hybridfree/eevblog-posts huggingface dataset:
modding a linear supply for 20A current limit? - Page 1
Forum section: electronics / testgear

author: SArepairman
author_rank: Frequent Contributor
timestamp: April 03, 2015, 10:36:59 pm
content: I was thinkingPSU -> Relay -> thermal fuse -> manganin shunt -> outputThe manganin shunt would have a instrumentation amplifier connected to it, the output of the instrumentation amplifier would have a reasonable LC filter, there would be a comparator and VREF/turn pot that would shunt the current to ground through a low RSon mosfet and open a normally closed relay, the mosfet would act as a "protector" and the relay would make sure the mosfet does not burn up. There could also be a thermal fuse that runs by the mosfet to open circuit the thing, just incase the relay fails.Is this a good protection scheme for an old supply? This way I would not have to modify the feedback loop of the original supply. It seems unreasonable to attempt a constant current source @ 20A, and I am not quite sure how the supply I can buy at a bargin is built. It also seems like its safer then using a control loop, as it cannot really oscillate out of control.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 03, 2015, 11:29:53 pm
content: A relay isn't much faster than a fuse, and a fuse is only there to protect the wiring...What's the circuit actually capable of (peak current, energy)? How long can it sustain a short before it explodes?Don't forget the flip-flop, either. As described, relay opens = current goes to zero = ahah, it's safe to turn on again = f00f.Using a suitably sized MOSFET for the switching allows active current regulation and quick turnoff, but you needa suitable circuit to do it.Tim

author: SArepairman
author_rank: Frequent Contributor
timestamp: April 03, 2015, 11:43:53 pm
content: well the idea was that the mosfet is turned on by the comparator, and it shunts the circuit to ground (so full 20A goes through a low Ron mosfet), and at the same time, a relay to break the circuit is triggered.The fuse is connected to the mosfet thermally, incase the relay does not open the circuit, the mosfet will get hot and open circuit.The idea is that the mosfet only works for as long as the relay needs to open, so it should not need a heat sink I think.It seems more reliable to use a pass relay and a "grounding" mosfet then a pass mosfet. Oh yea, the comparator output would latch, and the mosfet/relay would be driven by slightly more beefy transistors then in a regular comparator. The relay is normally closed.This is just a mod to attach to the side of a old school CV 30lb power supply to make it a bit more safe/lab worthy.
Video - Extending useful frequency range of spectrum analyzer  - Page 1
Forum section: electronics / testgear

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: April 06, 2015, 08:32:22 am
content: Hi,I have made a video where I show how I was able to extend usable frequency range of my Spectrum Analyzer using an external mixer.Probably you want to skip some sections if you find it boring and then come back if you still need details. Enjoy.Bacause I did screen capture at 1080P this video is best watched in HD. I am not exactly sure if it was a right decision to do screen capture recording in 1080P because some people may have slow connection - please let me know. Sorry for slow mumbling in some parts - making videos is hardI hope it will improve in future.

author: necessaryevil
author_rank: Regular Contributor
timestamp: April 06, 2015, 08:36:57 am
content: Nice video! Any chance there is a similar trick for upconverting a signal? Some folks want to look at audio on their SA...
Modular Hook to Banana Plug Test Leads - Page 1
Forum section: electronics / testgear

author: tec5c
author_rank: Frequent Contributor
timestamp: April 02, 2015, 12:25:46 pm
content: Attached is a screen shot from one of 'TheSignalPath' videos where Shahriar reviewed some fairly new Rigol power supplies.I am trying to find what brand/model these leads are. I can find very similar ones, i.e. Fluke have a set but the banana plugs are shrouded (not sure if it's a clip on type shrouding, in the video you can hear a click sound as though Shahriar unclips something just before he plugs the cables in - around 3:20 in the video)There are also a few other similar cables but they all seem to have stackable banana plugs. This is not a big deal (I will go with this if I can't find the singular ones), but I thought I'd ask around first.Also, I am aware Shahriar is a member of the forums and I have sent him a PM, though I'm not sure how often he is online/checks his inbox.Thanks all.

author: rdl
author_rank: Super Contributor
timestamp: April 02, 2015, 03:30:45 pm
content: I use Pomona Grabbers. They come in several sizes, Mini, Micro, SMD, etc. But they do have stackable plugs, and they're not cheap.

author: tec5c
author_rank: Frequent Contributor
timestamp: April 02, 2015, 03:53:14 pm
content: Quote from: rdl on April 02, 2015, 03:30:45 pmAh yes, I am familiar with these.The screen capture I gave isn't the best quality so here is a picture of a similar product. Essentially this is what I am after, just without the shrouded banana plugs. Or if anyone knows if the Fluke ones of these have a clip on shroud so to speak?

