hybridfree/eevblog-posts huggingface dataset:
current promo codes? - Page 1
Forum section: electronics / testgear

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: October 17, 2017, 03:59:26 pm
content: Does anyone out there have any current promo codes for major websites offering electronics testing gear such as Fluke 8845/6, Keysight 34461/5A, or any similar equipment?Much appreciated.

author: Pitrsek
author_rank: Regular Contributor
timestamp: October 17, 2017, 05:57:46 pm
content: Since the year is coming to end, you might want to ask your local distributor about clearance of demo units. Usually they don't want to keep demo units on books(taxe issue I guess?) and are selling them with a rather interesting discount.
BWD 820 oscilloscope questions - Page 1
Forum section: electronics / testgear

author: snapatap
author_rank: Newbie
timestamp: October 15, 2017, 01:27:56 am
content: I'm pretty new to electronics, I picked up a BWD 820 scope today for $30, i figured it was too cheap to pass up.I was following the first time operation steps in the manual, but the probe doesn't fit in the calibration socket. The probe is a Tektronix P6112. Is that the correct probe? Should I have a different probe?

author: tautech
author_rank: Super Contributor
timestamp: October 15, 2017, 01:51:35 am
content: Quote from: snapatap on October 15, 2017, 01:27:56 amWelcome to the forum.Does the probe have the grabber attached, you can pull it off.Do you have the hardcopy, here's the pdf version if you haven't got it.http://www.kevinchant.com/uploads/7/1/0/8/7108231/bwd_820_oscilloscope.pdf

author: snapatap
author_rank: Newbie
timestamp: October 16, 2017, 07:38:34 am
content: Thanks, thats the same manual as the hardcopy i got with the scope. I worked out that the probe has a removable grabber.
HP 8756A Scalar Analyzer? - Page 1
Forum section: electronics / testgear

author: Stray Electron
author_rank: Super Contributor
timestamp: October 12, 2017, 07:58:12 pm
content: I just picked up one of these and it appears to work. Does anyone have any words of wisdom regarding these? Does anyone have an of the HP11664A Detectors that you don't need? I'm limited to one at the moment.

author: ddrl46
author_rank: Regular Contributor
timestamp: October 15, 2017, 12:41:52 pm
content: Unlike the newer HP 8757A/B/C/D scalar network analyzer, the calibration data for the logarithmic amplifiers is stored in battery backed up RAM in the HP 8756A. If your instrument still has valid calibration data (it doesn't give an error during power up), it would probably be a good idea to check the batteries on the CPU board.You can do this via the front panel by pressing  ->  -> [A4 ADC] -> [CHAN VOLTS]. One of the values is labeled VBAT and is the battery voltage.If you do decide to replace the batteries I designed a simple CR2032 adapter to make it a bit easier to change the batteries in the future:https://oshpark.com/projects/ilkxtP1o, here is a picture of them installed on my HP 8756A its CPU board:If you ever lose the calibration data on one of these analyzers you need to recalibrate it using a rather expensive HP 11613B calibrator and some old HP BASIC program so it is best to prevent that from happening.As far as the detectors go, if you are unable to find any reasonably priced HP 11664A detectors, it is fairly easy to replicate the HP 11664C detector adapter and use your own RF detectors. The schematics for this detector adapter can be found in the HP 11664C service manual.

author: Bicurico
author_rank: Super Contributor
timestamp: October 15, 2017, 01:03:11 pm
content: Hi,Though I don't own such a device, I like to read about this stuff.Reading about the battery replacement before RAM loss, I wonder how to safely accomplish it, without losing the data in the process!Regards,Vitor

author: ddrl46
author_rank: Regular Contributor
timestamp: October 15, 2017, 02:04:44 pm
content: Quote from: Bicurico on October 15, 2017, 01:03:11 pmIt is actually quite easy in this case, this instrument has two batteries and you can safely remove one while the other one maintains the calibration data in the RAM. Just make sure you don't remove both of them at the same time and you should be fine.

author: Bicurico
author_rank: Super Contributor
timestamp: October 15, 2017, 02:55:03 pm
content: Thanks!My curiosity is satisfied!

author: Stray Electron
author_rank: Super Contributor
timestamp: October 16, 2017, 12:12:51 am
content: Thanks ddrl46. I was wondering about the batteries. It's not giving an error on boot up but I will check the Service menu. I should just go ahead and replace the batteries anyway.
Korad / Tenma power supply questions... - Page 1
Forum section: electronics / testgear

author: bd139
author_rank: Super Contributor
timestamp: October 14, 2017, 07:14:44 pm
content: Thinking about grabbing one of these, the basic 3A 30V single output units. I’ve got two other supplies but again, I ran out of outputs earlier and had to bodge something.Reading around there are two problem I have seen mentioned:1. Display failing.2. Accidentally triggering memory 5 and smoking the DUT.Can anyone comment on these issues and whether or not these are big problems or if they have been fixed?

