hybridfree/eevblog-posts huggingface dataset:
Decreasing the DSO sampling rate (intentionally) - is there a way ? - Page 1
Forum section: electronics / testgear

author: roli_bark
author_rank: Regular Contributor
timestamp: May 13, 2013, 04:49:48 am
content: Is there a method to decrease a DSO sampling rate intentionally so that longer capture window times can be achieved [at one-shot capture mode] ?For example, given a 1Mb/s max digital data input, and a 1G Sa/s scope with a 100Mpts memory depth.A one shot capture at full memory depth will span a 100ms time window.Is there a way to intentionally decrease the sampling rate to, say, 10M Sa/s (which is enough for sampling a 1 Mb/s data), and with the same memory depth get a span x100 (1G Sa/s / 10M Sa/s) folds more - e.g. 10 Seconds ?

author: amspire
author_rank: Super Contributor
timestamp: May 13, 2013, 05:14:47 am
content: Quote from: roli_bark on May 13, 2013, 04:49:48 amThe scopes adjust the sampling rate to suit the timebase speed and the capture memory size.For a particular scope, it depends on the scope firmware. Here is the way the firmware of a Rigol DS1052E is set for sample rate versus timebase settings + memory depth).https://www.eevblog.com/forum/blog/rigol-ds1052e-sample-rate-vs-timebase-setting/msg115617/#msg115617Other scopes have a different formula. Hate to say it, but it is a case of reading the manual for a particular scope.In general, the answer to your question is "Yes".

author: roli_bark
author_rank: Regular Contributor
timestamp: May 13, 2013, 05:21:26 am
content: Thanks. I'm ashamed to say - yes, I did not.I'm a newbie at this, and didn't get yet the chance into looking deeply at my scope user manual.Thanks again,
Fluke 25 Multimeter Overview (Video) - Page 1
Forum section: electronics / testgear

author: TheEPROM9
author_rank: Frequent Contributor
timestamp: May 12, 2013, 12:13:33 am
content: Here is a video I did over viewing the Fluke 25 Multimeter, it was a lot older than I first thought =-)Oh yes I compare it to the Maplin Precision Gold PG10B multimeter.Link:http://youtu.be/RRe6WhKm5Ts
need cal procedure for the HP3478A - Page 1
Forum section: electronics / testgear

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 10, 2013, 07:42:17 pm
content: heyI have got any standard needed , just don't know the procedure , can someone instruct me ?I've rotated the "Cal" rotary swich and the letter "C" is now on screen , then I pushed the shift and thee "cal" buttons , then the device ask " 10.0000 ? " and from there I don't know what's nextthank you in advance !

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 10, 2013, 07:47:21 pm
content: Did you bother to read the manual?

author: mikes
author_rank: Regular Contributor
timestamp: May 10, 2013, 07:50:05 pm
content: go to agilent.comunder "Electronic Test & Measurement", click on "Manuals"Find "3478a" using the search boxDownload the Service Manual (you may have to register)Calibration starts on page 4-11 (section 4-48)(you really should have full cal instructions in front of you, and read them, before you start setting things into cal mode)

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 10, 2013, 07:50:27 pm
content: the menual is long and I understood that there are few ( I am shure I am wrong but that's my impression)

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 10, 2013, 08:39:27 pm
content: thank you mikes , I've tweaked the meter and now it reads down to the LSD ( compare to fluke 5700 )
Tektronix 5111A - Page 1
Forum section: electronics / testgear

author: G7PSK
author_rank: Super Contributor
timestamp: May 09, 2013, 02:32:05 pm
content: I have seen a Tektronix 5111A Storage with 5A18, 5A22N and 5B1n plugins is this a good scope to have, I am not sure if it has cursors and readouts which is some thing I would like on the next scope I get, also what sort of money are they worth.

author: robrenz
author_rank: Super Contributor
timestamp: May 09, 2013, 03:06:28 pm
content: AFIK the 5A22N is the same as the 7A22 which is a very nice differential amplifier that goes to 10µV/div. Google the manual on the 5A22, I think you will be impressed.

author: G7PSK
author_rank: Super Contributor
timestamp: May 09, 2013, 03:22:32 pm
content: As far as I can tel the scope is only 2Mhz band width I have 40 Mhz with the old National that I have at present or is the bandwidth set by the plugins.

author: robrenz
author_rank: Super Contributor
timestamp: May 09, 2013, 03:56:30 pm
content: Wow, I could not find any manuals for the 5xxx series

author: G7PSK
author_rank: Super Contributor
timestamp: May 09, 2013, 05:14:47 pm
content: Lots of info here.http://w140.com/tekwiki/wiki/Main_PageI also managed to download a pdf of the main instruction manual but for some reason it fails to upload onto the blog.

author: robrenz
author_rank: Super Contributor
timestamp: May 09, 2013, 05:53:49 pm
content: My apologies if you already sawthis postof a 7A22 amplifier at 10µV/div measuring PS ripple. These amps are only 1 MHz bandwidth anyhow.

author: SeanB
author_rank: Super Contributor
timestamp: May 09, 2013, 06:37:45 pm
content: I have one, and yes the manuals are as rare as rocking horse. Not the storage one, just the 5000 mainframe, and a 5A19 and 5B10 plugins. The 5A19 diff amp is a very nice plugin to use, you just do not have to worry about grounding issues at all with it as long as you keep in the CMRR limits. I want the 5CT1N plugin though, that will be very nice to get. Good for audio, and worked well on lower frequency digital devices.
Rigol DSA815 Programming Guide bad? - Page 1
Forum section: electronics / testgear

author: zener
author_rank: Contributor
timestamp: May 08, 2013, 12:20:41 pm
content: I downloaded the programming guide for my Rigol DSA815 from their web site.After I unzip it I get DSA800_ProgrammingGuide_EN.chm. Windows 7 opensit as a HTML Help file. I can see the table of contents but the actual pages aremissing. I can navigate the table of contents OK but all of the actual pages are blank.The other instruments programming guides are PDF files but this one is different.Has anyone had any luck with this? Is a PDF file available?Thanks,Pete.