author: cyr
author_rank: Frequent Contributor
timestamp: April 02, 2015, 05:22:18 pm
content: I have a bunch of similar cables from this ebay store, run by a forum member I believe.http://stores.ebay.com/99centHobbies/Test-Leads-and-Accessories-/_i.html?_fsub=4211729014http://www.ebay.com/itm/Silicone-Test-Leads-50cm-with-Sprung-Hooks-and-Banana-Plugs-1-Pair-Red-Black-/200979921195They are nice silicone cables with unshrouded non-stackable plugs, decent grabbers and reasonable price.

author: dadler
author_rank: Unknown
timestamp: April 02, 2015, 08:57:33 pm
content: I use these all the time and find them incredibly useful for reusing my various shrouded leads with unshrouded jacks:http://www.ebay.com/itm/200904597758?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AITI have the exact same mini grabbers too. They came in this set:http://www.amazon.com/gp/product/B003AHE96G/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1That kit also came with the awesome springy micro probes with pogo pins, banana to 0.1" header leads, banana-alligator clips, banana-spade clips, and more. My favorite Fluke lead set.
tektronix tds 5052 - Page 1
Forum section: electronics / testgear

author: boughdiri
author_rank: Newbie
timestamp: April 01, 2015, 11:47:46 am
content: HELLO everybodyCan someone help me please?I have an oscilloscope TDS 5052 I lost my emergency disk and my HDD is deadI have the two operating system restore 063-3509-04 CD's but i can't to rebuilt it. the system tells me ''this is not a tds 5052''.There is a solution for my problem.thank you for help
xx 1061 branded lcz meter - Page 1
Forum section: electronics / testgear

author: coromonadalix
author_rank: Super Contributor
timestamp: April 03, 2015, 07:02:00 pm
content: helloI have won on ebay an zentech 1061 lcz meter, it is sold under many brand ... i am trying to find an user manual for it, with no luck.I whant to know if i can calibrate my kelvin probes, i have a few milli ohms of impedance (0.9 ohms) i whant to remove from measurements if possible, and i suspect my probe to be slightly defective, the wires are beginning to crack on the shielding, damaged and pinched on a few placesSended a few Emails to the companies still no luck ?? has any one played with thoses meters ?thks guys

author: commongrounder
author_rank: Frequent Contributor
timestamp: April 03, 2015, 07:31:30 pm
content: Have you zeroed your test leads with the open and short cal buttons? That will remove the lead resistance, inductance and capacitance from your test results.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 04, 2015, 02:53:08 am
content: tried but i dont know how to do it properly, i see open and short on the display, but after that i dont know how to calibrate iti will try on ebay an seller who sell them, if he whant to ship me a copy of the user manual.
I2C/SPI Trigger/Analysis Software for Agilent USB Modular Products Range - Page 1
Forum section: electronics / testgear

author: newcoppiceman
author_rank: Newbie
timestamp: April 01, 2015, 12:06:19 pm
content: For the last six months I’ve been researching oscilloscopes - things have moved on massively since I bought my last one in 1986, and I’m finding that choosing one is more difficult than I’d anticipated!I’ve recently had bench instruments on loan from R&S/Hameg and Agilent/Keysight and I'm familiar with similar products from the likes of Tektronix and LeCroy.Before spending serious money, however, I’m going to see how I get on with a pre-owned Agilent U2702A 200MHz 2-channel USB modular oscilloscope which I’ve just bought (at a price attractive to someone who, being retired, unfortunately no longer has the luxury of a corporate budget).The Agilent USB Modular Products range comprises industry-standard modules which can be used either stand-alone via USB2, or plugged into a chassis which will hold up to six modules. The range includes data acquisition modules such as the U2353A (which I also plan to have a play with, to see how this differs from a 'scope).I’m interested in I2C/SPI serial triggering/decoding (for an upcoming embedded design project) and I was wondering whether software products were available which would work with the U2702A and/or U2353A modules to provide similar I2C/SPI features to those available (usually as options) on modern ‘scopes.In due course I may decide to buy a top-notch bench ‘scope (like the Agilent MSO-X 3054A I had on loan) but for now I’m on a learning curve and just wondered whether software was available to crunch the data acquired by the Agilent modules for I2C/SPI analysis and triggering.I’d be grateful for any advice – even if it’s to tell me than I’m barking up the wrong treeA PicoScope, or Total Phase's Beagle I2C/SPI analyser are possible purchases, but I figure the T+M sector must have come up with some software for use with the Agilent USB Modular Products range for I2C/SPI.Thanks folks.
Can't get my Rigol 1054z to trigger? - Page 1
Forum section: electronics / testgear

author: LektroiD
author_rank: Frequent Contributor
timestamp: April 01, 2015, 10:02:07 am
content: I posted before about having trigger issues, I can't find the original thread now, but I still can't seem to get it to trigger. I've attached the 4 probes to the calibration posts, and this is what I get. I have tried loads of different trigger options, with different settings, but I cannot get the waveforms to lock into place.I am new to DSOs, and my analogue scope would lock straight on from any channel without a problem, but this thing is jumping around all over the place, it's unusable like this.Is this somthing I've missed, or is the scope duff?