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 14, 2017, 08:23:17 pm
content: Be sure to ask TopLoser about buying one. He might very well have what you want at a good price.Also, Dave sells them on Amazon, and has been for quite a while. That's a seal of approval in my book.

author: bd139
author_rank: Super Contributor
timestamp: October 14, 2017, 09:10:06 pm
content: That’s interesting with Dave. High praise there.Not too bothered about discount. CPC are selling them inc shipping for £59 inc VAT which is bugger all.
Lucked out on an Equipnet E4419B RF Power Meter - Page 1
Forum section: electronics / testgear

author: Tony_G
author_rank: Super Contributor
timestamp: October 14, 2017, 04:13:29 pm
content: I just got back from a business trip to New Jersey & London so I finally had the chance to unbox the RF power meter and sensor I bought from that enormous Equipnet auction so weeks ago.When I opened the wrapping on the E4419B I was a bit bummed out. I've been after one of these for some time but the prices they go for have been pretty damn high so I've always missed out. While it seems like I've been collecting RF power meters (I have a 435, 438 and a E4418), I really wanted to get the E4419B because it was a code compatible replacement for the 438A (runs the same GPIB instruction set) but it will read the calibration factors directly from the EEPROM on the power sensor.Anyway, I opened the bubble wrap and saw this:Bugger. Bad Ch B, bad main board, bad power board - I just bought either a parts mule or one seriously dead device.These units share a lot of parts with the E4418 so at least I was hopeful that maybe I could coble together a working unit so I thought I'd open it up to check it out. Inside it looked like nothing was swapped out so parts mule was ruled out, I didn't see anything blown up so I plugged it in and, lo and behold, it passed all the self tests. I gave it a quick once through and it seems to work fine.So I guess they just wanted to write it off and get something better.You can see the meter in this video:https://youtu.be/WulPCvJC7DwTonyG
Wallace and Tiernan FA129 Absolute Pressure gauge - Page 1
Forum section: electronics / testgear

author: crazyjim30
author_rank: Contributor
timestamp: October 14, 2017, 01:05:10 am
content: I realize that this isn't? strictly electrical, but I'm having some trouble finding an appropriate forum. I'm looking for the manual for this gauge. The current manufacturer, WIKA Instruments, has been unresponsive to my inquiries so far. If anyone can provide a copy of the manual or knows where I can find one, I would really appreciate it. Thanks.Sent from my Pixel XL using Tapatalk

author: babysitter
author_rank: Frequent Contributor
timestamp: October 14, 2017, 06:52:46 pm
content: Theirhttp://store.flw.com/products/wika-high-precision-absolute-pressure-gauge-series-1000-6a.htmllooks like it is the successor. Basically I would expect it to be a membrane manometer:The pressure port is separated from a evacuated chamber by a membrane. Applied pressure moves the membrane and the movement of the pressure is moving the needle, seehttps://en.wikipedia.org/wiki/Indicator_(distance_amplifying_instrument)Easy to damage by overpressure. The photo is so 1998 that I cannot read the scale, but if sensitivity is high enough you might see the needle moving with the pressure port open depending on atmospheric ppressure changing at your location. Just visit a airport for single-point-calibration, then. Great Device anyway, would love to have one.BRBabysitter

author: crazyjim30
author_rank: Contributor
timestamp: October 14, 2017, 08:32:36 pm
content: Thanks. You're right. It is, for a gauge, downright beautiful. The local calibration guy is coming to the lab next week, so I should know more then. I also bought a manual for a similar type gauge that I hope will be "close enough" for me to mount, plumb, and operate, the gauge.Sent from my Pixel XL using Tapatalk
Cmu-200 firmware - Page 1
Forum section: electronics / testgear

author: Kendhill57
author_rank: Newbie
timestamp: October 13, 2017, 02:30:13 pm
content: I've read most cmu-200 threads. ..can't find any dealing with getting firmware 5.21 ..the Cmu200 is discontinued product Amy ideas ...thanks for all the great posts on workings of the unitThanks

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: October 14, 2017, 04:09:26 pm
content: Here are some Firmwares:http://gotroot.ca/cmu200/There is also the Base5.21.
set of ds1486_ds1250_U1052_1055 wanted for TDS754D and TDS784D  - Page 1
Forum section: electronics / testgear

author: charlyd
author_rank: Frequent Contributor
timestamp: October 17, 2017, 08:15:08 pm
content: Hello i am looking for a complete imageset from both: - TDS754D (FW 7.X, one of latest, for 679-4349-00)and: - TDS784D (FW 7.X, one of latest, for 679-4349-00)i need a complete set ( from a working scope) Installed Options don t matter for me they can be set manually later.But if possible Fw 7.4E .Bin files from: ( Programmer exports )- DS1250Y Nvram. 512K -> Dallas ( location on CPU/DRam board)- DS1486 Timek. 128K -> Dallas ( location on CPU/DRam board)- U1052 stored Cals. 1K -> 24C02 (corner location on ACQ board)- U1055 stored Cals. 1K -> 24C02 (corner location on ACQ board)with such a set i am able to restore a complete scope in calibrated situation. ( of course from a different machine but )who can help me out
Tektronix FCA3000 - Page 1
Forum section: electronics / testgear

author: Robaroni
author_rank: Frequent Contributor
timestamp: October 13, 2017, 05:02:27 pm
content: Picked up an FCA3000 from Conres on eBay for a good price. Nice equipment, super clean, here's the link:http://www.ebay.com/itm/Tektronix-FCA3000-Timer-Counter-Analyzer-300-MHz-2-Channel-Demo/371980599426?_trkparms=ao%3D1%26asc%3D20140212121249%26meid%3Dc7bc806d7c384c118d30c1e7ec5454e6%26pid%3D100102%26&_trksid=p3693.c100102.m2452
RCA Voltohmyst with unknown socket/plug - Page 1
Forum section: electronics / testgear

author: Ghinessey
author_rank: Newbie
timestamp: September 26, 2017, 10:00:21 pm
content: Can anyone tell me what the socket/plug is pictured below on the bottom row of connectors 2nd from the left? I have never seen a Voltohmyst with this configuration. It appears similar to a Model 198

author: ataradov
author_rank: Super Contributor
timestamp: September 26, 2017, 10:17:51 pm
content: Can it be just a standard 1/4" audio jack?