author: Rufus
author_rank: Super Contributor
timestamp: May 08, 2013, 01:32:26 pm
content: I have a copy downloaded from somewhere some time ago.880,319 bytes MD5sum isc1e19e02c977136004338247d673b5da *DSA800_ProgrammingGuide_EN.chmSeem to be functional.

author: zener
author_rank: Contributor
timestamp: May 08, 2013, 02:58:24 pm
content: Thanks.I get the same MD5 checksum but it does not work!I would prefer a PDF anyway. That is what the otherinstrument programming guides are.Pete.

author: Len
author_rank: Frequent Contributor
timestamp: May 08, 2013, 03:06:10 pm
content: Try this:Open the file's Properties dialog (right-click, Properties).If there's an Unblock button at the bottom of the Properties dialog, click it.

author: zener
author_rank: Contributor
timestamp: May 08, 2013, 05:37:26 pm
content: Thanks, that was it!I learn something every day.Pete.
Keithley 2015 Stray Voltage - Page 1
Forum section: electronics / testgear

author: sparknmike
author_rank: Newbie
timestamp: May 07, 2013, 09:20:21 pm
content: I just picked up a Keithley 2015 to add to my collection of useful junk. It was supposed to be working but it wasn't put through the paces to prove it works fine before I took it home. I am finding that so far it does seem to work but it does something odd that I haven't seen before. When there is nothing connected to the input the DCV reading slowly runs from zero to about -11.8V. If I set the scale to a lower range that doesn't over -11.8 it will eventually show an overload. If the inputs are connected to each other it does read out at zero.Is this normal for these meters? It seems like it is it just a floating input slowly building a charge. Since I have never seen a meter do this before it worries me a little that this is a minor fault and not an odd side effect of the high accuracy input circuitry.

author: don.r
author_rank: Frequent Contributor
timestamp: May 07, 2013, 10:39:03 pm
content: I think someone else here had the same problem with their 2015 or it could have been a 2000 and solved it by placing a high value (30Mohm?) resistor between the inputs. If I can track down the thread I'll post a link to it here.

author: ve7xen
author_rank: Super Contributor
timestamp: May 07, 2013, 11:09:14 pm
content: I don't have a Keithley 2015, but my bench meters do this on low ranges. With input impedance of 10gigohm, they quickly accumulate charge and have no path to bleed it off. I suspect the meter is probably working fine.If you put the meter on its 100V range (10megohm input impedance, per the datasheet), do the spurious readings still appear?

author: amspire
author_rank: Super Contributor
timestamp: May 07, 2013, 11:17:05 pm
content: Quote from: sparknmike on May 07, 2013, 09:20:21 pmSounds right to me. You are just used to meters with a 10MOhm input impedance. For the 20V DC and lower ranges, the input impedance of the Keithly is extremely high - you would have a lot of trouble trying to measure it. This means it can be used to measure the output precisely from sources such as resistive dividers without causing any significant error so it is a very good thing.

author: EEVblog
author_rank: Unknown
timestamp: May 08, 2013, 03:31:38 am
content: Quote from: sparknmike on May 07, 2013, 09:20:21 pmYes, completely normal for meters with Gohm level input impedance.

author: sparknmike
author_rank: Newbie
timestamp: May 08, 2013, 07:36:17 pm
content: Thanks!The 100V scale doesn't quite settle on zero. Scales above 100V zero out though. It looks like all is well.I didn't realize the input impedance was in the GOhm range. It wouldn't be hard to build up a charge with that much resistance. To have a little fun I blew across the input terminals and indeed the reading went down temporarily.
Constant Current Supply  /  Frequence Counter - Page 1
Forum section: electronics / testgear

author: Ronald1962
author_rank: Contributor
timestamp: May 07, 2013, 04:43:01 pm
content: Hi folks,I'm looking for a constant current supply ( 1 nA up to approx. 100 mA) and a frequence counter ( up to approx. 1,5 GHz).The Keithley current sources Dave is using, are at the moment not available. Newer instruments from Keithley areunbelievable expensive...Used frequency counters are rare to get. And if there is one e.g. in the USA, the shipping cost are much higher tah 100 US $.Can anybody please give me some advices?Tanks in advance!GreetsRonald / Germany

author: Balaur
author_rank: Unknown
timestamp: May 07, 2013, 05:03:36 pm
content: 1nA is a bit tough.You can look for older HP 61** sources (6177C - 500mA, 6181C - 250mA, 6186C - 100mA).In the past, I had seen a few on the local ad sites (France) going for some ~100 euros.

author: c4757p
author_rank: Super Contributor
timestamp: May 07, 2013, 05:09:12 pm
content: I'd split the CC supply into two: sub-10mA and 10mA-5A or so. The design techniques for those ranges are somewhat different and I suspect you'll find it a real pain in the ass to combine them.

author: KJDS
author_rank: Super Contributor
timestamp: May 07, 2013, 07:47:54 pm
content: I may have some frequency counters coming, but won't know until tomorrow evening, and won't know if they work for another couple of weeks.