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: April 01, 2015, 10:03:58 am
content: Perhaps increase the trigger level?As far as I can see, you're triggering on CH1, but the level is at the low level of the square wave.

author: tautech
author_rank: Super Contributor
timestamp: April 01, 2015, 10:07:56 am
content: Quote from: JohnnyBerg on April 01, 2015, 10:03:58 am+1Look at the Trigger setting at top right, it shows yellow (CH1) and zero volts.Raise the level.

author: electr_peter
author_rank: Unknown
timestamp: April 01, 2015, 10:42:32 am
content: Trigger is not set Edge type. Change trigger type.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: April 01, 2015, 12:22:43 pm
content: Use one probe connected to CH1, connect probe to probe test terminals, turn off CH2, 3 and 4. Press "AUTO".Does the scope display a steady waveform? It should, if not there may be a problem.As others mentioned, your triggering point is too low in the images shown.

author: Fungus
author_rank: Super Contributor
timestamp: April 01, 2015, 02:57:33 pm
content: Quote from: LektroiD on April 01, 2015, 10:02:07 amYour analogue scope probably triggered in AC mode, this one doesn't.Look at your image: You see the orange 'T' on the right hand side? That's the trigger level. You need to move it up a bit because right now it's in the 'noise' at the bottom of the signal.

author: aveekbh
author_rank: Regular Contributor
timestamp: April 01, 2015, 03:34:25 pm
content: Quote from: electr_peter on April 01, 2015, 10:42:32 amQuote from: Fungus on April 01, 2015, 02:57:33 pmSelect Edge Trigger (from the trigger menu, button under the trigger knob) and raise the trigger level. That's the most basic trigger, and it should work.
Fluke 87 - How much do you think I should pay - Page 1
Forum section: electronics / testgear

author: AusChris
author_rank: Newbie
timestamp: March 31, 2015, 02:10:55 am
content: Hey,I recently got myself a used Fluke 87 as a backup meter( I have 87-V model) and was pretty cheap for what it was, it was advertised as in "good condition" by the by seller. Clearly it wasn't, when I inspected it. Front Bezel is cracked, Screw holder is snapped, V/Ohms/Con jack seems to be cracked, but it works, but not as firm compare to the other jacks. But overall it functions pretty well for its age. (its from 80's btw. lol :9)Refer to imagesBut keep in mind, fluke does offer replacement parts, But they charge hefty price on shipping as I live in Australia. $30+50 shipping jacks, they stopped selling old fluke 87 front case, but I can easily repair it with some glue.Now for the accuracy, It seems pretty accurate in DC range, although when I tested the AC range on a 240v power outlet, I got a reading of 245v, so AC range must be out of whack. But I honestly don't use AC range that often, I can always rely on my 87-5 for those measurements. Besides that, it seems to be pretty accurate. I also ordered a DMM check from voltage standard and will see how off the measurements are. There's also a sticker, that it has been calibrated in 2009 for what its worth.Now to my main point. I made a dispute with the seller, he's willing to give me a partial refund. How much do you think is it worth? most of broken stuff doesn't seem to be ground breaking or affect its reading, it's more of a cosmetic thing. But If I wanted to repair it, I'm probably looking at $100 in replacement parts. So I'm thinking around $75? Or should I low ball him for $50? What's your opinion? Remember this is in AUD.

author: wraper
author_rank: Unknown
timestamp: March 31, 2015, 02:24:29 am
content: Quote from: AusChris on March 31, 2015, 02:10:55 amWhat, you test AC range accuracy against the mains voltage as the reference?

author: retiredcaps
author_rank: Super Contributor
timestamp: March 31, 2015, 04:22:26 am
content: If both your 87V and 87 read 245VAC while simultaneously measuring the same AC outlet/power bar, then there is obviously nothing wrong.You can try and repair the V/ohm input jack with some ideas from modemhead's blog.http://mrmodemhead.com/blog/fluke-banana-jack-repair/PS. Check to make sure both fuses are good. I buy used/abuse Flukes and approximately 50% of the fuses are blown despite the seller claiming everything works.

