hybridfree/eevblog-posts huggingface dataset:
HX711  Effective number of bits? - Page 1
Forum section: electronics / general

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: October 10, 2016, 09:21:03 pm
content: It's price under 1USD and it's marked as 24Bits, But I wonder what's the effective number of bits? there is not such parameter in the datasheet? How we could measure it?HX711 Datasheethttps://cdn.sparkfun.com/datasheets/Sensors/ForceFlex/hx711_english.pdf

author: EmmanuelFaure
author_rank: Regular Contributor
timestamp: October 10, 2016, 11:57:02 pm
content: https://forum.arduino.cc/index.php?topic=365107.0

author: splin
author_rank: Frequent Contributor
timestamp: October 11, 2016, 12:30:34 am
content: There's this thread too - they rated it as 12 to 14 bits accuracy but the tests didn't look to be well controlled (the soldering iron temp co test).https://www.eevblog.com/forum/projects/hx711-based-milliohm-meter/?nowap
Powering a REF IC with another REF IC - Page 1
Forum section: electronics / general

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: October 09, 2016, 09:14:50 am
content: HiDoes this idea give us some benefits? suppose we use a 5V ref IC to power a 2.5V REF IC? Does it increase the performance of the 2.5V reference?

author: Kleinstein
author_rank: Super Contributor
timestamp: October 09, 2016, 10:06:41 am
content: Having a stable supply for a reference can increase the performance. However with modern reference chips the supply does not have to be that stable. So no need (and no more significant improvement) to be better than standard regulators.Many circuits for shunt references even use the reference itself so set the current the reference is powered with.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 09, 2016, 10:09:17 am
content: Read the line regulation specs in the datasheets.My guess is that temperature and ageing are more significant factors.

author: David Hess
author_rank: Super Contributor
timestamp: October 09, 2016, 10:01:13 pm
content: It will increase the power supply rejection ratio but you can do the same thing by powering the reference from its own amplified output which is commonly done with zener diode references.
EDC 520A repair - Page 1
Forum section: electronics / general

author: feedback.loop
author_rank: Frequent Contributor
timestamp: March 29, 2016, 05:41:18 pm
content: I found this thing on eBay listed for $69.99, offered $40, and they accepted.I have not seen the following topic until nowhttps://www.eevblog.com/forum/buysellwanted/multiple-edc-520s-voltagecurrent-calibrators-on-ebay/Check out the repair video:https://youtu.be/pkMySlkpTJk

author: dacman
author_rank: Frequent Contributor
timestamp: April 01, 2016, 11:24:10 pm
content: If you try to control that unit from the IEEE, I would suggest using addresses 0-10. Address 16 (which is set in the video) is bugged on those units. Also, if the IEEE controller is fully 488.2 compliant, it will not send it commands due to the device not acknowledging its presence. You would need a controller that would send it commands anyway.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 02, 2016, 08:37:05 am
content: The BU208 look like they are not over-specified, but slight to weak in the SOA curve (at least with the old Siemens data-sheet I looked at). So with 150 V of DC at the transistor they might blow at more than 50 mA due to 2nd breakdown.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: April 02, 2016, 06:25:47 pm
content: Quote from: Kleinstein on April 02, 2016, 08:37:05 amI found schematics for EDC 522. The output amp seems to be identical to 521 on the first glance, but BU208A + 2N2219A in the output stage.http://www.ko4bb.com/manuals/24.23.183.55/EDC_522_DC_Voltage_Calibrator_Service_Manual_schematics.pdf

author: Muza
author_rank: Contributor
timestamp: September 24, 2016, 01:13:08 pm
content: Thanks again!Inspired by your repair video i decided to fix my two units. After following your repair log, the first one got fixed quite easily.Apart from the 2N5682 transistors you replaced, mine had a burnt MJE350 as well, so I replaced all three. On my other unit, two of these had a common 10K 5W resistor leading to them, which was charred. This exact resistor was missing on the unit under repair - not for longer though.Recapped the whole power supply, but the 5V digital rail kept dropping too low. The 5volt LM309K regulator has been tested to be okay. Rectifier bridges seems ok....refusing to deal with the transformer I just slapped an external 5V PSU hacked from 2A USB phone charger (HTC make).I realized that almost all of the OpAmps were OP07 to which I luckily had a better upgrade. I replaced these with five precision Burr-Brown OPA177 opamps.The second calibrator has a shorted primary on the transformer...so after all I might have to deal with winding one...Muza

author: SeanB
author_rank: Super Contributor
timestamp: September 25, 2016, 10:37:36 am
content: Scope on the input to the regulator will likely show a lot of ripple. Cure will be to change the rectifier diodes to ones with a higher current rating. Very common for rectifier diodes to fail long term by having an increased forward voltage drop under current, as the die inside cracks or breaks partly loose from the wire leads.
KVD comparison endeavor - Page 1
Forum section: electronics / general

author: VintageNut
author_rank: Frequent Contributor
timestamp: September 22, 2016, 05:08:03 pm
content: I recently added a Fluke 721A Lead Compensator to my volt nut rack.The rack has two KVD. A DV-4107 and a DV-4107D. It is now set up to compare one KVD against the other.The working hypothesis is that the newer model should be the reference divider.I have adjusted the 721A so that there is a zero reading on the null meter for LO and HI lead compensation.The voltage applied to the test is 10V from a Fluke 731B.Below are the results for the most significant decade of the KVDs where each comparison is a balanced null.Question: Is there an algorithm for checking a certain number of settings to be confident of the maximum deviation of the two KVDs?Any comments or suggestions are welcomed.DV4107 DV4107D999999X 999999X8999998 899999X7999997 799999X6999995 699999X5999995 599999X4999995 499999X3999994 399999X2999997 299999X1999997 199999X0999996 099999X