author: Ghinessey
author_rank: Newbie
timestamp: September 26, 2017, 10:26:10 pm
content: it appears to be a 4 prong socket of some sort

author: ataradov
author_rank: Super Contributor
timestamp: September 26, 2017, 10:27:28 pm
content: Quote from: Ghinessey on September 26, 2017, 10:26:10 pmOk, I misread the question. I was talking about "DC VOLTS" connector.That I have no idea.

author: smbaker
author_rank: Regular Contributor
timestamp: September 26, 2017, 10:46:03 pm
content: It looks like a miniature version of a jones plug. I have a couple Voltohmyst WV-77E here, but neither has a socket like that.

author: Ghinessey
author_rank: Newbie
timestamp: September 26, 2017, 10:52:36 pm
content: Yes it does look like a cinch plug or jones I thought. But I was wondering what it was being used for.

author: Stray Electron
author_rank: Super Contributor
timestamp: October 12, 2017, 08:43:57 pm
content: It's called a "Jones plug" and they come in all different kinds of configurations and numbers of pins. Some of the old US military radios including the BC-348 (rear power connector) used them. I'm pretty sure that they were made by Cinch but I think other companies made them as well. You don't see them that much any more but the VoltOhmyst is an old meter.

author: TimFox
author_rank: Super Contributor
timestamp: October 13, 2017, 04:40:08 pm
content: The square "Jones" connector is not labeled on the front panel. Is it a socket added by a previous owner?

author: N2IXK
author_rank: Frequent Contributor
timestamp: October 13, 2017, 05:55:52 pm
content: Definitely looks like an "aftermarket" addition by a previous owner. If I had to guess as to function, I would go with filament and B+ output for some kind of amplified AC detector probe. Opening it up and tracing the connections would seem to be the way to go.As previously mentioned, the generic name for those type connectors is a "Jones plug". Still available from Cinch (formerly Cinch-Jones), through all the usual distributors.
Tektronix ISF file viewer - Page 1
Forum section: electronics / testgear

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: October 13, 2017, 04:17:12 am
content: Hi group,Some Tektronix scopes have the ability to save the raw acquisition data. The file format is called ISF.This is different than storing screen shots, if you load the ISF data back into the scope, you can scroll through the data like you had just acquired it.I am looking for an application that allows me to look at this data on a pc. I would like the same controls, zoom in, zoom out, pan etc.I can load the files back into the scope and do this, but I would prefer to do on a pc.I downloaded the Tektronix Open Choice Desktop. It doesn't see to have the controls needed.Another limitation is that you can only load one waveform at a time.The files I have are huge, 39MB for each trace captured with a 20 mega sample depth. I have a Tektronix MDO4104-3.Anybody know of anything?Thanks,Jay_Diddy_B

author: Alex Nikitin
author_rank: Super Contributor
timestamp: October 13, 2017, 07:59:47 am
content: I've looked at that problem a couple of weeks ago. There is a software package from Tektronix called TekScope Anywhere but it costs as a scope. You can open a file in OpenChoice Desktop and save it as a CSV, or you can actually save raw data from the scope as CSV and use Excel. It limits the length to 1M records though.CheersAlex

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: October 13, 2017, 12:55:07 pm
content: Quote from: Alex Nikitin on October 13, 2017, 07:59:47 amAlex and the group,I downloaded the Tekscope Anywhere software, I obtained the trial license. It looks like it has the desired functionality. I didn't see any limit, I was able to view my 20M records.Much better than OpenChoice.Thank you !Regards,Jay_Diddy_B
Advantest (ADCMT) 7351E DMM teardown - Page 1
Forum section: electronics / testgear

author: razberik
author_rank: Frequent Contributor
timestamp: October 10, 2017, 09:30:50 pm
content: Hello, after teardown of older, simpler Advantest R6441Ahere, I have another Japanese piece.ADCMT 7351E.There aren't many information about ADCMT equipment in English out there. But it seems these are very popular in Asia region, there are lot of them on Taobao and Yahoo jap. auctions.I bought this on ebay.I wasn't able to find out when this one was manufactured, but PCB silkscreen says 2006. It has USB connection and drivers for Windows are available. I will test it later.It doesn't have many functions and features. But this DMM looks great ! I love VFD displays.Mechanics is perfect. Assembly and disassembly is straightforward, no need of using force, compared to Agilent (like 34401A or 33120A).And these neat screws marked with red and green marker.I attach pictures.

author: razberik
author_rank: Frequent Contributor
timestamp: October 10, 2017, 09:32:43 pm
content: Internals. There are a lot of unused footprints, definitely forhigher models.

author: lukier
author_rank: Unknown
timestamp: October 10, 2017, 10:42:54 pm
content: What's the reference? I don't see the famous LM399.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: October 11, 2017, 08:43:56 am
content: LT1027 5V
Bluetooth DMM - Alternative to Their Crappy Software? - Page 1
Forum section: electronics / testgear

author: edpalmer42
author_rank: Super Contributor
timestamp: September 23, 2017, 11:07:09 pm
content: I picked up a cheap Bluetooth-equipped DMM. It's marketed by General Tools as Model TS04, but it's actually a Mastech MS8238D - it's actually silkscreened on the board.Unfortunately, the software doesn't work on my phone. General Tools just shrugged and said they only support major phone brands - mine is a cheap Chinese phone, but it is running Android 7.0. It has no trouble detecting and pairing with the DMM, but the app says it can't find the DMM. From what I've seen online, even if the app works, it's rather poor.I've never tried software hacking bluetooth, so I was wondering if someone could point me at some tools and info to help me dig into this and figure out what's going on and maybe cobble together something to pull data out of this DMMTIA,Ed

author: escape
author_rank: Contributor
timestamp: October 10, 2017, 09:42:56 pm
content: Sorry, no answer to your question, but I would like to bump this thread up and also ask for Android apps recommendations that can capture DMM data via BT.I just ordered another cheapie DMM (Southwire 16040T), and am looking for alternatives since the official Southwire app does not appear all that great.
Micsig sells their 150MHz 2CH touchscreen scope with $299 now? - Page 1
Forum section: electronics / testgear

author: jacklee
author_rank: Regular Contributor
timestamp: September 27, 2017, 09:57:36 am
content: I don't know if they have 150MHz with 4CH, I got it from theirAmazon store.Maybe they just set the wrong price, it's crazy, because which is even lower than 70MHz model.