author: meeder
author_rank: Regular Contributor
timestamp: April 01, 2015, 09:01:31 am
content: Quote from: wraper on March 31, 2015, 02:24:29 amHere in the EU the standard is 230V +10%/-6% (216,2V to 253V) over a 24H period, so using the mains as a reference is not really practical
TDS 5000 series - Page 1
Forum section: electronics / testgear

author: boughdiri
author_rank: Newbie
timestamp: April 01, 2015, 11:44:12 am
content: HELLO everybodyCan someone help me please?I have an oscilloscope TDS 5052 I lost my emergency disk and my HDD is deadI have the two operating system restore 063-3509-04 CD's but i can't to rebuilt it. the system tells me ''this is not a tds 5052''.There is a solution for my problem.thank you for help
LCR meter vs (Blue) Q meter - Page 1
Forum section: electronics / testgear

author: staze
author_rank: Frequent Contributor
timestamp: March 31, 2015, 09:58:15 pm
content: All,Question. I have a DER-5000 LCR, which can measure the Q of inductors. I also see the painfully simple Blue Q Meter kit for sale from Anatek. I would assume my LCR meter could measure the same thing (though not with all the pretty LEDs), but I'm unsure what I would be looking for as "good" vs "bad" on something like a SMPS transformer, or say a high voltage transformer on a CCFL driver board from an LCD monitor.Any info? Or in this case, is the LCR meter not going to be able to measure what I'm after (testing these transformers)?
self-help book - Page 1
Forum section: electronics / testgear

author: artag
author_rank: Super Contributor
timestamp: March 31, 2015, 10:45:42 am
content: What on earth ?I'm guessing this is some sort of mailmerge bookwriter that inserts random topics into boilerplate. But perhaps it's a serious attempt to train the brains behind the next Tektronix ?https://store.kobobooks.com/en-GB/ebook/how-to-start-a-oscilloscope-business-beginners-guide?utm_source=uk.shopping.com&utm_medium=cpc&utm_campaign=title-How+to+Start+a+Oscilloscope+Business+%28Beginners+Guide%29

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 31, 2015, 10:53:53 am
content: http://www.zloadr.co.uk/publications/hm_ho.phpI feel sorry for humanity, really...

author: artag
author_rank: Super Contributor
timestamp: March 31, 2015, 11:06:33 am
content: I dunno. Keeping alive lost skills ?http://www.zloadr.co.uk/ebooks/book.php?id=37145

author: electr_peter
author_rank: Unknown
timestamp: March 31, 2015, 11:10:14 am
content: Quote from: PA0PBZ on March 31, 2015, 10:53:53 amCheck out the greatest hits of "How to start ___ business (Beginners Guide)" series. Each "book" contains the same text with different business name printed on it. Check out the contents of the book about oscilloscopes:books.google

author: TimFox
author_rank: Super Contributor
timestamp: March 31, 2015, 02:42:19 pm
content: If one wants to draft a document to which an arbitrary noun will be pasted, one should ensure first that the standard text does not contain sloppy mistakes such as "your" for "you're".
Agilent 2000x SPI Triggering - Bit Offset? - Page 1
Forum section: electronics / testgear

author: danielbriggs
author_rank: Regular Contributor
timestamp: March 31, 2015, 12:52:27 pm
content: Hi all,Does anyone know if it's possible to get an Agilent 2012 to "offset" its SPI decoding by one bit?I managed to do something to the same effect when using I2C, but need to use SPI for this project.The SPI "packet" is comprised of 17 bits: bit 1 determines read or write (1/0 respectively) and then the next byte is an address, the second and final byte is data byte.The scope is interpreting / decoding from byte 1 (correctly!), not byte 2, so everything in the lister is kind of bit shifted and the end of the first byte slips into the second etc.What I'd like it to do is starting decoding after byte 1, so I get, for example: 0x01, 0xDE, 0xAD for a read, and 0x00, 0xBE, 0xEF for a write.I poked around pushing buttons for a bit, but couldn't make it behave. It's not critical, but would be a time saver + helpful having the correct data in the lister, as opposed to garbage.Or is this not possible?Thanks in advance!Dan

author: MarkL
author_rank: Unknown
timestamp: March 31, 2015, 02:09:02 pm
content: How about setting the word size to 9 bits?Assuming MSB first, this will make the scope decode the first 9 bits as 3 hex digits with the first bit falling into the first hex digit, followed by the next 8 bits in the next two digits.Then the decoding for the final 8 bits in the address would be ended prematurely by CS going false. I guess it's going to depend how the scope decides to display an incomplete word if the bits in the hex digits will be aligned the way you want.You'd have to try it.