author: JS
author_rank: Frequent Contributor
timestamp: September 23, 2016, 05:17:43 am
content: check all the... 10^7 combinations??ok, maybe not.Maybe the 9 combinations 1111111 counts apart from each other? Half up/half down looking for the max "INL" or deviation? Get a girl? Maybe she helps you?JS

author: mycroft
author_rank: Regular Contributor
timestamp: September 23, 2016, 10:36:10 am
content: Try one of these references:- Calibration of a Kelvin-Varley Voltage Dividerhttp://ieeexplore.ieee.org/document/4313387/- Calibration of a Kelvin-Varley Standard Dividerhttp://ieeexplore.ieee.org/document/5006924/

author: VintageNut
author_rank: Frequent Contributor
timestamp: September 23, 2016, 11:46:02 am
content: Quote from: mycroft on September 23, 2016, 10:36:10 amThanks for the references. It looks like you have to pay for these articles.Anybody have a copy?

author: VintageNut
author_rank: Frequent Contributor
timestamp: September 23, 2016, 05:14:42 pm
content: Quote from: DiligentMinds.com on September 23, 2016, 03:01:37 pm
Help needed with calibrating my DIY Voltmeter - Page 1
Forum section: electronics / general

author: hillflyer
author_rank: Contributor
timestamp: September 23, 2016, 01:06:31 pm
content: Hello,I have built a compact, portable 6 digit Voltmeterusing a LT2400 ADC and a Max6350 reference.It has the input range of the LT2400, -0.1V to +5.1V.Who in Germany could help me with getting the thing calibrated against theirown 'proper' DVM?Kind regards,Hannesedit: the standard deviation value in the picture goes down to 2uV with shorted input

author: HighVoltage
author_rank: Super Contributor
timestamp: September 23, 2016, 01:41:51 pm
content: If you are in northern Germany, I can offer you a comparison to my many proper DMM, up to 7 1/2 digits.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 23, 2016, 01:55:19 pm
content: I'm also in northern germany (near Bremen). I have some calibration gear. A Fluke 5440B DC calibrator for example@HighVoltage: Where do you come from?

author: hillflyer
author_rank: Contributor
timestamp: September 23, 2016, 02:39:21 pm
content: I am in the south, near Augsburg,but I think I could package the little meter well and send it in the post.Hannes

author: acbern
author_rank: Frequent Contributor
timestamp: September 23, 2016, 03:10:47 pm
content: I am very close to you...And have calibrated standards.Send me a PM.
Got to play with the calibration machine today! - Page 1
Forum section: electronics / general

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 21, 2016, 07:59:02 pm
content: I bought a HP 3478A from EBay a few weeks ago. I had to fix the front panel to main PCB connection as some of the switches did not work. Of course it needed sticker goo cleaned off and a light cleaning. Is there some law that says the more stickers you plaster on a piece of equipment the better?I brought it with me to work today and got to learn how to use the Tektronix 5100B to calibrate my meter. We found the DCV, ACV, and ACA were all OK. Ohms and DCA were out of tolerance, the ohms most noticeably. The calibration procedure is pretty straight forward though and now it is 'bang on' accurateIt made for a nice break from my normal day...

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 22, 2016, 03:02:40 am
content: Yes, yes I do mean Fluke. After my co-worker showed me how to use the FLUKE 5100B and calibrate the meter we talked quite a bit about what a pain the Tektronix TM5000 series meters are to calibrate. We have a bunch of those in our teaching labs and they get the calibration checked after each semester. I must have had Tek on the brain after that
Need updated voltage check on AD588 10V Reference - Page 1
Forum section: electronics / general

author: enut11
author_rank: Super Contributor
timestamp: September 18, 2016, 07:26:54 am
content: I have a 10V reference based on an AD588 chip. I built the SC circuit about 6 years ago. Had it tested in Nov 2010. The output then was 10.0019V as measured on a calibrated HP3456A.After years in storage, I powered it up 3 months ago and it has been on ever since. I am now curious as to what the true output voltage is from an 'aged' chip.So, I am looking for someone with a calibrated meter of 6-8 digits to measure the output. I live in NSW, Australia, can post nationally and will cover return postage cost.Also after suggestions on boxing: is it worth transferring this circuit into a sealed plastic box?enut11
Datron Wavetek 1271 1281 self test question + details of successful repair - Page 1
Forum section: electronics / general

author: doktor pyta
author_rank: Frequent Contributor
timestamp: September 19, 2016, 05:43:11 pm
content: Is there some magic way of performing self test step by step ?This would be useful during troubleshooting.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: September 20, 2016, 04:34:04 am
content: There are many Pathway commands that can be accessed from the front menu. This gives you real time data while troubleshooting.There is mention of it in the 1281 service manual Section 2. I think the Pathway codes start with a P (ie P007)

author: doktor pyta
author_rank: Frequent Contributor
timestamp: September 20, 2016, 05:58:50 am
content: I missed that. Thanks!!!