author: Jim Kwik
author_rank: Newbie
timestamp: September 29, 2017, 10:01:47 am
content: I would like to buy Rigol DS1054Z which is quite famous for sure until I watched the Mike's video.Mike's videoTablet oscilloscope seems a bit fashion, I wonder if it is really that useful?I also watched thisOperation Introduction - Micsig Tablet Oscilloscope tBook mini SeriesWhich seems quite easy use, but I have no idea of if which has a good working performance. Maybe it's just looks good anyway.So if anyone had brought this scope? I'm still in the swing of mood for DS1054Z or give tablet scope a try.

author: Lancair
author_rank: Newbie
timestamp: October 04, 2017, 10:48:28 pm
content: QuoteA 4CH obviously not, at least not yet officially, only the 2CH TO1152. I asked Micsig last week about a possible "TO1154" in the near future, but got no answer on this topic. My other question, whether a 100MHz 4CH TO1104 can be upgraded to 150MHz later on, was answered with "TO1104 can not be updated to TO1154 - sorry". So let's see what happens. I somehow like this small tablet because of its portability and would possibly give it a try, if a 150MHz 4CH version is in the works and not too far away.

author: exe
author_rank: Unknown
timestamp: October 05, 2017, 05:54:55 am
content: Quote from: Jim Kwik on September 29, 2017, 10:01:47 amYes, seehttps://www.eevblog.com/forum/testgear/micsig-to1104-(similar-to-rigol-1104z)/andhttps://www.eevblog.com/forum/testgear/micsig-technical-support-join-in-eevblog/.BTW, google finds other references to this new scope. E.g.:https://www.telonic.co.uk/Micsig-TO1152-Plus-Tablet-Oscilloscope-p/to1152-plus.htm, also on aliexpress. So, the scope might be real.

author: nctnico
author_rank: Super Contributor
timestamp: October 05, 2017, 08:16:12 am
content: And the MicSig TO1104 review thread containing reviews by various people:https://www.eevblog.com/forum/testgear/micsig-to1104-(similar-to-rigol-1104z)/msg1089548/#msg1089548

author: TK
author_rank: Super Contributor
timestamp: October 05, 2017, 10:24:23 am
content: I contacted Micsig and It is real. It is the basic model without battery that is being sold for $299.

author: Jim Kwik
author_rank: Newbie
timestamp: October 11, 2017, 02:49:12 am
content: Quote from: nctnico on October 05, 2017, 08:16:12 amThank you very much, it helped a lot.
Teardown & Experiments with an Anritsu MS9710B 0.6-1.75um Optical Spectrum Anlzr - Page 1
Forum section: electronics / testgear

author: Hugoneus
author_rank: Frequent Contributor
timestamp: October 06, 2017, 02:42:47 pm
content: You can watch it here: [26 Minutes]youtu.be/dpCK6NXGqe0More videos at The Signal Path:www.TheSignalPath.com

author: TiN
author_rank: Super Contributor
timestamp: October 06, 2017, 04:32:04 pm
content: Top notch, as usual.

author: Dubbie
author_rank: Unknown
timestamp: October 07, 2017, 05:31:34 am
content: At first I thought “Not another spectrum analyser repair!” Then I saw it was optical. Nice! Very interesting.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: October 07, 2017, 07:32:20 pm
content: Quote from: Dubbie on October 07, 2017, 05:31:34 amWhat’s wrong with spectrum analyzer repairs? I thought people liked those.

author: Dubbie
author_rank: Unknown
timestamp: October 07, 2017, 07:36:20 pm
content: Nothing is wrong with them. I do like them. However there has been a lot and variation is the spice of life!

author: Hugoneus
author_rank: Frequent Contributor
timestamp: October 08, 2017, 04:59:35 am
content: Quote from: Dubbie on October 07, 2017, 07:36:20 pm

author: _Wim_
author_rank: Super Contributor
timestamp: October 08, 2017, 09:16:38 pm
content: To answer the question about the increased noise with the output attenuator turned on (if this is normal), mine (a MS9710C) does it also. However, my unit was pretty beaten up when I bought it, so it could just be a common fault from a weak part...

author: bjcuizon
author_rank: Frequent Contributor
timestamp: October 09, 2017, 12:25:27 am
content: Nice!What type of optical connector is that?..the one on the front panels of most of your optical instruments.

author: _Wim_
author_rank: Super Contributor
timestamp: October 09, 2017, 06:27:23 pm
content: Quote from: bjcuizon on October 09, 2017, 12:25:27 amThat would be the FC/PC-connector (non angled version). Sometimes it is also the FC/APC (angled version). The angled one are typically green (but not always).

author: Hugoneus
author_rank: Frequent Contributor
timestamp: October 09, 2017, 06:28:36 pm
content: Quote from: bjcuizon on October 09, 2017, 12:25:27 am_Wim_ provided the answer above. I also have a few videos about optics and I go through the details of these things.