author: danielbriggs
author_rank: Regular Contributor
timestamp: March 31, 2015, 02:26:59 pm
content: Perfecto!Thanks so much; so simple.Case closed.
Might take a chance on this HP 5342A Microwave Frequency Counter - Page 1
Forum section: electronics / testgear

author: xrunner
author_rank: Super Contributor
timestamp: March 28, 2015, 11:44:53 pm
content: That display has just got all the bottom LED segments not working. I'm betting that isn't a hard problem to fix. That's not an issue with the LEDs, it like cabling or a connection thing going on. What do you think. I mean for $15 (if I win it).

author: grumpydoc
author_rank: Super Contributor
timestamp: March 29, 2015, 12:02:20 am
content: I'd say for fifteen bucks it's worth a gamble, looks like one driver is dead and the service manual is easily available (just google it).The one bit of caution I'd offer is that photo give you no information about whether the inputs work but if it's cheap enough, go for it.

author: VK5RC
author_rank: Unknown
timestamp: March 29, 2015, 12:11:24 am
content: If it is a simple problem it is a good price, I recently fixed my 5342A over the summer break but it took me quite a while to find the problem, some of the ICs are old but can be obtained if it not the main processor, there are good manuals available but if it is a software gremlin a "Signature analyser" is needed, these can be purchased but often go for a few hundred. Fault tracing can be a bit hard as the PCBs (about a dozen of them) are stacked very closely, in the service manual they use card extenders which are unobtanium. Spare PCB cards come up quite frequently. I ended up soldering quite a few wires onto the PCB to bring up the tested points while fired up. Also if you get it be careful to remove the feet before removing/opening the case as the feet hit the main PCB.Mine ended up being a stuck logic node , I used a saleae on the data lines going to the front panel. Below is a photo of mine pre fixing.

author: Vgkid
author_rank: Super Contributor
timestamp: March 29, 2015, 05:14:12 am
content: I would easily grab it for $15, I woud not even hesitate over that.

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 29, 2015, 10:28:58 am
content: I bought a dead one a long time ago. Happened to be a diode in the power supply. Those are always the easy ones.

author: xrunner
author_rank: Super Contributor
timestamp: March 29, 2015, 09:41:49 pm
content: I bid on it at $15 and somebody had a max bid set. I kicked the bid a few times more and I'm winning now at $20.50. Not sure how bad the other guy wants it. I'm not going to bid a whole lot more but we'll see how it goes.

author: dom0
author_rank: Super Contributor
timestamp: March 29, 2015, 09:47:49 pm
content: Why are you bidding on an item when the auction doesn't end in 1.17 seconds?

author: grumpydoc
author_rank: Super Contributor
timestamp: March 30, 2015, 07:11:05 am
content: Quote from: dom0 on March 29, 2015, 09:47:49 pm+1

author: edavid
author_rank: Super Contributor
timestamp: March 30, 2015, 05:16:58 pm
content: "Parts or not working" HP 5342As usually have a blown sampler, which is not repairable. Of course this one might be an exception, if it was put on the shelf because of the display problem.
DE-5000 LCR meter fixture connections (long). - Page 1
Forum section: electronics / testgear

author: TimFox
author_rank: Super Contributor
timestamp: March 29, 2015, 09:04:42 pm
content: I recently purchased a DE-5000 LCR meter and am happy with its performance at that price point.I want to build some specialized test fixtures, but have some questions about the 4-wire panel connectors.I shall sacrifice one or more TL-21 alligator-clip fixtures to connect with the three pair of blades on the DE-5000.Unfortunately, the operating manuals, including the good one from IET, do not give the details I want.Below, I assume that the circuitry inside the DE-5000 is equivalent to that in the G-R 1657, with one important exception.Start with Fig. 1 attached. This is a greatly simplified drawing of the General Radio 1657 Digibridge. The unit forces a current from I+ to I- and measures the voltage from P+ to P- with a differential amplifier Vamp. The internal resistor Rcurrent limits the current from the AC generator, and the second resistor Rsense measures the current flowing out of DUT into the virtual ground at I-, where the amplifier Iamp has a high output current capability to balance the generator current. The ratio of the voltage from P+ to P-, divided by the current through I-, determines the impedance of DUT.Fig. 2 is the G-R recommended circuit for measuring capacitors with a DC bias, supplied from an external battery (< 30 V).Since the 1657 only works with AC, there is a coupling capacitor Cc between the P+ terminal and the amplifier to allow this voltage. However, the DE-5000, which includes DC resistance, presumably resembles the circuit in Fig. 3 without the capacitor.In both units, the 4-wire connections are made with slots with two long blades: these blades contact each other with nothing inserted, but connect to opposite sides of an appropriate two-sided flat board inserted for external connections.Questions:A. Are my basic assumptions about the DE-5000 connections and function correct?B. If so, I assume that "-" and "+" for the DE-5000 (see Fig. 4) correspond to the polarities in the GR1657.C. However, it is not clear if the "x" and "y" blades in the slots (see Fig. 4, my nomenclature) correspond to "I" or "P". From the 1657 manual, I believe that the "P" terminals are closer to the display, and the "I" terminals are closer to the front edge on the Digibridge.From the top, according the photo of the main board in the 1657:P- P+I- I+D. Has anyone traced the circuit of the DE-5000 or found a good wiring diagram to verify these connections?E. I would only use the external Cc capacitor and bias supply for electrolytic capacitors. I may need to add a largish resistor from P+ to P- for proper DC on the V amp in the DE-5000.F. Do the two blades on the DE-5000 "Guard" slot connect separately, or to a common circuit ground? On the 1657, the external fixtures connect the fifth wire to the chassis ground through mounting screws.