author: doktor pyta
author_rank: Frequent Contributor
timestamp: September 21, 2016, 02:45:17 pm
content: Cut from EEVBlog Repair section:'I was a happy user of 1271 until yesterday.When I bought it I replaced internal battery. Everything was fine.It was passing full and fast self test without problems.After 3 days of constant work I noticed that AC measurement was not correct.What is more, the 100mV and 1V ACV ranges showed ERROR OL even with input terminals shorted.Also ACI on all ranges showed ERROR OL.After this self test shows multiple errors related to AC board.First I thought it is due to electrolytic capacitors, however the voltages and ripple were in reasonable level.I started tracking the issue. After some time i found a VERY strange defect: shielded reed relayRL104had shorted shield with the coil's terminal (two other relays don't behave like this). Fortunately I had such relays from old DATRON DMM. After replacing and cleaning all the area the AC measurement is correct again on all ranges. ERROR OL no longer apperars on ACI and ACV. One thing that is strange is that offsets in the AC measurement are significant (0,2V on 1kV range; 1mV on 100mV range).The self test ends with same errors as before the repair. It doesn't want to perform full self test, because it says it requires internal source calibration. When I run this internal source calibration it finishes with error related to ACV and ACI.P.S. DCV and RES functions work really good (stability <1ppm/3 days)P.S.2 I tried to perform AC calibration at 1kHz, I calibrated all ranges as described in the manual however I had no access to 1kV source. It didn't helped.Does anyone have similar problems?In what cases the internal NV RAM should be erased ?'My error codes were: 2342; 2322; 2312; 2422; 2432; 2472; 2492; 2512; 2632; 2622EDIT:the unit passes self test after repair.The reason of these errors were sticky relays type S2-24V. I had to replace 3 of themRL101, RL102, RL103.Bonus: photo of faulty components.
Agilent 6812A upgrade to 6812B - Page 1
Forum section: electronics / general

author: jgorsk
author_rank: Regular Contributor
timestamp: August 30, 2016, 09:51:21 am
content: Hi,Agilent used to offer the 14812A Upgrade 6812A to a RTS-ready 6812B. They don't do that anymore.Does anyone know what that was exactly, was it just the memory chip swap or were there hardware changesinvolved?Is an upgrade from the 6812A to the regular 6812B possible by upgrading the firmware?Does anyone has the 6812B firmware?
Fluke 845AR wet contact? - Page 1
Forum section: electronics / general

author: e61_phil
author_rank: Frequent Contributor
timestamp: August 09, 2016, 08:22:31 pm
content: Hi,today I opened my "new" Fluke 845AR. I had a look at the ZERO switch and it seems like these shorting contacts are wet. Is this normal or has anyone put some oil or something else on these contacts?Philipp

author: dacman
author_rank: Frequent Contributor
timestamp: August 12, 2016, 12:07:28 am
content: That is not normal. I'd blow it out with some canned (or compressed) air. If the switch is bad, I'd recommend using a burnishing tool on the contacts (clean the tool with IPA periodically). I would also wipe the burnishing tool with DeoxIT Shield and burnish the contacts, still cleaning the tool with IPA periodically (use only a thin layer of DeoxIT Shield).
Divider calibration artice, anyone have a copy? - Page 1
Forum section: electronics / general

author: VintageNut
author_rank: Frequent Contributor
timestamp: September 27, 2016, 03:47:17 pm
content: This is the title and authorA Method of Calibrating Standard Voltage Dividers up to 1000 VA. S. Katkov

author: awallin
author_rank: Frequent Contributor
timestamp: October 01, 2016, 08:41:42 am
content: Quote from: VintageNut on September 27, 2016, 03:47:17 pmyou have mail.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: October 01, 2016, 09:00:41 am
content: I have a scan of this (and other) publication, but in russian only.
Fluke 884X-SHORT youtube rant. - Page 1
Forum section: electronics / general

author: Macbeth
author_rank: Super Contributor
timestamp: August 20, 2016, 03:22:14 pm
content: Just found this. Thought you metrology guys would find it amusing!Apart from the obvious fail it's worth watching through his investigation. Warning. Do not be drinking coffee over the keyboard. I lost it when the microscope and calipers came out...

author: saturnin
author_rank: Regular Contributor
timestamp: August 20, 2016, 04:49:16 pm
content: The video is more than one year old - I only wonder whether he still believes Fluke (=masters in metrology field) made a bad design or he has finally found out what was wrong

author: Macbeth
author_rank: Super Contributor
timestamp: August 20, 2016, 08:49:42 pm
content: I actually thought this was some kind of April 1st thing as it was uploaded early April 2015. But he persists a few days later not realising what he did wrong...There's quite a treasure trove of EEVBlog-esque videos on his IEBlog channel, all ending with the familiar "if you liked this video please give it a thumbs up!"

author: Kleinstein
author_rank: Super Contributor
timestamp: August 21, 2016, 08:12:57 am
content: Whether you need have the arrow up/down or sideways depends on the layout of the terminals. This is a 4 wire short, but only good if the thin link is between the current driving and the voltage sensing termnal, not when mixing them. So there is a 50% chance to get it the wrong way around.There are special versions that allow to rotate them at will, more like a "perfect" star point. But this more difficult / expensive and not needed for a DMM.

author: Macbeth
author_rank: Super Contributor
timestamp: August 21, 2016, 10:54:53 pm
content: I would like to know why both Keithley and Fluke chose to use a very fine trace of copper between the sense and input terminals on their 4 wire shorting blocks instead of the same width tracks all around. Why not an X or a square? Also Keithley (8610/8620) have theirs right in the centre (like a H) while Fluke have their tiny trace (like a U)?Is the 12.5mOhm trace actually acting like the equivalent resistance of using normal Kelvin leads all shorted at the tip perhaps?