author: bjcuizon
author_rank: Frequent Contributor
timestamp: October 09, 2017, 11:59:48 pm
content: Quote from: _Wim_ on October 09, 2017, 06:27:23 pmQuote from: Hugoneus on October 09, 2017, 06:28:36 pmThanks for clarifying that to me.
High quality oscilloscope probes? - Page 1
Forum section: electronics / testgear

author: Fusion916
author_rank: Regular Contributor
timestamp: October 09, 2017, 06:53:51 pm
content: Any recommendations on high quality oscilloscope probes (150MHz+ BW, 1x-10x)? Looking for something with a decent awg wires, good BNC connector, good probe tip that does not require pressing the connection to get a signal on the scope.

author: David Hess
author_rank: Super Contributor
timestamp: October 09, 2017, 08:51:06 pm
content: I like Texas probes for their low cost. They OEM them for other manufacturers like Keysight. I would provide an Ebay link but their search facilities are down.

author: transistor12
author_rank: Contributor
timestamp: October 09, 2017, 09:20:46 pm
content: Use Agilent prob(10:1) 10074C

author: tggzzz
author_rank: Super Contributor
timestamp: October 09, 2017, 09:22:26 pm
content: Quote from: Fusion916 on October 09, 2017, 06:53:51 pmSomething like this, perhaps:http://uk.farnell.com/tektronix/p6248/probe-oscilloscope/dp/4352610

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 09, 2017, 09:50:45 pm
content: Quote from: tggzzz on October 09, 2017, 09:22:26 pmClose.

author: bd139
author_rank: Super Contributor
timestamp: October 09, 2017, 10:11:37 pm
content: Look around to see if you can find some Wittig W202 probes. Bought 10 packs of them of them a couple of years back but you'll have to kill me before I hand 'em over. Really nice quality, flat to 200MHz easily and cheap as the Chinese crap ones. They are OEM by Texas.

author: georges80
author_rank: Frequent Contributor
timestamp: October 09, 2017, 10:28:21 pm
content: http://probemaster.com/oscilloscope-probes/Decent quality, made in the US, free shipping within the US.cheers,george.

author: LaurentR
author_rank: Frequent Contributor
timestamp: October 09, 2017, 11:29:53 pm
content: Or Cal-Testhttp://www.caltestelectronics.com/ctitem/#!/20-probe-oscilloscope-passive-voltage/

author: Fusion916
author_rank: Regular Contributor
timestamp: October 10, 2017, 03:42:16 am
content: Quote from: georges80 on October 09, 2017, 10:28:21 pmAwesome, this is exactly what I was looking for. Thanks.
Buck converter input power  problem - Page 1
Forum section: electronics / testgear

author: transistor12
author_rank: Contributor
timestamp: October 09, 2017, 09:42:17 pm
content: I powered my dc buck module with a transformer .Transformer spec : input volt= 220v, Output volt= 24v , 190VA. I used bridge rectifier to make AC to DC and 1000 microfarad-50V capacitor to smooth . Now float voltage 35V.Buck spec : input = 5v - 32v. 5A model : XL4015After connecting the buck module burnt within 10 seconds.Before i used the buck with 12V 60A battery to power up the module and charged 18360 battery pack of my Bosch hand drill .I could not understand why transformer damaged the module. I guess :1) buck module can't tolerate ripple to the input side .2) Float volt may cause damage. Am I correct ?Any suggestion ? Waiting ......
UT-139c CAL mode - Page 1
Forum section: electronics / testgear

author: stj
author_rank: Super Contributor
timestamp: October 09, 2017, 12:59:11 pm
content: anybody know how to get into it??

author: cycleworks
author_rank: Newbie
timestamp: October 09, 2017, 01:13:09 pm
content: I've heard someone in here tell that must cal by eeprom.

author: Jacek_Paw
author_rank: Contributor
timestamp: October 09, 2017, 01:18:24 pm
content: Hi,AFAIR UT139 has DTM0660 onboard so check this post:https://www.eevblog.com/forum/testgear/cheap-aneng-meter-calibrationreset-procedure/msg1267492/#msg1267492

author: stj
author_rank: Super Contributor
timestamp: October 09, 2017, 02:39:21 pm
content: that post is wrong, and just speculation.i should have asked if anybody had actually put a 139c into calibration mode.
LeCroy 9450A Distorted Screen  - Page 1
Forum section: electronics / testgear

author: schenckb
author_rank: Newbie
timestamp: October 09, 2017, 04:39:20 am
content: Hi All,Long time reader, first time poster. I have a 9540A that I haven't used in some time (2 years). I remember when I last used it I had an intermittent problem where the display was totally distorted. Today after powering it on for the first time in a while, it's 100% distorted at first. After a little warm up, the grid appears fine but the menu and signal display are still bad. If I wait without trying to measure anything, it will start looking okay, until I try to change something.I've seen a few posts here and elsewhere about a bad display connection, but I've checked every wire on the display card. Before digging deeper, starting to look for a new display board, or God-willing, trying to debug a CRT, I'm wondering if anyone has seen this same issue?Pics, in order,Startup; After a few seconds; Grid Intensity zero; Intensity zero; After some time at steady state.Thanks!
Lecroy CATC- protocol analyzers software?  - Page 1
Forum section: electronics / testgear

author: EEngo
author_rank: Unknown
timestamp: October 07, 2017, 01:40:17 pm
content: Hi!could someone of the Lecroy CATC-Users confirm, that the licenses are stored in the hardware unit and they (should) run with the free software-download at lecroy?I am wondering if the ebay-units which usually come without software are any useful.Thanks,ingo.