author: omgfire
author_rank: Regular Contributor
timestamp: March 30, 2015, 07:30:46 am
content: C. Use multimeter to find AC voltage.F. Common.
Is this normal? HP3478A - Page 1
Forum section: electronics / testgear

author: Grecord
author_rank: Newbie
timestamp: March 31, 2015, 07:56:57 pm
content: I have an Ebay purchased HP3478A with intact cal stickers from 2007. It seemed fine, passes self test ok and has been powered on bench for last three months. I was measuring 1ma the other day and noticed LSD fluctuating 12-14 uA. I thought it might be in leads but it also fluctuates when shorted.I then checked Ohms with shorting bar and it also fluctuated 7-8 ct on LSD.I was planning to send to TresCal for recalibration but if it needs repair then I might reconsider.

author: KSP
author_rank: Regular Contributor
timestamp: March 31, 2015, 08:15:27 pm
content: Well due to the age of it i would say if its working then its probably as good as its gonna get.And as an ex Trescal employee I'll bite my tongue at that suggestionLets just say theres a reason why a lot of people have escaped their clutches

author: dom0
author_rank: Super Contributor
timestamp: March 31, 2015, 08:43:36 pm
content: Do the supply checks outlined in the manual. Service group A the first few paragraphs iirc.

author: Grecord
author_rank: Newbie
timestamp: March 31, 2015, 11:22:30 pm
content: Ok, thanks.

author: lowimpedance
author_rank: Super Contributor
timestamp: April 01, 2015, 12:03:14 am
content: Does it behave the same using the rear terminals ?.Perhaps the selector switch is a little dirty!.
H.P. to JEDEC numbers - Page 1
Forum section: electronics / testgear

author: George_Race
author_rank: Regular Contributor
timestamp: March 27, 2015, 08:39:39 pm
content: I am looking for replacements for 2 HP diodes.First: 0122-0105Second: 0122-0106Have been through all the H.P. JEDEC number charts I can find on line.Those two numbers are just not in any of the charts that I can find.Some help finding those two would be appreciated,George

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 28, 2015, 01:30:53 am
content: George,Can you post the schematic or details of the equipment that they are in?Regards,Jay_Diddy_B

author: George_Race
author_rank: Regular Contributor
timestamp: March 28, 2015, 02:29:59 pm
content: Hi Jay, the instrument is an HP-4271B.I am having trouble setting C and L screen readings to zero on startup.The trouble shooting procedures, in the manual, suggest changing diodes A10, A11 & A12.Attached is a screen shot of the parts as listed in the service manual, and the schematic of part of the A12 board.Thanks,George
tektronix 466 / Dm44 - Page 1
Forum section: electronics / testgear

author: siddhant9850
author_rank: Contributor
timestamp: March 31, 2015, 05:59:47 pm
content: Guys just got my hands on Tektronix 466 / dm44 oscilloscope. But I haven't got any idea bout which type of probe should be used for DM 44 please advice for the probes for Dm44. I am also planning to buy P6100 probes for the scope. Please advice me if I am going wrong anywhere. and please help me out with the probes for DM44I am also getting an error on DM44 will soon post the Image of it.

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 31, 2015, 06:19:16 pm
content: There's nothing special about the probes for the DM meters. Use any probes that you want.It's really not that great a dmm, but it is integrated nicely with the delay sweep measurment. Other than verifying that it works, I've never used the DM40 on my 465 to measure anything other than delay time. I do like the look of those scopes though.If you're talking about the temperature probe, you'll have to check the Tek documentation to see if it says anything. My manual says it's only good for +/-2 C.

author: siddhant9850
author_rank: Contributor
timestamp: April 01, 2015, 04:48:59 am
content: Thanks Paul but what about probe for oscilloscope..