author: sync
author_rank: Frequent Contributor
timestamp: May 07, 2013, 08:49:52 pm
content: You should look at ebay.Keithley 225:http://www.ebay.de/itm/161018745108Frequency counters:http://www.ebay.de/sch/i.html?_nkw=frequenzz%C3%A4hler
O! NO!!!! NOT ANOTHER DSO  Yep! but I do need advice - Page 1
Forum section: electronics / testgear

author: MrsR
author_rank: Regular Contributor
timestamp: May 06, 2013, 09:53:40 pm
content: I am replacing my unused 2000 Series RIGOL with a new 2000 Series Rigol.Now the questions and a bit of a rant1 why is the fastest time base so slow on the 72 and 100meg only 5ns my old 25MHz scope has the same time base. The ATTEN 100MHz is 2.5ns and it's a Heap of poop!2 There charging $300 for a bit of software plus of cause the trigger update.If it entailed a hardware add on OK! but all the hardware is there...... What a rip off.OK! HELP.the Analog times on both are fast enoughSo what do I do buy the 72MHz and add extra memoryorbuy the 100 meg Scope and save up to activate the extended memory plus Trigger etc.THANKS FOR READING THIS POSTRachael

author: marmad
author_rank: Super Contributor
timestamp: May 07, 2013, 05:14:34 pm
content: Hi RachaelQuote from: MrsR on May 06, 2013, 09:53:40 pmPerhaps because it was introduced as a competitor to the Agilent X-2000 series (which has the same horizontal scales for it's 70 / 100 / 200MHz models).QuoteYou're not even paying for a bit of software - the code is already in the firmware - you're just buying a key (basically a number)But compare Rigol's prices to, for example, Agilent's - and they aren't too terrible.QuoteWell, the DSO comes with a free 36 hour trial period of all the options (memory, triggers, etc) - and the current version of the firmware has a bug which lets you keep resetting the trial period - so, for now anyway, you don't really need to pay to activate anything
Heathkit IN-3117 decade resistance box question - Page 1
Forum section: electronics / testgear

author: skysurf76
author_rank: Regular Contributor
timestamp: May 07, 2013, 05:32:15 am
content: I just bought a Heathkit IN-3117 decade resistance box from ebay for $50 dollars, and visually it almost looks brand new. Everything works and is well within specs, however two of the knobs are really really stiff. One of them is so stiff it hurts my fingers to turn.My question is what I can do to alleviate this. I opened it up and it just has rotary dials on the inside with several resistors connected around the outside of each. I was thinking about squirting just a little WD-40 inside the tight ones but I wanted to ask here first before I did anything. I don't know if WD-40 will act as an insulator or if it will attract dirt etc.Also the two connection posts on top have just a hint of oxidation inside them. I was wondering if there were any household cleaners or liquids that would be good to use on them.

author: mikes
author_rank: Regular Contributor
timestamp: May 07, 2013, 09:47:28 am
content: WD-40 has no place in this. WD=water displacer. Use it if your old car's ignition gets wet. Don't use it as a lubricant, because it isn't one, and will gum up after it sits a while.Possibly a few drops of light machine oil (sewing machine or gun oil) would help. It's hard to know - metal shaft/metal bushing which has corroded? Plastic shaft which has swelled?Have you removed the knob(s)? On some style switches, it's possible for the knobs to rub if they're located wrong (too low).
Korea vs USA HP Power Supplies - Page 1
Forum section: electronics / testgear

author: TimNJ
author_rank: Super Contributor
timestamp: May 05, 2013, 11:23:26 pm
content: I'm looking at buying an old HP 6216 power supply from. A made in USA supply is around $100. A made in Korea supply is around $75. Perhaps this isn't the supply to get anyway, but...just wondering if any junkie knew of any differences in quality between the two places of manufacture.

author: TimNJ
author_rank: Super Contributor
timestamp: May 06, 2013, 11:50:35 pm
content: Well anyway, I bought a HP 6214A (circa 1970) for $30 shipped. 1-12V, 1-1.2A, I believe.Good enough for me. It's a real crusty looking thing by the eBay pictures. I'll definitely have a restoration thread when I get it. Should be fun.
About the Rigol DS4014 data store (into a file) - Page 1
Forum section: electronics / testgear

author: roli_bark
author_rank: Regular Contributor
timestamp: May 06, 2013, 07:44:44 am
content: Hi,I'm told [by a local 'Rigol' Tech Rep] that captured data storing into a file (either in Tabular format, or in CSV format) can ONLY be done using the rear USB port (Slave ?).However, can captured DATA (not only Screenshot JPGs) be also stored using the front USB (Master ?) into either a USB DOK or a PC ?Thanks & nice forum!

author: commongrounder
author_rank: Frequent Contributor
timestamp: May 06, 2013, 03:31:31 pm
content: The DS4000 series scopes have three USB ports, two "host" ports and one "device" port. Either host port (one on front and one on back panel) can be used to store any of the waveform and/or setup data on flash drives. They show up as drive letters in the save menu. The device port is used to interface with a computer, or to plug into a pictbridge compatible printer. The print button on the front panel will send the print command, or in the absence of a printer, a bmp image file of the screen to a USB flash drive. You can read in detail about all of this in the user guide for the DS4000 series on the Rigolna.com web site:http://www.rigolna.com/products/digital-oscilloscopes/ds4000

author: roli_bark
author_rank: Regular Contributor
timestamp: May 06, 2013, 03:43:51 pm
content: Thanks for the info.But my question regards more sampled data storage [rather than screen bitmaps]

author: commongrounder
author_rank: Frequent Contributor
timestamp: May 06, 2013, 04:08:56 pm
content: I'm sorry I didn't state it clearly. Waveform data files (i.e. CSV) are included in the file types that can be saved on external USB flash drives, along with image and setup files. I own a DS4012 and have done this with no problems.The user guide has the specifics. Also, poster marmad has a slick custom program that gives access to the scope memory (through USB or TCP/IP) in more sophisticated ways. See "Software & Tips for Rigol DS2072 (DS02000 - DS4000 - DS6000 Ultravision DSOs).