author: gslick
author_rank: Frequent Contributor
timestamp: October 07, 2017, 08:44:29 pm
content: I only have experience with the CATC / LeCroy USB protocol analyzers up through the 2500H Tracer / Trainer model. USB protocol analysis is enabled on all analyzers up through those models with the free software download. Can't be sure about newer models.Traffic generation is a seperate license. Even if the unit has the traffic generation hardware it might not be enabled. Also on the 2500H Tracer / Trainer High-Speed is a separate license. I bought one on eBay which was Low-Speed / Full-Speed only and another which was Low / Full / High-Speed licensed. Not easy to be sure without running the software and checking the options licensed in the unit.

author: ollopa
author_rank: Regular Contributor
timestamp: October 08, 2017, 05:55:03 am
content: Yes they are useful. Even if you bought one new you're going to just download and install the latest software from their website. I have used the T3 advisor and own the older CATC full-speed analyzer, the USB Chief.The only caveat is that the USB Chief driver does not work on Win7. Sven (DXL on here) has a github with a driver he made that you can compile and sign yourself for Win7. I had some trouble compiling it but was eventually able to do it and it works fine.Done fear buying a used one as long as the hardware is known to be good.

author: EEngo
author_rank: Unknown
timestamp: October 08, 2017, 04:53:30 pm
content: Hi all,thanks, that sound's great. I already scored one of them
Cheap Power Supply Pitfalls - Page 1
Forum section: electronics / testgear

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 08, 2017, 03:20:31 pm
content: There are many like it, but this story is mine.My first "power supply" was the cheapest I could find, a little 0-40/0-40V boost-buck module that supported CC, CV, and could be easily powered from wall warts I had lying around. See attached image. They're still available for ~$15. Having been warned about cheap power supplies, I checked the turn-on and turn-off waveforms and found them quite satisfactory. Then I attached my DUT and after the second or third power cycle its microprocessor popped. It turns out that if you unplug this thing, regardless of whether or not output is enabled, it dumps its capacitors into the output -- 50W for a few milliseconds. Enough to fry my microprocessor. Bam.My next power supply had a brand name and has remained trustworthy to this very day

author: cepwin
author_rank: Unknown
timestamp: October 08, 2017, 03:24:34 pm
content: Thank you for posting this....it's not something I would have expected!
Anyone aware of a Fluke 174 ? - Page 1
Forum section: electronics / testgear

author: rkovvur
author_rank: Newbie
timestamp: October 05, 2017, 02:58:37 pm
content: Hi All:My local Frys store has a sale for a "Fluke 174" True RMS multimeter for $99 (with a promo code). That seems quite good for a fluke. Except that I cannot seem to find much info or reviews on this meter. Oddly, even the fluke website does not list the 174.The meter seems good and can measure capacitance and Frequency.I want to know if anyone else has this meter or is aware of it. I am trying to decide if I should save the $99 and get a Rigol oscilloscope instead.Thanks !

author: anishkgt
author_rank: Frequent Contributor
timestamp: October 05, 2017, 03:04:31 pm
content: Here is a review from amazonhttps://www.amazon.com/Fluke-Fluke-174-True-Rms-Multimeter/product-reviews/B01EX8MU66Www.Georgehobby.wordpress.comEquipments: DSO104z, Hakko FX888D

author: LaurentR
author_rank: Frequent Contributor
timestamp: October 05, 2017, 03:29:45 pm
content: There was a thread on this topic a couple of months ago since Fry's started pushing those (pretty much permanently now) down to $99:https://www.eevblog.com/forum/testgear/fluke-174/msg1230915/#msg1230915

author: beuford
author_rank: Contributor
timestamp: October 07, 2017, 08:59:48 am
content: I bought one from Frys - Nice little DMM (actual, kind of large...).Very accurate, low power (3 AA batteries), batteries and fuse accessible without disassembling the case (like on my old Fluke 77) screen backlight is really nice (black numbers on white screen when enabled; lookes like normal meter otherwise). Yellow portion of meter is part of case, not removable like on some other (more expensive) Fluke DMMs. Overall, very happy (and I paid $119, before they lowered the price to $99).Really can't be beat for the price. I also bought a Keysight U1233A on a lark (can't ever have enough gear) for the same price, but I like the larger Fluke 174 much better.Beuford

author: Dubbie
author_rank: Unknown
timestamp: October 07, 2017, 10:35:20 am
content: I have the 175 as a ‘round the house’ meter. I like it very much.

author: Tjj226_Angel
author_rank: Contributor
timestamp: October 08, 2017, 09:17:51 am
content: Just picked one up today from frys for 100 bucks.Seems decent. The autorange is pretty darn quick, and it seems accurate.The leads that come with it are kind of meh compared to other fluke stuff, but for 100 bucks I can't complain.The only thing that should be noted is that the max readable current is 400ma according to the specs. On the back of the meter it says that the max is 440ma and then something about 10,000amps? Not entirely sure what the deal is there.