author: PaulAm
author_rank: Frequent Contributor
timestamp: April 01, 2015, 07:34:58 pm
content: For the scope, the cheap Chinese ones work OK. If you look around a bit, you can find probes that have the resistor Ident pin and the correct scale light will illuminate behind the knob when you use the x10 probe.You can also find original Tek probes, but they're getting a bit old and it's getting a little chancy if the used ones are good.
How about Hantek8072E handheld oscilloscope? - Page 1
Forum section: electronics / testgear

author: beauty2003tt
author_rank: Contributor
timestamp: March 28, 2015, 08:49:26 am
content: Does anyone have using experience of Hantek8072E handheld oscilloscope now?I have bought one Hantek DSO5202P before and it works well.And I've heard from friends that they has a new handheld oscilloscope with generator function now.Has anybody already used it and could give me some feedback?Thanks a lot.
Tektronix 2432 CCD tear down - Page 1
Forum section: electronics / testgear

author: harrimansat
author_rank: Regular Contributor
timestamp: March 28, 2015, 09:51:22 am
content: Any body knows how to fix this thing? Before to ceramic break, of couse...

author: dom0
author_rank: Super Contributor
timestamp: March 28, 2015, 11:11:37 am
content: You could try soldering to the gold traces directly. I think Marc Michalzik did that a few years back on some very expensive RF assembly... so should be good enough

author: kony
author_rank: Regular Contributor
timestamp: March 28, 2015, 12:34:40 pm
content: I'd much more recommend conductive epoxy, if it won't have any negative effect on signals (higher connection resistance). Gold, especially in thin layer is very likely to get dissolved completely, if you are not fast enough while trying to solder it.

author: dom0
author_rank: Super Contributor
timestamp: March 28, 2015, 12:54:31 pm
content: Mr. Michalzik wrote that he was worried about that, too, but saw no such issues in multiple tries.Found the report he wrote about it (German):http://www.bymm.de/documents/13/Reparaturbericht_CMS_V1_9.pdf
King Craft MD10759 - Page 1
Forum section: electronics / testgear

author: meeder
author_rank: Regular Contributor
timestamp: March 26, 2015, 11:02:58 am
content: While I was looking to see if I could find my old "830" that the ALDI discounter sold years ago (don't even remember if it was Germany or the Netherlands) I did find another DMM that I bought at ALDI and I thought that it might be nice to take the thing apart. This one was sold by ALDI in Germany.It is the King Craft MD10759. No autoranging or any of that fancy stuff to be seen but ofcourse a transistor tester, where would one be without that...The front shows CAT II 1000 VDC/750 VAC MAX and 500 V MAX. There is no mention on the front that the fuses that are inside are only rated at 250V (and they are glass at that).The backside does reveal that the fuses are 250V. And the date is was sold is mentioned as well, 27th week of 2006.The inside reveals this. You can see the three fuses that are in the device, all three are 0,2A fast blow glass fuses rated at 250V.the front of the PCB. I did some tracing on the voltage input and the input goes directly to the selector tracks, so even if you are poking the probes at a 1000V it is happily transfered directly to the selector tracks.This thing is going directly to the wheely bin.

author: SeanB
author_rank: Super Contributor
timestamp: March 26, 2015, 07:12:20 pm
content: They even went to the trouble to make the 4070 quad Xor gate a COB unit as well, probably cut 2c off the cost of the unit not having to solder that little DIP package in.Why the 3 fuses though, did they think a fuse for the voltage and resistance ranges was going to be effective protection? Or is one of them on the battery connection.
ATTEN ADS1102CAL "FPGA not loaded" - Page 1
Forum section: electronics / testgear

author: ds18s20
author_rank: Newbie
timestamp: March 26, 2015, 05:18:33 am
content: Hello. I need help. My oscilloscope ATTEN ADS1102CAL was died some time ago. When I turn the power I see the message "FPGA NOT LOADED" on screen. What can I do with this?

author: pickle9000
author_rank: Super Contributor
timestamp: March 26, 2015, 05:29:33 am
content: That's a Siglent SDS1102CNL. You can try installing the Siglent firmware it will change your splash screen but otherwise the same.Of course if you have Atten firmware use that instead.
Need HP-4271 Extender Board - Page 1
Forum section: electronics / testgear

author: George_Race
author_rank: Regular Contributor
timestamp: March 26, 2015, 03:39:50 pm
content: I am working on an HP-4271B and need an extender board. Normally there is one plugged into spare slot 20, but you never see one in there!I would be willing to rent one if any of you have one available, will pay two way postage as well if needed.Is there anyone who builds HP extender boards? Seems that I read somewhere there was someone who did that, but can't seem to find any listing anywhere.Thanks,George

author: dom0
author_rank: Super Contributor
timestamp: March 26, 2015, 04:34:00 pm
content: http://stores.ebay.de/sparko6079If you can get your hands on a suitable slot connector (maybe ISA is a match? Those are cheap!) you can easily do them yourself, even without making a PCB (in that case some patience and a dremel is required).