author: roli_bark
author_rank: Regular Contributor
timestamp: May 06, 2013, 06:29:14 pm
content: Thanks !
How loud is your Agilent E3600 series power supply? - Page 1
Forum section: electronics / testgear

author: amahon
author_rank: Contributor
timestamp: May 05, 2013, 11:05:06 pm
content: I just unpacked and powered up a new E3647a and it has an unusually loud mains hum... akin to a cheap florescent light fixture (ie. with a poor ballast). That is with the outputs off. When under load it changes somewhat but not significantly. Definitely sounds like transformer noise / vibration. Otherwise, all else seems to be ok.It is many times louder than my Rigol DS2072 scope, my laptop, or anything else in my office for that matter. Is this normal?Thanks,Andrew

author: NickAmes
author_rank: Contributor
timestamp: May 05, 2013, 11:28:07 pm
content: I have an HP 6234A (a older model than the E3600 series, but of a similar design). It has a noticeable 60Hz hum when on. The noise doesn't seem to change under with load.
How to let out the magic smoke in a UT61E - Page 1
Forum section: electronics / testgear

author: Lightages
author_rank: Unknown
timestamp: May 04, 2013, 09:24:02 am
content: Some here might know that I fried my UT61E by trying to jam 2500 volts down its throat. It didn't like it and we are no longer friends. Well that's what you get when you push things to far.http://youtu.be/hhBbvIf3E0s

author: SeanB
author_rank: Super Contributor
timestamp: May 04, 2013, 10:01:13 am
content: Looks like i might just take a old set of phone line spark gaps and install them in mine......... I have plenty of them around, from dead fax machines that died from lightning hitting them. The spark gaps worked, but the power supplies never survive having the copper blown off them.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: May 04, 2013, 04:01:50 pm
content: I first thought why is there such a big difference between the setting and the measured value.Looked up your device and I saw that your device has an accuracy between 0 and +20% so +10% voltage is normal.Nice to see the brymen handles it correctly although I don't expect to measure any such high voltages.
Connectorless probes for oscilloscopes/logic analyzers - Page 1
Forum section: electronics / testgear

author: _sakiv
author_rank: Newbie
timestamp: May 03, 2013, 05:40:02 pm
content: HiI am using one of Xilinx's development boards (Spartan 3A) and it has multiple options for using Agilent connector less probes for debugging using a Logic Analyzer.I do not have a logic analyzer with me but I need to still debug the circuit. I have a Rigol DS1102E oscilloscope but the probes that come with the scope do not fit the bill here. The ground alligator clip is perfectly useless for this operation.Could anyone please advise the right action to take in this scenario ? I googled for cheap connectorless probes but couldn't find anything except for Agilent or Tektronix. The only option that I see is using single jumper wires in each hole but that is not good for sampling data as the wires are loose inside the tiny holes making for unreliable sampling.I appreciate the help.Regards_sakiv

author: MasterOfNone
author_rank: Regular Contributor
timestamp: May 03, 2013, 07:36:52 pm
content: I’m not sure what you are trying to do, but can’t you connect an FX2 Breadboard to the Development board and then change your design to also output the signals of interest on the FX2 edge connector. This way you could arrange multiple test points and add extra LED’s etc.

author: _sakiv
author_rank: Newbie
timestamp: May 04, 2013, 01:04:51 am
content: Sure I can do that for my current Spartan 3A board which has an FX2 connector. That does sound like a good idea to solve my current problem.However, I was still looking for a generic solution for connectionless probes if anyone had any suggestions.
amper clamp - Page 1
Forum section: electronics / testgear

author: hanndoddi
author_rank: Contributor
timestamp: May 02, 2013, 11:52:46 am
content: hey i am looking for a good amper clamp for the money Fluke is a bit to exspesive for me.I found this one what is your opinion and what are you useing?http://www.sealey.co.uk/PLPageBuilder.asp?id=22&gotonode=DoProductSearch&pageindex=1&method=mProductSearch&IndividualTypeID=1&category=6&productdescription=Clamp%20Meter%20NCVD&requiredresults=16&fulltext=1&analysiscode=

author: Psi
author_rank: Super Contributor
timestamp: May 02, 2013, 12:57:17 pm
content: That one cannot measure DC amps which may/maynot be a problem.
rigol ds2202 does not auto on i2c - Page 1
Forum section: electronics / testgear

author: Aido4ever
author_rank: Contributor
timestamp: May 01, 2013, 11:23:42 pm
content: Hi everyone.I got my new rigol ds2202 and i got 2 problems.1. the scope does not auto set when on i2c i only use manual setting.2. i got no decoding on i2c.another thing: i got no calibration certificate with the scope, and i got it with a dust on the screen. can i be it's not new?thank you all.
Hameg HM203-7 oscilloscope fault - Page 1
Forum section: electronics / testgear