author: Kleinstein
author_rank: Super Contributor
timestamp: August 22, 2016, 06:20:54 pm
content: The thin trace makes sure that the contact between the current and voltage leads is really point like. Though its only important to have a point like contact, not that the line itself is thin. Just a full copper plane would not be a good zero ohms resistor.There is also a good thing in having a relatively large resistance when used the wrong way around: the 12 mOhms value is obviously bad, so one should note the wrong reading and turn the short. So if there is something to complain, it's more like that the 12 mOhms are not enough to make it obvious to everyone.
Using statistics on a 34465A? - Page 1
Forum section: electronics / general

author: carl_lab
author_rank: Frequent Contributor
timestamp: August 11, 2016, 10:30:17 am
content: Hi,I desperately try to show statistics on display of my new 34465A DMM.The only thing, that worked, is showing the histogram:Where are the fundamental values for average, min, max, span, std.-dev. etc...?I like the display on a 53220A counter:

author: carl_lab
author_rank: Frequent Contributor
timestamp: August 11, 2016, 10:38:30 am
content: OK, problem solved:Button "math", menu statistics/show.Sometimes I do not see the wood for the trees...
Smd Soldering with a Lamp - Page 1
Forum section: electronics / general

author: ebclr
author_rank: Super Contributor
timestamp: August 26, 2016, 04:26:41 am
content: Isn't so bad

author: zapta
author_rank: Super Contributor
timestamp: August 26, 2016, 04:57:01 am
content: Quote from: ebclr on August 26, 2016, 04:26:41 amNot great either

author: ludzinc
author_rank: Unknown
timestamp: August 26, 2016, 06:18:25 am
content: Quote from: ebclr on August 26, 2016, 04:26:41 amAny context? Might help.
Datron 1281 on ebay - Page 1
Forum section: electronics / general

author: BU508A
author_rank: Super Contributor
timestamp: August 04, 2016, 06:48:40 pm
content: Hi,there is a Datron 1281 for sale on ebay. Seller said, it comes with a DAkkS calibration certificate.No biddings yet (starts at 3500 EUR).Pity, seller will send this gear only to Germany.http://www.ebay.de/itm/282121828786Andreas

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 04, 2016, 08:39:03 pm
content: Thanks for that hint.Too expensive, though. Seems to be an accredited cal lab.4ppm DCV, 15 ppm 10kOhm, 50ppm Vac only.Not very promising for 1281 DAkkS calibration - Lab is not capable to do properly.I fetched several electronics kits (elektor) from Stolberg, I think, same road there, maybe 30 years agoOur daughter was born the next village.Anyhow, no deal for me.Frank

author: ap
author_rank: Frequent Contributor
timestamp: August 04, 2016, 11:13:05 pm
content: Well, the 15ppm you refer to in the add pictures is not the cal lab, its the meter spec. The cal lab uncertainties add to that. Good thing: the 1281, other than the 3458A, has the ohms transfer accuracy specified. But price, especailly with these options, is way too high.
Weird behaviour of BK Precision 2709B in capacitance measure mode - Page 1
Forum section: electronics / general

author: Schorsch
author_rank: Newbie
timestamp: August 10, 2016, 07:20:05 pm
content: I recently got my first decent DMM after watching the 100$ shootout video and decided on the 2709B. It works perfectly fine but seems to have a quirk.I tried the capacitance mode with 8 identical 1mF 50V electrolytic capacitors and the display would first say O.L. then jump to about 0.8mF and after another second drop down to 40?F. Then it goes to O.L. again and back to 0.8mF and it keeps repeating that cycle.I tested all 8 capacitors with the included probes and some extech probes and behaviour was the same. But only some of the time. It seemed that sometimes the orientation of the meter affected the stability of the measurment. So naturally I assumed the meter was busted and promply ordered a replacement from Amazon only to find that the new one behaves the same way.From that I excluded the meter, the caps and the probes as cause of the issue and fiddled around with my physical setup and found the following:Whenever there was some distance between the cables of the probes the measurment becomes unstable and when taped or wound together the measurment is rock solid.I figure the capacitance of the cables themselves must have something to do with it but the capacitance of only the leads varies between 30pF and 50pF depending on distance.Now that I know the cause of the problem I can avoid it, nonetheless it seems odd. Is this a common occurence? And what may cause it?
Is there a "cheap" replacement for Standard Capacitor sets like the HP 16380 - Page 1
Forum section: electronics / general

author: Tony_G
author_rank: Super Contributor
timestamp: August 05, 2016, 02:17:20 pm
content: Hi All,I know this is sort of like "Is there a cheap kit car replacement for a Ferrari" question but I thought I'd ask anyway. I have a HP 4275A that I'd like to try and see if it meets the original specs but the original specs call for a couple of these, very expensive on eBay at least, calibration standards.For this unit, the service manual is looking for 4 standard capacitance values 1pF, 10pF, 100pF and 1000pF - All at 0.01%.Any suggestions on what might be cost approachable replacements for these?TonyG

author: ebclr
author_rank: Super Contributor
timestamp: August 05, 2016, 03:56:56 pm
content: It's up to you trust or nothttps://world.tmall.com/item/36679253081.htm?spm=a312a.7700714.0.0.lfW5Pp
Connecting ps/2 keyboard to 3.3 volt fpga - Page 1
Forum section: electronics / general

author: rubenvann
author_rank: Newbie
timestamp: August 02, 2016, 10:50:07 am
content: I'm not sure if this is the appropriate subforum.I have a 3.3V FPGA, and I want to connect a PS/2 port to the GPIO. However, the keyboard needs 5.0 volt and 0.50 mA.I tried hooking it up to the GPIO directly, but the keyboard doesn't do anything (it works when I use a PS/2 to USB adapter to connect it to a PC). I might have the pins configured incorrectly, but I don't think I have. (However, the pinout of the PS/2 thing doesn't allow me to hook it up to the VCC and GND pins on the GPIO, so instead I do ps2_vcc_pin <= '1'; ps2_gnd_pin <= '1'; in my VHDL code, which some sources say is fine but I still want to mention it)As a test, I destroyed an old mobile phone charger which outputs 5.0V and tried attaching it to the ground and vcc pins on the ps/2. I figured that at least numlock should light up, but it didn't. I don't understand why, as this are, as far as I understand, the only pins that are inputs for the keyboard (or can the unconnected pins make some difference?).What is the easiest way to use the keyboard with my FPGA? There are some answers online, but they mainly suggest using a voltage divider while I can't figure out where the vcc and gnd should come from. I assumed they should be just 5 volt if 3.3 is not enough, but this doesn't seem to work.Apparently it's not, sorry. I'll open a new topic in the projects subforum.
Consult: May I ask 6L board can be changed to 4L board? - Page 1
Forum section: electronics / general

author: nail10
author_rank: Newbie
timestamp: June 30, 2016, 07:54:46 am
content: I take into account the original 6L is hit by the blind hole, to change 4L after the full to change through the hole?