author: Fungus
author_rank: Super Contributor
timestamp: October 08, 2017, 10:06:49 am
content: Quote from: Tjj226_Angel on October 08, 2017, 09:17:51 amThat'll be the fuse.
Fluke 8808A for bench DMM? - Page 1
Forum section: electronics / testgear

author: beuford
author_rank: Contributor
timestamp: October 08, 2017, 03:13:17 am
content: I am looking for a bench DMM. I'd rather buy new or factory refurbished than used. I have found a factory-refurbished Fluke 8808A for ~$600 US (with software and cable, i.e: the 8808A/SU model), which seems like a good price. Any other decent options to consider in the new/factory refurb arena at that price?Thanks in advance,Beuford
UNI-T UT81B/C for on tour audio diagnostics? - Page 1
Forum section: electronics / testgear

author: PeterKeuning
author_rank: Newbie
timestamp: October 09, 2017, 02:23:20 am
content: Hi,I'm a sound engineer/technician for a couple of bands here in The Netherlands.Every now and then the occasion arises to go on tour with one of the bands, and I will join them with my PA setup and we'll do some gigs with some offtime in between. All fine and dandy.Last august I went on a tour when after the 3rd (out of 12) gigs my speaker management unit stopped working on one channel. We did the remaning gigs using the set in mono on the remaining channel, so we managed, but it's not cool. Once I got home I immediately took out the unit and started poking around with a home made audio probe and found that one of the XLR connectors wasn't connected properly, the PCB traces were broken (underneath the connector, so very hard to spot visually).I wish I had a portable scope with my that moment in order to probe about and see where the audio path stopped. Now i've found the UNI-T UT81B (or C) both afforable and highly usable, as it's not only a scope but a digital multimeter as well (continuity and voltage are both things which are regularly checked while building/breaking PA setups). I absolutely don't care if it's off by 5 or even 10 volts and that the milliamp range isn't as precise as a Fluke, i just want a cheap meter which can do multiple things and doesn't cost me an arm and leg when dropped/run over/forgotten/stolen.Besides the story above; i've got 2 guitar amps (mosfet, non-tube/valve) which distort in a strange way on certain frequencies, that would be another thing to probe. Nothing terribly exciting, just a 1 KHz signal and probing around to see after which component it startes to distort.Alright, to make a long story short: Are both the UNI-T UT81B and C suitable for (analog) audio diagnostics? And if yes, is the 8 MHz difference in bandwidth between the B and C models worth the extra 40 euros?

author: Lightages
author_rank: Unknown
timestamp: October 09, 2017, 04:19:18 am
content: If all you want is a sanity check for signals, then the UT81B should be enough. If you want to do qualitative measurements on the signals then you need to look at something a bit more like a scope and less like a multimeter. I have not used this, but t looks more useful as a low bandwidth handheld scope:https://www.eevblog.com/forum/testgear/has-this-been-discussed-before-a-'decent'-portable-oscope-for-$70/msg1302870/#msg1302870and get a good multimeter to go with it like a BM257S.
Error in TDS520B schematics? - Page 1
Forum section: electronics / testgear

author: Jwalling
author_rank: Unknown
timestamp: October 07, 2017, 11:19:16 am
content: While working on a TDS540B, I noticed that the A/D converters have 100 leads. The 520B schematics (which are really for the 540B as they have four A/D converters) show that the lead count for the converters is supposed to be 160. This is the first time I've had a 540B on my bench since the schematics were leaked, so I've never had the opportunity to compare the them.Weird. Has anybody ever noticed this, or seen a 520B/540B with 160 leads on the converters?
Fluke 1953A - Page 1
Forum section: electronics / testgear

author: Zermalmer
author_rank: Regular Contributor
timestamp: August 23, 2017, 06:09:42 pm
content: Hi everybody,I bought from german ebay classifieds a FLUKE 1953A.The original photos doesn't shown the options and the overal view was bad on this pictures.So I wrote the seller a message and asked for bette pictures.After checking this new pictures I decided to buy this baby with the risc of treaten well on outside and bad on inside.The device is at least from 1977 (oldest sticker related to inventory in a company).Last time official calibrated 1989 by Philips/Munich (seals where unharmed)Last electrical safetytest 1994.How long it really worked in a company or at a small workbench at somones home or collected dust somewhere until now... I didn't know.(the seller inherited it with a old volcraft function generator and an old Hameg HM 207).In general I wanted an IEEEE Port, but have now to life with the option -02 BCD-outAnd as Time Base I got an option -10First touches after unpacking the package reveal.... fingers are sticking to the case.So I decided to break the seals and clean it at least outside.After removing top and bottom cover I cleaned them also from inside and removed a lot of dirt (not dust... you maybe know what I mean... can't explain it actually in english)For a 40 year old device with such an open expansion slot the inside of the 1953a where surprisingly clean and only a very very small layer of dust is detectable on the option 2 boardBecause of lag of devices at home for testing I decided to take it on work.As expected the first results at warming up where not really satisfying...but patience is a virtueOver the day the device measures a DCF77 timestandard with it's 10MHz output.At the end of the day the device running very stable with only a failure of 0,9 Hz +/-0,1HzSo the owners treatened the device very well and it is still in very good condition after the last calibration/adjustment 28 years ago.I have some more pictures... and if you are interested I will upload them, but I have to learn the restrictions of attachmentsBest regardsAndreas

author: Vgkid
author_rank: Super Contributor
timestamp: August 23, 2017, 07:27:43 pm
content: Nice I have a 1952a as a parts unit. Unfortunately someone blew the input matched fets. I really liked the displays Fluke used at the time in the 52/53 models.