author: d0pefish
author_rank: Newbie
timestamp: April 30, 2013, 11:39:24 pm
content: Hi thereI was lucky enough to be given an old Hameg HM203-7 oscilloscope by my college.It has a fault, so I'd love to try and repair it, I've always wanted a scope to help with my other projects.I'm not an expert when it comes to diagnostics and finding faults, so would really appreciate some pointers as to where to start looking. I am very competent when it comes to soldering though, so swapping parts out is no problem.The scope switches on fine, but to get the screen to show a flat line, I have to VERY carefully and slowly tune the Y-POS knob to a specific, tiny range, at which point the line quickly comes up from the the bottom of the screen.If I go much further than the mid-point on the Y-axis, the line quickly starts to get unstable and wobbles up and down. If I continue, the line flickers up and down the screen rapidly, and then disappears towards the middle of the Y-POS knob's range. If I keep going, the unstable line returns, and then there's another point towards the end of the knob's travel where the line is nearly stable, and finally it quickly moves off towards the top of the screen.This behaviour is identical on both channels. If I manage to get Channel 1 visible on the lower half of the screen, and then Channel 2 visible on the upper half of the screen, switching to DUAL mode shows both lines drifting towards and away from each other in a very unstable fashion.I have managed to locate a 203-7 service manual with some schematics here:HM203-7schSo far, I have done a quick test of the X-Y board's -12v, +5v, +12v and +152v which all look spot-on according to my multimeter.Does this look like a final stage Y-amplification problem based on the fact that it's happening on both channels?Secondly, I don't have any probes for this machine and am interested in buying some. I'm not very clued-up on oscilloscopes - but I assume I can't just use any old probe. Can anyone advise me as to what I should buy?Thanks in advance for any help-d
what is the difference between the HP3478A and the HP 34401A ?  - Page 1
Forum section: electronics / testgear

author: eevblogfan
author_rank: Frequent Contributor
timestamp: April 29, 2013, 06:49:51 pm
content: heyI bought the 3478A and I am very happy with it , at the work we had to measure the AC ripple of the E3610A under load , so I set up the whole setup and red 0.6XXmVRMS , and wrote the numbers ,in my home I tried that with my own E3610A and 3478A and the readings was 450uVRMS , BUT i've noticed that even when shorting the leads I get reading of 45XXuVRMS ! , and on the HP 34401A I got 0uV when leads shorted 0_0please tell me what's the deal wit that , thank you

author: robrenz
author_rank: Super Contributor
timestamp: April 29, 2013, 08:16:39 pm
content: this threaddiscusses very low level RMS shortcomings of even high end bench metersDownload the HP links onthispost. and read about proper ripple/spike measurement.This postalso shows a low level ripple measurement setup with a classic differential amplifier.
Damaged HP 6060B - Worth a punt? - Page 1
Forum section: electronics / testgear

author: Chet T16
author_rank: Frequent Contributor
timestamp: May 01, 2013, 04:09:59 pm
content: I see a damaged HP 6060B for sale near me, it says "needs repair or can be used for parts. The two transformers are broken off the unit."Pics:Its up for €100, is it worth taking a chance on? Seems like strange damage, dropped maybe?

author: Excavatoree
author_rank: Frequent Contributor
timestamp: May 01, 2013, 04:27:47 pm
content: With enough bodge wires, any PCB problems can be overcome. It's difficult to tell from the pictures if the transformer is repairable or not, that's the kicker. I'd imagine you'd have to get one from another parts unit, and then you may be better off fixing that one.I dug a clock radio out of the trash can at university about 22 years ago - someone must have thrown it. The transformer was ripped off the board and damaged. I was able to epoxy the transformer together and solder paper clips to the windings to make new leads. I can't believe I was able to repair it, but it worked for 20 years after that. I left it at my parents home and my mom got tired of looking at it (it was missing knobs, was badly scratched, etc) so she threw it away.

author: ddavidebor
author_rank: Super Contributor
timestamp: May 01, 2013, 04:29:42 pm
content: i'll bought it if i were you.

author: SeanB
author_rank: Super Contributor
timestamp: May 01, 2013, 04:31:10 pm
content: Dropped for sure, but easily fixable. Just going to need to remove the busted formers, make up a set of short leads to do the connections and bridge any broken traces. Offer a lower price, 60-80 Euro's will be worth the risk, possibly even the full price. Just check the display is not broken, and that otherwise it looks intact.

author: Chet T16
author_rank: Frequent Contributor
timestamp: May 01, 2013, 04:45:32 pm
content: A quick look at the service manual doesn't give any useful info on the transformers, i didn't consider they might be specific to it.I'll have to ask for more pics I think

author: krivx
author_rank: Frequent Contributor
timestamp: May 01, 2013, 04:58:14 pm
content: Just in case you've never bought anything on Adverts.ie, you can haggle. I would try a lowball offer.

author: Chet T16
author_rank: Frequent Contributor
timestamp: May 01, 2013, 05:34:11 pm
content: Quote from: krivx on May 01, 2013, 04:58:14 pmI have, its an annoyance really as sellers bump up asking prices as you always get offers for half the asking price. I still prefer it to donedeal though!

author: ddavidebor
author_rank: Super Contributor
timestamp: May 01, 2013, 06:25:27 pm
content: yeah, i know.i everytime buy things at half the original price O0
Insides of BK Precision 3831 - Page 1
Forum section: electronics / testgear

author: nadona
author_rank: Regular Contributor
timestamp: May 01, 2013, 04:18:40 am
content: I've been checking my new calibrator since it arrived yesterday. However I do not have many meters to measure with.This BK Precision is an item I have listed on eBay and already in the box, so I wasn't going to touch it, but out of curiosity I opened it back up to use it to measure.I ended up taking it apart and it is full of old discreet through-hole parts mixed with SMT parts and weird looking transformers.I'm posting this for your enjoyment.

