Greetings,Rainer

author: jonpaul
author_rank: Super Contributor
timestamp: March 12, 2022, 10:48:45 am
content: Fine usa made equipment used similar from Dale, Allen's Bradley Daven in 1940s..1970s. Very common, probably metal film not WW.Just sacrifice one, scraped off outer coating tomsee resistive elements.We have boxes of them.Jon

author: Kleinstein
author_rank: Super Contributor
timestamp: March 12, 2022, 12:19:16 pm
content: There are notches visible at the top / center and bottom. So this could well be wire wounds.A first point would likely to just test 1 or 2 to see how stable the resistors are with temperature. If they don't perform well, one may not have to worry about the details.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 12, 2022, 03:54:20 pm
content: Daven made a lot of wire wound resistors. Not sure they made anything else. Do a Google image search on daven and resistor to see a bunch of examples and some old advertising.

author: kleiner Rainer
author_rank: Regular Contributor
timestamp: March 12, 2022, 05:55:59 pm
content: Google search only found early amplifiers and Nipkow disk TVs made by the Daven Corporation. Searching for a combination with "1195" found something similar:https://aerobasegroup.com/part-number/1195-10k_00-060-6342Dimensions: check. Power: check. Part number: check. Resistance: different.So those Daven 1195 seem to be noninductive wirewound resistors with a +-20ppm temperature coefficient. I measured 150uH at 1kHz with my RCL meter - low enough for a wirewound resistor. If I am bored, I will try to measure tempco.Greetings,Rainer

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 12, 2022, 08:40:34 pm
content: https://www.google.com/search?q=daven+resistor&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjBmMKWt8H2AhX2kIkEHWR0AmoQ_AUoAnoECAEQBA&biw=1920&bih=937&dpr=1See what this shows under images.

author: TimFox
author_rank: Super Contributor
timestamp: March 12, 2022, 09:12:04 pm
content: Around 1965, Daven was known mostly for their audio attenuators (suitable for broadcast and mixing boards) and high-quality rotary switches.Back in 1960, when the corporate fashion was to buy totally unrelated companies to show diversity of business, they were bought by General Mills, to complement their Cheerios.In 1976, they were acquired by Shallco (who had previously acquired Shallcross switches and attenuators) and merged thereinto.