author: Zermalmer
author_rank: Regular Contributor
timestamp: October 06, 2017, 07:50:20 pm
content: Hi,small update after a longer time of running 24/7 in a lab ( over 4 weeks now) and mostly measuring all the time the 10MHz of a DCF standard.The measuring of the 10 MHz settled down to 9.999.999,5 Hz with maximum jumps of +/- 0,2 Hz.. but it's more a +/- 0,1Hz.I am very satisfied with this device... now I have to arrange my workbench at home new to give this baby finally a new home for (hopefully) a long time.
probes? - Page 1
Forum section: electronics / testgear

author: lupinehorror
author_rank: Contributor
timestamp: October 08, 2017, 12:42:09 pm
content: all,picked this up. needs a good clean and a new mains plug but could anyone recommend some probes?cheers.col

author: Gyro
author_rank: Super Contributor
timestamp: October 08, 2017, 12:55:51 pm
content: I'm not sure how much you paid, but for a 10MHz scope you could do a lot worse than these:http://www.ebay.co.uk/itm/1-pair-of-60MHz-Oscilloscope-probes-leads-OWON-P2060-P6060-UK-seller-and-stock-/382231230291?var=&hash=item58fec1b753:m:maJUQU5Rv0wv-r-2Lgv_yFg

author: lupinehorror
author_rank: Contributor
timestamp: October 08, 2017, 01:24:43 pm
content: thanks for your time and reply.that particular item...'This seller has set buyer requirements for this item and will only sell to buyers who meet those requirements.'. very odd.in the right direction now. cheers.

author: Gyro
author_rank: Super Contributor
timestamp: October 08, 2017, 01:55:42 pm
content: No worries.Odd, presumably it's on number of feedbacks or something. Sometimes if you contact the seller with 'Ask a quesiton...' first, they are more accomodating. Worth a try.Similar items are available at similar prices on ebay from Hong Kong but oviously you have to wait.I wouldn't go above 60MHz probe frequency rating as the higher frequency ones tend to have a smaller range on scope input capacitance compensation (and of course are a bit more expensive).

author: lupinehorror
author_rank: Contributor
timestamp: October 08, 2017, 02:00:14 pm
content: been on ebay since 2004 and have a 100% rating (505 transactions it seems...) will have to go down the HK route. thanks for your help.

author: lupinehorror
author_rank: Contributor
timestamp: October 08, 2017, 04:45:13 pm
content: went with this...http://www.ebay.co.uk/itm/1Pcs-PP-80-Clip-Probe-Kit-60MHz-Digital-Oscilloscope-Clip-Test-Probe-Tool-GL/162674679519?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Mini Teardown: Tek 519 - Page 1
Forum section: electronics / testgear

author: khs
author_rank: Regular Contributor
timestamp: October 03, 2017, 04:24:45 pm
content: Hi all,here a mini-teardown of one of the fastest real-time oscilloscopes until about 1978.BW ist DC to 1 GHz, risetime is about 300 ps, fastest timebase is 2ns/cm and the sensitivity is about 10 V/cm.(http://w140.com/tekwiki/wiki/519)My copy comes from a nuclear research institute near Munich for 10 euros (including cables and adapters). Nuclear reseach requires fast realtime oscilloscopes, because the nuclear events are short and statistical.It was told me, about 1970 it was very difficult to get a time-slot for a measurement, so for the students the 519 of the institute was available for their work only from midnight until next morning.Unlike newer instruments this oscilloscope is very very robust. There is no amplifier, so there is more or less nothing to destroy.A sampling head can be destroyed within ns by a voltage of more than 5V. The internal 50 Ohm termination helps not much, because it is behind the sampling diodes, so before the pulse reaches the resistor the sampling diodes are blown.As a comparison, the 519 accepts pulses up to 100 V, so it is more or less not destroyable.Switching on requires some patience. During the power on delay all tubes reaches their operating temperature, then a relay switches on the HV power supply with a bang accompanied with a sizzle of the 24 KV acceleration voltage.So for 10 euros this bang for the bucks is unbeatable.The display is quite small, just about 2 cm x 6 cm, but the dot size is quite small, so it compensates it a little bit.A big advantage is the internal pulse generator. It generates a 10V signal with about 100 ps risetime with a reed relay and a delay line. It is adjusted by knobs for drive and frequency, so adjustment is made by listening.I think even in 2017 10 V in 100 ps is still hard to get for 10 euros.This instruments helped me to understand low pass filters. I was surprised to see every low pass filter is a band pass filter in reality. The time I buy it (long time ago), it was the cheapest way to get an 1 GHz oscilloscope.The comparison with the 7104/7A19 shows the relay pulse is not as clean as shown on the 519, but in most cases it's not essential (both pictures 2 ns/div).Please note in the T519-timebase picture the unsusual time/div switch position to get the switch as near as possible to the 4CX250F tube .The 519 and the 7104 are no scopes for the daily use. But sometimes it's helpful to have it.

author: rsjsouza
author_rank: Super Contributor
timestamp: October 03, 2017, 06:00:04 pm
content: Beautiful pictures! Thank you for sharing them and the story.I really wish I had more space - so many of these older oscilloscopes have been offered to me but I simply didn't have a decent place to put them... Oh well...
Advantest R6441A teardown - Page 1
Forum section: electronics / testgear

author: razberik
author_rank: Frequent Contributor
timestamp: October 03, 2017, 09:30:17 pm
content: If you ever wanted to know what's inside of Advantest R6441A.4.5 digit multimeter with bunch of functions. What a pity it has only 4.5 digits. It is pretty neat inside.I scored in on ebay, unfortunately seller didn't packed it properly, so rear bumper had to be repaired.Pictures attached.

author: razberik
author_rank: Frequent Contributor
timestamp: October 03, 2017, 09:33:27 pm
content: Internals:
HP 8341A Spare Parts or repair? - Page 1
Forum section: electronics / testgear

author: Mrt12
author_rank: Regular Contributor
timestamp: October 03, 2017, 05:27:14 pm
content: Hi,I got a HP 8341A with a bad YTO and faulty YO Driver A55.I know only these two assemblies are bad because these two parts were removed from the working unit to fix a 8340A.I wonder whether it is possible to fix the YO or to find replacement parts? Has anybody some experience with that device?Tobias HB9FSX