author: wraper
author_rank: Unknown
timestamp: May 01, 2013, 05:07:04 am
content: That transformer is actually very good. It is called R-Corehttp://www.kitamura-kiden.co.jp/english/index.html. And it is better than toroidal. I don't see any weird through-hole and SMT combinations. There are through-hole electrolytic capacitors, nothing wrong with that. Some ferrite beads, optocouplers, voltage regulators, diode bridges and high power resistors. It is quiet normal that power parts are through-hole. And that big film cap just doesn't come as SMT.
Wavetek model 147 function generator manual / specs - Page 1
Forum section: electronics / testgear

author: lindworm
author_rank: Contributor
timestamp: April 28, 2013, 06:56:50 pm
content: Hey guys,I got a Wavetek model 147 at a fleamarket the other day, but it seems incredibly hard to find the exact specs or a manual online.For nearly all other Wavetek models the manuals are available on a bunch of sites but I could hardly find any more info than that it's a 10 MHz model.If any of you have more specs, tips on quirks or even a manual I'd be very happy ;-)Thanks for all the informative answers that I know will be coming in!Lindworm

author: jpb
author_rank: Super Contributor
timestamp: April 28, 2013, 07:05:36 pm
content: I see someone is flogging the manual on e-bay:http://www.ebay.com/itm/Wavetek-147-HF-Sweep-Generator-Instruction-Manual-Schematics-Rev-10-73-/390566461069but they want $45 for it which seems rather pricey!

author: grumpydoc
author_rank: Super Contributor
timestamp: April 28, 2013, 07:07:19 pm
content: QuoteIndeed - you could try making an offer.

author: lindworm
author_rank: Contributor
timestamp: April 28, 2013, 07:50:52 pm
content: Yeah I saw that but I don't really like the idea of supporting such vultures...that's why I was hoping someone here might have used one and knows all about it or maybe one of you works at a university where this is the latest fizz.Unis also seem to be hoarding manuals and such so maybe I'll get lucky.Thanks for your replies guys and have a nice evening!

author: ddavidebor
author_rank: Super Contributor
timestamp: April 28, 2013, 09:07:01 pm
content: send an email to wavetech, if they're still alive.just say"i'm repairing 8 of this great instrument!"work everytime

author: lindworm
author_rank: Contributor
timestamp: April 28, 2013, 09:52:35 pm
content: Yeah they've been bought up twice and now the function generator departement belongs to fluke.I'll definately contact them but I read that others didn't have much luck asking them for old Wavetek manualsEdit: after two months, someone finally uploaded the manual:http://www.ko4bb.com/Manuals/Wavetek/Wavetek%20Model%20147.pdfThese old instruments really are awesome, IF you can get a manual! The build quality is simply incredible and the manuals include full schematics, part lists and even calibration and repair tutorials.
Audio frequency range measurements, what hardware to choose ? - Page 1
Forum section: electronics / testgear

author: Mark Masterson
author_rank: Newbie
timestamp: April 28, 2013, 04:27:07 pm
content: .

author: commongrounder
author_rank: Frequent Contributor
timestamp: April 28, 2013, 04:47:06 pm
content: In my opinion, the main reason for the expense of these pieces of test equipment is to produce a useful measurement, the residual distortion and noise of the complete system must be at least an order of magnitude, or better, in specification, than any potential device under test. At least in theory, these days, 24-bit digital devices can reach very low noise and distortion residuals, but in practice, achieving those levels requires some very sophisticated analog circuit design. There are a couple of audio test units that are based on USB interfaces optimized for testing purposes, like the Quantasylum QA400 for around $200.00. But these are not an order of magnitude better than the best analog audio gear out there. If you want to check power output of amps at a certain distortion, then this kind of interface might work.I am not familiar with interfacing with Arduino and others. I'm sure other folks will chime in on this subject.

author: AndyC_772
author_rank: Super Contributor
timestamp: April 28, 2013, 05:46:01 pm
content: Quite right - a 24 bit ADC is a relatively inexpensive, off the shelf component. An analogue interface, power supply, clocking and data acquisition circuit capable of actually extracting 24 bit performance from such a device is a whole different ball game, and is an extremely high precision piece of equipment.As with all audio gear, you get what you pay for, and the law of diminishing returns applies. If all you want is a circuit that can tell you that an ordinary consumer grade stereo amplifier is working properly, then performance isn't that critical and you can throw together whatever combination of parts you like - but if you want to tell the difference between a $1000 amp and a $10000 amp, a piece of test equipment priced at the upper end of that range wouldn't seem unreasonable.

author: Lightages
author_rank: Unknown
timestamp: April 28, 2013, 05:50:48 pm
content: To what level of accuracy/noise/distortion do you want to measure? What bandwidth?You need to answer these questions first before you decide on the equipment. Depending on your answer you might be happy with a a good sound card and Visual Analyzer freeware.http://www.sillanumsoft.org/

author: olsenn
author_rank: Frequent Contributor
timestamp: April 28, 2013, 06:03:34 pm
content: Look at NwAvGuy's blog:http://nwavguy.blogspot.ca/
Review: Uni-T UT109 TRMS automotive multimeter with RPM and Dwell   - Page 1
Forum section: electronics / testgear

author: Spawn
author_rank: Frequent Contributor
timestamp: April 28, 2013, 05:12:39 am
content: A short review of Uni-T UT109 TRMS automotive multimeter and some information about cheap DIY stackable banana plugs.This is meter is not sold widely I think, for the cost of a UT61E you get less accurate multimeter but it has functions to measure RPM and Dwell degree which makes a good multimeter to use in a garage if you work old classic cars.This time I tried to shorten the review, so had to leave out couple tests, let me know what you think please.

author: Lightages
author_rank: Unknown
timestamp: April 28, 2013, 06:12:14 am
content: Good review and to the point. I think because it is an automotive meter that it should have been shown at least measuring the automotive functions, tach at least.You called the routed out parts of the boards "spark gaps" but that term is actually used for a component that has a specific breakdown voltage to add input protection. What you were referring to were the routed out sections of the circuit board to increase flash over protection should there be and overload condition. In any case it is rather ironic that the automotive meter seems to have much better input protection than the UT61E!