author: Rerouter
author_rank: Super Contributor
timestamp: June 30, 2016, 08:28:34 am
content: Your going to have to better explain your question

author: PA0PBZ
author_rank: Super Contributor
timestamp: June 30, 2016, 10:19:12 am
content: My guess: It's about PCB's> Can you change a 6 layer board to a 4 layer board? It depends.And then something about blind vias.Not metrology at all.

author: nail10
author_rank: Newbie
timestamp: July 01, 2016, 06:21:36 am
content: I don't know how to put the circuit board six blind into four layers through holeQuote from: Rerouter on June 30, 2016, 08:28:34 am

author: nail10
author_rank: Newbie
timestamp: July 01, 2016, 06:23:34 am
content: Sorry, i am new member,not very understanding of this forumQuote from: DiligentMinds.com on June 30, 2016, 05:11:26 pm

author: nail10
author_rank: Newbie
timestamp: July 01, 2016, 06:24:56 am
content: i see,thank you for your educationQuote from: PA0PBZ on June 30, 2016, 10:19:12 am

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 01, 2016, 07:24:32 am
content: I've performed revisions on a lot of boards with more layers than they need. But maybe that one really needs it. No idea.Tim

author: wraper
author_rank: Unknown
timestamp: July 01, 2016, 07:46:17 am
content: Quote from: nail10 on July 01, 2016, 06:23:34 amThere is a typo in the link, try thishttps://www.eevblog.com/forum/eda/
Fluke meter lightning bolt?  Dangerous? - Page 1
Forum section: electronics / general

author: gooseEL34
author_rank: Regular Contributor
timestamp: June 26, 2016, 05:27:31 pm
content: Guysmy meter shows the lightning bolt (dangerous voltage present). I was troubleshooting a Bass Amplifier which had 30v rails and the bolt appeared. I work on tube amps usually having a B+ supply in excess of 400 vDC. I guess I am not being careful enough aroubd solid state amps. is 30vDC in a solid state bass amp deadly?

author: Kleinstein
author_rank: Super Contributor
timestamp: June 26, 2016, 07:35:21 pm
content: Many audio amps use dual supply. A single 30 V supply is usually safe, though in principle can become dangerous when really wet.It it's a dual +-30 V supply you should be more careful - that's about the legal limit from which on DC voltages are considered dangerous. So don't tough things on purpose, but not yet really dangerous - as long as you only touch one side.There are solid state amps with higher voltages (e.g. +- 60 V) too, if this is high power.The warning of the meter might come early, just in case, especially if it is AC voltage present at higher frequencies.

author: Lightages
author_rank: Unknown
timestamp: June 26, 2016, 10:12:36 pm
content: The general rule is when you get over 24VAC, or maybe 30VDC, you should start worrying about shocking yourself. This is based on how much current might pass through you body under worst conditions at this voltage. These are guidelines, nothing more. A 9V battery might kill you if you puncture your skin and pass the current from one hand to the other. Perfeclty dry and thick skin hands might be able to withstand 220VAC without killing you. It all depends.If a Fluke meter shows a danger symbol. it is best to start thinking about how you managing your safety. Nobody died from not touching the wrong thing.
Adjusting Quadrature Level on a 5200A - Page 1
Forum section: electronics / general

author: Tony_G
author_rank: Super Contributor
timestamp: October 11, 2016, 04:48:39 pm
content: Hi All,I thought I might finally try to adjust my 5200A and I'm doing the full list - I'm at 4-71 Frequency Accuracy and Quadrature Level Calibration.Para I. tells me to turn A2 & A3 in opposite directions to get an output of 9V-11V (I'm using a normal meter rather than a differential one on J65 if that matters) and nothing I do can get the level down to below 12.48V - Frequency I can get bang on to 800KHz.Is there another adjustment I've missed or does this level just matter to devices I may connect to the quadrature out (J65)? IF so then I can safely move on at this stage because I don't have anything to connect to that.Thanks,TonyG

author: Tony_G
author_rank: Super Contributor
timestamp: October 11, 2016, 04:55:35 pm
content: Well I just answered my own question on that I think - I attached a meter to the outputs to measure while I changed A2 and going from fully CCW to fully CW introduces about a 10mV difference in the output. A3 alone does a similar thing.Any suggestions on where to poke to bring that output down to spec? Or can I really just ignore it.Thanks,TonyG
2 Freq. Counters measuring - GPSdo's - Page 1
Forum section: electronics / general