author: iloveelectronics
author_rank: Frequent Contributor
timestamp: April 28, 2013, 06:16:45 am
content: Thanks for the very nice review and the multiple mentions of me and my eBay store! I very much appreciate it!

author: Spawn
author_rank: Frequent Contributor
timestamp: April 28, 2013, 12:24:20 pm
content: Lightages, Thanks for the tips, some things just flip out of my mouth as English is my third language indeed I meant the gaps for ark jumping over at high voltages. You are right about in car measurement but it was night here and I can’t measure Dwell position in my car because it doesn’t have it and that is the most important part of the multimeter actually, I can’t seem to find time for my hobbies lately because of my work so I took the video at night.Franky, you deserve the kind words, I can’t mention enough how helpful you are upon my questions, thanks again
new high-end soldering station from atten - Page 1
Forum section: electronics / testgear

author: ddavidebor
author_rank: Super Contributor
timestamp: April 26, 2013, 09:15:07 pm
content: hi guys.surfing around, i've seen some very interesting atten product.150w cheap (induction heated?)http://www.attenelectronics.com/Products/Soldering_Tools/Soldering_stations/2012/0726/60.html...120-130€induction heated one (?)http://www.attenelectronics.com/Products/Soldering_Tools/Soldering_stations/2012/0702/8.html110€and new high-end soldering stationhttp://www.attenelectronics.com/Products/Soldering_Tools/Soldering_stations/2013/0402/246.htmlfor this one i can't find prices or sites to buy.the new look of the soldering iron in really interesting, standard atten one broke easy.

author: poorchava
author_rank: Super Contributor
timestamp: April 27, 2013, 02:32:41 pm
content: "Atten" and "high-end" are an oximoron.

author: ddavidebor
author_rank: Super Contributor
timestamp: April 27, 2013, 02:34:02 pm
content: high end of the wung lung crap.

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 27, 2013, 06:19:32 pm
content: @cwalex Has the Atten 315D, he doesn't seem to mind it, here is a link to him talking about it;https://www.eevblog.com/forum/chat/need-help-on-buying-a-starter-soldering-set-and-hot-air-station/15/@folic also mentions it;https://www.eevblog.com/forum/projects/soldering-station-controller-for-hakko-irons!/msg179535/#msg179535
Resistance and Capacitance Decade Boxes i bought off Ebay (pics) - Page 1
Forum section: electronics / testgear

author: sullyRD
author_rank: Contributor
timestamp: April 24, 2013, 05:12:45 pm
content: After winning a pair of Resistance and Capacitance Boxes off Ebay for £36 for the pair i had to wait for 12 days before they were delivered i found this strange because the seller had feedback off others saying "Fast Delivery" They finally arrived today in very bad packaging with no Bubble wrap . not good!!!After opening connecting up the box's in turn i found the Capacitance Box to be sound but upon connecting up the Resistance box i found errors in the readings.Two Blown resistors x10ohms easy to seeThe very top Resistor x100ohms has cracked in halfSame again x1.000 has blownThe x10 Dial from from aboveAs you can see its a easy enough fix once i remove the four blown Resistors, It is obvious from the condition of the Resistors that someone has applied a high power source to this Decade box but luckly it only took out four of the resistors.I have took readings from all the other resistors and they are all giving good consistent readings, These were advertised as "Good working order" which everyone can see they are most most definitely not.Can anyone suggest the best make of replacement Resistor with 5% tolerance closest to the the make of the resistors already in this Decade box? I do not know what make they are maybe someone else knows by looking the the photos. Many thanks if you can help.

author: SeanB
author_rank: Super Contributor
timestamp: April 25, 2013, 04:41:13 am
content: In the UK RS or Farnell have 0.5% resistors in stock, just buy as pack of 5 of both the 10R and 100R 0.4W metal film resistors there and put them in.
Fluke bargain of the century - Page 1
Forum section: electronics / testgear

author: RCMR
author_rank: Frequent Contributor
timestamp: April 26, 2013, 03:53:46 am
content: Don't miss this one folks:http://www.ebay.com/itm/True-NEW-FLUKE-15B-F15B-Digital-Multimeter-w-Free-Case-/320802917216?pt=LH_DefaultDomain_0&hash=item4ab1580b60Who could say no to that?391 folk have already said yes, apparently.

author: c4757p
author_rank: Super Contributor
timestamp: April 26, 2013, 04:02:59 am
content: They raise the price astronomically high when they're out of stock to avoid relisting fees, then just lower it again later.

author: iloveelectronics
author_rank: Frequent Contributor
timestamp: April 26, 2013, 04:49:27 am
content: Quote from: c4757p on April 26, 2013, 04:02:59 amSpeaking as an eBay seller the relisting fee is actually just a very minor concern. The selling history (the "XXX sold" part) is of much more significance as it definitely helps to give potential buyers a sense of confidence if an item has a healthy sale number. Having said that I don't personally do this sort of thing just to keep a listing active. I don't believe it actually conforms to eBay's policy. What I hate (well, maybe not "hate" but not very happy anyway) the most though is when a buyer buys all the remaining quantity I have on an item, hence ending the listing with all the sale history. I wish I had infinite monthly selling limits so this never happens (by entering very large quantity) but in reality I have to just monitor the remaining quantity of each item very carefully and closely and increase as needed. I also tend to enter some odd quantity number (like 11, 13 etc) so it's unlikely one buyer will buy all.

author: retiredcaps
author_rank: Super Contributor
timestamp: April 26, 2013, 05:28:23 am
content: Quote from: iloveelectronics on April 26, 2013, 04:49:27 amI can honestly say the sale history hasneverinfluenced my buy decision. I don't care if the seller has sold 1 or 1000 of the item. I care more about the % feedback and any negatives.
Supper Resistance decade box - Page 1
Forum section: electronics / testgear

author: mj21
author_rank: Regular Contributor
timestamp: April 25, 2013, 02:59:48 pm
content: got this four decade switches from boot sale today, i don't think the guy knew what they were.there was no box to them so i made one up. i think these are kinda the same as what Dave showed on the video.the switches and the contacts are all identical to Dave's one, and the resistors are wire wound. only down side is they go up to 11k per strip. at the moment i haven't connected them but if i connect them in series i should be able to get up to 33K. they are spot on.can some one please let me know, do i need to use special wire to connect the boxes together or that wont really mater?tnx

author: sullyRD
author_rank: Contributor
timestamp: April 25, 2013, 04:28:57 pm
content: Nice find mate, It looks like you got a good bargain there how much did you get them for?

author: mj21
author_rank: Regular Contributor
timestamp: April 25, 2013, 05:10:09 pm
content: lol, ya i was so happy. was watching daves video and was thinking be nice to own something like that, and how dave said don't ask about the price because we cant afford it. and few days later i found one. got them for £3 each.
4 exact same scope probes with different characteristics!  - Page 1
Forum section: electronics / testgear

author: AcousticBruce
author_rank: Contributor
timestamp: April 25, 2013, 04:40:57 am
content: I bought this 4 pack of 200Mhz probes on the Ebay. I hooked all for of them to the RF out on my HP RF sweeper. 1 to 110 Mhz sweep shows some interesting behavior.I realized that each probe had different characteristics. 1 prob at 50mhz would attenuate to a untriggerable wave form. Another at 70mhz.Watch this vid. Its just crazy!http://youtu.be/9v7SwegsLlcNote: All probes a calibrated on the same machine @ 10x mode.Questions: is this what you expect from brand new 200Mhz probes @ $58?Lol what do you guys think of this?Sent from my Note 2 using Tapatalk 2

author: amspire
author_rank: Super Contributor
timestamp: April 25, 2013, 05:18:40 am
content: I wonder if they are "repaired" probes where someone has replaced the original scope coax cable with conventional coax cable.Because the center wire in a scope coax is so fine, it can easily break after a lot of use or abuse.Using conventional coax cable will result in peaks and troughs in the frequency sweep. If you view a square wave, you would also get heaps of ringing on the edges.Is there anything printed on the cable?

author: rf-loop
author_rank: Super Contributor
timestamp: April 25, 2013, 06:09:53 am
content: Perhaps this picture tell more than thousand word.Fun.

author: amspire
author_rank: Super Contributor
timestamp: April 25, 2013, 06:23:42 am
content: Quote from: rf-loop on April 25, 2013, 06:09:53 amAre the ground lead loops enough to cause a big peak at about 20MHz followed by a big dip at about 30MHz? I suspect the probe connection is not the problem, but it is worth testing.The generator should have a 50 ohm termination, but it should perform OK without it.
How would I use a current shunt? - Page 1
Forum section: electronics / testgear

author: microbug
author_rank: Frequent Contributor
timestamp: April 24, 2013, 04:38:09 pm
content: Hi,I have got a pocket multimeter (Uni-T 120C) that can only do a max of 400ma current. I want to measure currents up to about 2 - 3A, and voltages with similar currents. Someone told me I should use a current shunt to do this, and that they aren't very expensive. A quick search on Ebay gives me a '10A 75mV Current Shunt Resistor', and there are many other similar things. I am a bit confused however, partly because I do not understand how these work and partly because it says 75mv - is this the max voltage it can handle?

author: Excavatoree
author_rank: Frequent Contributor
timestamp: April 24, 2013, 05:01:28 pm
content: I'll give it a shot - someone will no doubt correct me if I'm wrong.The current shunt is is series with your device under test, that is, the current you are measuring flows through the shunt. The shunt has a small resistance, so there will be a small voltage across it. You would measure that voltage with your voltmeter, as you would any other voltage.The shunt is specified as 10A, 75 mv. That means that when 10 amperes is passing through the shunt, you would measure 75mv on your meter. That is the max safe current. (I imagine this is to keep the temperature low enough that it won't affect the resistance significantly. There are probably other factors as well, but the important thing is the 10 Ampere limit)So, do the math to figure out what your current is based on the voltage that you measure. 7.5 mv would be 1 ampere, for example.This is how your meter works, there is an internal shunt, and your meter reads the voltage across it and does the math for you to display a current.

author: microbug
author_rank: Frequent Contributor
timestamp: April 24, 2013, 05:02:19 pm
content: Ah, ok - that makes more sense now!

author: mikes
author_rank: Regular Contributor
timestamp: April 24, 2013, 05:03:50 pm
content: A current shunt is simply a low value resistor, made to handle a lot of current. You put a current through it, and then measure the voltage across it, and use Ohm's law to figure out the current. A 10A/75mV shunt means it measures 75 mV when 10A are going through it. From Ohm's law, that means it's a .0075 Ohm resistor.

author: Wytnucls
author_rank: Super Contributor
timestamp: April 24, 2013, 10:29:32 pm
content: Even better, if you can spare the cash and don't go over 5A, get this panel meter with integrated shunt. Stick it in a box with a 9V battery and you'll have instant amp readings instead of playing with your calculator all the time.http://www.ebay.com/itm/DC-5A-Ammeter-Digital-Blue-LCD-Panel-Amp-Current-Meter-No-Need-Shunt-/190810222758?pt=LH_DefaultDomain_0&hash=item2c6d2cf0a6