author: bingo600
author_rank: Super Contributor
timestamp: June 04, 2016, 05:41:33 pm
content: This is a "fun" graphI have just got a HP 53132A w. opt10 (Thnx Steve) , and decided to do some tests.Red : PM6680B (Tbolt 10Mhz ext clk) - Measuring the 10Mhz out (10811 int. OCXO) from the HP 53132ABlue : HP 53132A (10811 OCXO int clk) - Measuring the 10Mhz out from my HP Z3801ABoth counters run frequency mode w. 1 Sec gate time.No doubt the 10811 OCXO in the HP 53132A is a bit high , and needs a bit of adjusting.No doubt the 10811 OCXO in the HP 53132A is a bit high , and needs a bit of adjusting.Well i just got a 3GHz prescaler card for the 53132A , and have a "Quiet" 12dB 9m3 fan waiting also.I'll adjust the OCXO when i do the 2 other mods.Now i regret not having routed the 1PPS from the Tbolt to the outside.I will have to do that , and start reading up on TI measuring on the 2 counters.But couldn't i do TI measures , by feeding the Tbolt 10MHz to "Counter Ext Ref In" , and also to "Chan 1/Start" , and then Z3801A 10MHz to "Chan2/Stop"I will prob try on all 3 counters : PM6680B , HP 53132A and HP 5370B./Bingo

author: bingo600
author_rank: Super Contributor
timestamp: June 04, 2016, 05:54:44 pm
content: OhhMy LED Magnifier lamp , creates spikes in the HP53132A readings when turned on/off.Prob. a "Lousy psu inside".Any "easy" hints to dampen the impact, preferably on the Led Lamp./Bingo

author: bingo600
author_rank: Super Contributor
timestamp: June 05, 2016, 08:06:30 am
content: Just had a quick glance @Service manual , and it seems that the "Real" Opt10 board has an onboard DAC.And can be calibrated via the menus.Is it possible to calibrate the TimeBase only ... wo. calibrating the interpolators ? - "Read anything but the interpolators"I don't have the equipment to do the "advanced" TI interpolator calibration./Bingo

author: TheSteve
author_rank: Unknown
timestamp: June 05, 2016, 05:12:37 pm
content: Yes, you can calibrate the timebase only and nothing else - it is very easy to do and even gives the instructions on the VFD.
Fluke 87 iii: full service manual - Page 1
Forum section: electronics / general

author: necessaryevil
author_rank: Regular Contributor
timestamp: May 29, 2016, 08:25:29 pm
content: Hello,I'm looking for the full service manual for the fluke 87 iii; all I 've found isthis34 page long document named 'service information'. This isn't the full service manual isn't it? Has anyone found it?

author: retiredcaps
author_rank: Super Contributor
timestamp: May 29, 2016, 08:40:53 pm
content: There is NO publicly available service manual for the 87 III and/or 87V. There is one for the original 87.What do you need the service manual for?

author: necessaryevil
author_rank: Regular Contributor
timestamp: May 29, 2016, 09:14:29 pm
content: Mostly: curiosity. Is there a non-publicly available service manual out there?

author: bdivi
author_rank: Regular Contributor
timestamp: May 30, 2016, 03:00:21 pm
content: Most test & measurement companies decided in the past decade to stop releasing schematics - Fluke including.I have a Fluke 187 myself and I was not able to find any meaningful technical information about it.One recent event however gave me hope. The long sought after schematics of the Tektronix TDS540A oscilloscope finality emerged despite statements from everyone that "it was NOT publicly available". I'm sure all those schematics are siting in someone's drawer and waiting to be scannedMy personal believe is that those companies can only gain customer loyalty by proving superiority of their products by technical documentation and schematics. I grew up with the HP Journals and Agilent/Keisight was and still is the king partly because of this sharing.

author: necessaryevil
author_rank: Regular Contributor
timestamp: May 30, 2016, 05:00:03 pm
content: It appears that the companies are afraid to give away their knowledge. Anyway, it didn't came as a surprise for me that Agilent/Keysight still has public documentation, they seem to recognize the importance of 'the 'community'. The stuff they have sent to Dave might be a good example, and I've also came across a tear down video made by Keysight themselves.

author: zlymex
author_rank: Frequent Contributor
timestamp: May 31, 2016, 03:57:12 am
content: Looking at my files, I found this 108-page 'Fluke_83_85_87_Service_Manual.pdf' with schematics.It is not 87 iii but may be used as a reference. I cannot remember how I got that but seems to be genuine and not private.Edit: I've just realized that this manual is publicly available.

author: retiredcaps
author_rank: Super Contributor
timestamp: May 31, 2016, 04:04:37 am
content: Quote from: zlymex on May 31, 2016, 03:57:12 amThe original 87 service manual is right on Fluke's website ...http://assets.fluke.com/manuals/83_85_87smeng0500.pdf
agilent u1273ax out of calibration after 8 months - Page 1
Forum section: electronics / general

author: Wolfram.Chrome2
author_rank: Newbie
timestamp: May 17, 2016, 05:47:56 pm
content: As my title says the agilent u1273ax of mine friend is gone out of calibration after he's buy it 8 months ago.The problem is not very big ,because he's able to get an replacement with another new for free.However im doing this thread ,becasue i've also heard some years ago that Agilent's DMM'S love's to go out of calibration after a very short time of their operative life.(in this case it was happen after 8 months)So is this true or just some cases when Agilent's DMM'S really like to go out of cal after short time??Or this is only some cases which can happens around the world ?Im asking this (dumbass question for you ,but interesting for me) because i was willing to buy for my self the same multimeter of my friend (agilent u1273ax),but after this case im a little bit scared ,also because i've never heard about this kind of problems on Fluke's,Hioki,Wavetek,Brymen ecc ....

author: Wolfram.Chrome2
author_rank: Newbie
timestamp: May 17, 2016, 05:50:05 pm
content: 5vdc was = 4.88310vdc was = 9.79812vdc was = 11.938

author: wraper
author_rank: Unknown
timestamp: May 17, 2016, 06:18:48 pm
content: This is not out of cal but obvious fault in the circuit.

author: Wolfram.Chrome2
author_rank: Newbie
timestamp: May 17, 2016, 06:22:40 pm
content: Quote from: wraper on May 17, 2016, 06:18:48 pmWhy you are so sure ,he told me that other functions are working properly .

author: wraper
author_rank: Unknown
timestamp: May 17, 2016, 06:37:14 pm
content: 2.5% off is not "functions are working properly" when spec for 30 V range is 0.05% + 2 digits. And cannot be just calibrated to meet the spec again. Also there is noticeable nonlinearity.Quote from: Wolfram.Chrome2 on May 17, 2016, 06:22:40 pm

author: Wolfram.Chrome2
author_rank: Newbie
timestamp: May 17, 2016, 06:38:46 pm
content: Thanks .
Experience with/alternatives to Fluke Met/Cal? - Page 1
Forum section: electronics / general

author: guy48065
author_rank: Newbie
timestamp: May 06, 2016, 02:07:38 pm
content: My employer recently bought me a new Fluke 5522A calibration standard and Met/Cal to bring my lab up to date with more automation. I have no prior experience with Met/Cal and I'm not a programmer. My experience so far is you MUST be a programmer to use this program! My efficiency has plummeted since I started scaling the vertical learning curve of building a database, finding and/or modifying procedures, and modifying the report templates.What other calibration programs communicate with instruments and standards and are easier to use than Met/Cal?

author: guy48065
author_rank: Newbie
timestamp: May 07, 2016, 04:40:03 pm
content: Ok I'm new here...there's not many Metrologists in the metrology section?

author: TiN
author_rank: Super Contributor
timestamp: May 07, 2016, 04:45:51 pm
content: Most of us are hobbyists, doing stuff at home, so not many of local members here used MET/CAL thing.Why you have to be a programmer? There are number of procedures on Fluke's website for use with 552X MFCs and various instruments, should be rather plug'n'pray experience...Perhaps if you can share some specific questions, someone can help you out with details.

author: guy48065
author_rank: Newbie
timestamp: May 09, 2016, 04:21:41 am
content: Quote from: TiN on May 07, 2016, 04:45:51 pmThere are many hundreds of procedures available...and one of the reasons there are so many is the procedure itself sets all the parameters for the calibration. Which instruments you have, which version of the UUT is to be calibrated, whether you need error calculations to display on the report , etc. You'd expect such minutae to be chosen by the interface, but Met/Cal is rather behind the times so the operator must make changes & choices via code.Really just looking for an alternative to Met/Cal.

author: quarks
author_rank: Frequent Contributor
timestamp: May 09, 2016, 07:48:22 am
content: so far I only played around with Wavetek Portocal, but it is obsolete and you need a hardware dongle (which I unfortunately do not have).Therefore my own first choice would be Fluke MET/CAL.For alternatives I would have a look at:Transmille PROCALTime Electronics EasyCal

author: guy48065
author_rank: Newbie
timestamp: May 09, 2016, 05:10:14 pm
content: Transmille: I did "test drive" this last year. Does comply with ISO 17025 requirements re uncertainties, but very limited support of US instruments. Maybe in years to come...Gossen: (1) Only supports Gossen. (2) It's a data acquisition platform, not calibration software.Time: I've sent an email inquiry to answer the following: (rather sketchy that these things are omitted on the site)Support for uncertainty display on certificates? (website hints it's all manually calculated, no examples)List of supported instruments & standards.

author: acbern
author_rank: Frequent Contributor
timestamp: May 10, 2016, 08:17:42 am
content: Anybody experience with Surecal? (Northrup Grumman)Looks interesting on paper, but awfully expensive.
Fluke application note about DMM test / calibration - Page 1
Forum section: electronics / general

author: Dr. Frank
author_rank: Super Contributor
timestamp: May 31, 2016, 06:25:05 am
content: Fluke just has sent me a nice application note: "A generic DMM test and calibration strategy".It can be found here:http://us.flukecal.com/node/19698This AN describes the basic building blocks of a DMM, and how to verify its performance.I used such a procedure, to evaluate the 34465A/470A, and to identify the errors of the 100V/1kV DCV ranges.https://www.eevblog.com/forum/testgear/keysight's-new-34465a-(6-5-digit)-and-34470a-(7-5-digit)-bench-multimeters/msg889215/#msg889215Frank

author: Mickle T.
author_rank: Frequent Contributor
timestamp: May 31, 2016, 11:55:39 am
content: Ain't the same?

author: Dr. Frank
author_rank: Super Contributor
timestamp: May 31, 2016, 03:03:05 pm
content: Recycled, obviously, as Fluke recycles many DMM stuff from Wavetek / Datron.Frank

author: enut11
author_rank: Super Contributor
timestamp: June 01, 2016, 06:32:55 am
content: Quote from: Dr. Frank on May 31, 2016, 03:03:05 pmThanks for sharing. It was a good bedtime read...
Synchronisation of data from tools made by different (big) companies - Page 1
Forum section: electronics / general

author: rgawron
author_rank: Contributor
timestamp: April 18, 2016, 08:54:28 pm
content: Let's say that I have a FLK-8845A and U1231A or U1731C, I want to make a plot of values from both of those two devices in one graph. No programming, no payed software. What if I would like to include data from USB-6002. Is it possible? What software should I use?

author: 6thimage
author_rank: Regular Contributor
timestamp: April 19, 2016, 07:56:17 pm
content: If you want to use devices from multiple manufacturers, most people will point you in the direction of labview or matlab, but these are both commercial and not particularly cheap either.Personally, I like to use python for ethernet or USB devices, for ethernet it is easy to set up, usb is a little more difficult. The only downside is that you have to read through the user manuals and get used to using scpi, but you can set up what ever test system you like without paying a penny.Unfortunately, any decent software you will want to use will be expensive and you don't stand much chance of finding open source alternatives, so rolling your own is what's left.
Radioshackus - another GPSDO dealer from China... - Page 1
Forum section: electronics / general

author: Turbon
author_rank: Regular Contributor
timestamp: April 07, 2016, 05:17:25 pm
content: My unit built on the Trimble base doesn't seem to work as stated - tested. I followed the pdf connecting it and typed help... - No response from the unit. The unit when powered on with the antenna connected started with the leds On and Alm1 - after one second the On moved to Lock -and have stayed there since.Sorry, I was overly harsh here so I decided to edit it. There is an solution to this I'm sure of. Will look into it during the weekend.One small problem is for us in Europe - the insert for the wall is as seen for US - so another cost wil be a travellers convertion or the quest of finding an insert for that wallwart for different holes in the wall:).Regards

author: Turbon
author_rank: Regular Contributor
timestamp: April 07, 2016, 06:09:20 pm
content: This was not worth reading... Sorry if I upsetted anyone hereRegards

author: Gyro
author_rank: Super Contributor
timestamp: April 07, 2016, 07:20:44 pm
content: You seem really worked up about this, I see that you posted the same thing over on diyAudio.Are you saying that it's just the serial communication isn't working? It sounds as if it is locking, have you tested the frequency outputs?If it's just the serial port then it may be a genuine fault or a connection error, baud rate or other problem. It doesn't sound like a scam to me.

author: Fraser
author_rank: Super Contributor
timestamp: April 07, 2016, 07:35:24 pm
content: That GPSDO has been reviewed on this forum and from what I read it does work. The RS232 port does not, IIRC provide access to the GPS in the way that is found on a Trimble Thunderbolt.I personally use a pair of genuine Thunderbolt GPSDO's and love themI will try to find the appropriate thread for you and supply the link in a minute.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: April 07, 2016, 07:37:14 pm
content: Here is the thread.....https://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/

author: acbern
author_rank: Frequent Contributor
timestamp: April 08, 2016, 12:48:00 am
content: As a general remark, I am not sure it is fair to kind of blackmail (another China guy...; and not only on this forum as Gyro points out) this seller at a point where he has not even been able to respond or sort this out. Things may go wrong, any supplier may have DOA units, and he may (or may not) be very helpfull to sort this out. We do not know yet.I think sellers, especially at this point of an issue, should be treated in a fair manner, and I dont think it is the case here, this is how this comes accross to me.

author: Turbon
author_rank: Regular Contributor
timestamp: April 08, 2016, 05:49:08 am
content: Point taken - thank you.I am in peace with the seller. He is very helpful. The unit works fine today.Regards
UT61E fuses in the US - Page 1
Forum section: electronics / general

author: donf99
author_rank: Newbie
timestamp: April 04, 2016, 08:40:09 pm
content: Hi, all! My first post. I'm a telecom engineer for the past 35 years. I've been getting along with my trusty Fluke 77 series I meter for more years than I care to think about! It still works perfectly, but I wanted sonething with a bit more capability to support my ham radio, RC aircraft and planespotting hobbies. I settled on the UT61E as a great value meter. I Looked long and hard at another Fluke, but just couldn't bring myself to part with the cash for the one I wanted.I was very pleased with the meter when it arrived, $45.00 USD from Amazon! It seems to have undergone some circuitry updates since the flurry of interest a few years back. I hooked it up to my multiple reference voltage source from China...right on the money on all the ranges I was able to check.While fooling around with current measurements, I popped the 1A fuse. I thought it would be no problem to pick up a fuse locally here in the US. Wow, was I wrong!! The fuses are a BS1362 type with a 6x25mm form factor. These are apparently common as dirt in the UK, but almost impossible to find in the US. I ended up ordering a bag of 30 of each value from Hong Kong. I ordered a few TDC180's from DigiKey to get me by until then. They are ceramic with the same form factor. I am not sure if either type is sand-filled, but the TDC180's are rated to interrupt up to 6000A at 240 volts.Has anyone found a good local source in the US for these fuses?? Not tgat I'll be needing one, but...I liked this meter so much that I ordered a second.Thanks and regards,Don

author: Towger
author_rank: Super Contributor
timestamp: April 04, 2016, 09:05:19 pm
content: Just order them from ebay.co.uk. Chances are the HK fuses will be fakes and have no sand and the same thickness fuse wire for all values.Edit: I think your TDC180s may be the same thing.

author: donf99
author_rank: Newbie
timestamp: April 05, 2016, 06:09:20 am
content: I didn't realize fake fuses were so prevalent. There are quite a few articles on this. I'll have to break a few of the HK units open and run some tests when they arrive.I think the DigiKey TDC180s should be OK, though, although country of origin is China. They were $2.00 each, so hopefully that buys some assurance of a genuine item.Are the BS1362 and TDC180 used interchangeably in the UK? The TDC180 spec sheet is here:https://www.digikey.com/catalog/en/partgroup/tdc180-series/4551?mpart=BK/TDC180-10&vendor=283Best,Don

author: Towger
author_rank: Super Contributor
timestamp: April 05, 2016, 07:46:27 am
content: BS 1362 is short for British Standard 1362 and should have the 'Kitemark Symbol' printed/stamped on it. But the fakes will have the all the correct codes on them as well. Only a couple of weeks ago I saw and bought a packet of Bussmann branded fuses at a large discount store chain and they were fakes. This is from a large company which should know better.I had a look at the data sheet on Farnell and the TDC180 is the same.