author: George_Race
author_rank: Regular Contributor
timestamp: March 27, 2015, 11:19:25 am
content: I had considered making one, but got lucky last evening. Found an extender card in Europe for a reasonable price.So, my problem is solved, at least for the moment.Thanks to all who checked their junk boxes looking to help me!George
SDS1102CNL  vs  SDS1102CML (100Mhz) - Page 1
Forum section: electronics / testgear

author: 10101
author_rank: Contributor
timestamp: March 25, 2015, 04:03:46 pm
content: SDS1102CNL vs SDS1102CMLCould anyone say wich is the best and why please (if there is any relevant diference) ?Thanks in advance

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: March 25, 2015, 04:36:31 pm
content: I believe the CML has more memory, but still a pittance compared to the rigol 1054z

author: tautech
author_rank: Super Contributor
timestamp: March 25, 2015, 07:27:59 pm
content: Quote from: 10101 on March 25, 2015, 04:03:46 pmThe only relevant difference between these models is the memory depth, 40 Kpts vs 2Mpts.For other than detailed examination of a captured waveform it is unlikly you will see much difference.Both models have 1 Gsa/s sampling that is shared between both channels.The Siglent DSO range has an advantange over most compeditors with 400 V channel input ratings.This means more safety for your scope if the need arises to examine HV waveforms.Errors in usage also have a larger margin of error without damaging the scope.
New Tek DSO70000SX scope - Page 1
Forum section: electronics / testgear

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: March 24, 2015, 07:48:19 pm
content: Got an email today about this new Tek scope:http://info.tek.com/www-dpo70000sx-ati-performance-oscilloscope-wc.htmlInteresting form factor (well, different at least), 70 GHz bandwidth, etc etc. Well, can't comment any further, just thought it was interesting to post here.

author: Hydrawerk
author_rank: Super Contributor
timestamp: March 24, 2015, 08:24:42 pm
content: QuoteInteresting but LeCroy already has these specs.http://teledynelecroy.com/oscilloscope/oscilloscopeseries.aspx?mseries=484

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: March 24, 2015, 08:27:36 pm
content: Yeah... they do claim theirs is less noisy as well, but not quite sure. Did not compare specs of anything.Have no idea how much one of these would cost... a few hundred thousands I would guess?

author: gslick
author_rank: Frequent Contributor
timestamp: March 25, 2015, 03:04:01 am
content: Quote from: vinicius.jlantunes on March 24, 2015, 08:27:36 pmhttp://www.tek.com/oscilloscope/dpo70000sxDPO73304SX Analog Bandwidth 33 GHz Sample Rate 100 GS/s, 50 GS/s List Price $285,000DPO77002SX Analog Bandwidth 70 GHz Sample Rate 200 GS/s, 100 GS/s List Price $315,000

author: DJ
author_rank: Unknown
timestamp: March 25, 2015, 03:46:00 am
content: That's stripped.Nicely optioned, $285,000 - $479,000Only our governments can spend more money on a scope than most could spend on a house.
Current logging - Page 1
Forum section: electronics / testgear

author: Seyar
author_rank: Newbie
timestamp: March 24, 2015, 03:29:22 pm
content: Hallo it is my first post to this community. Therefore first I would like to thank everybody who share their knowledge to help others.I am second year student of electrical engineering and I love to help others but now I need your help.My problem is that I want to measure current of one circuit for one whole day. So I think that I need a current logger. I have fluk 45, normaal should I can logging the current with that device, like in this linkhttps://www.flickr.com/photos/linux-works/6836666508/in/photostream/But I can't, I have male usb/db9 so i just connect Rx of fluke to Tx of usb/db9 and Tx to Rx, GND to GND and once i tried DTR to pin 1 and 6 and other time with out DTR. I thought that it should work but I can't communicate with fluke (fluke RS-232 have just 4 pin. GMD,DTR,Tx and Rx). I tried servel software for it like (putty, hyper terminal and RS232 data logger) but none of them worked. So i contact the fluke for support but they gave me advice to buy their software, but for student it is very expensiveand i am sure that someone can solve this problem.So can you please gave me advice how to connect my fluke 45 to computer? Of is their any other way to logging the current of circuit for one whole day?I am doing this to find how much current does this circuit wil need for one day.Thank you

author: dacman
author_rank: Frequent Contributor
timestamp: March 24, 2015, 11:50:20 pm
content: Seems like it should have worked. Do you know if your USB to RS-232 adaptor works?If so, you need a null modem adaptor.For RS-232C DB-9:2-33-24-66-45-5Note: 7-8 and 8-7 are also wired on a null modem adapter. I'd ignore 1 and 9.(Note: I know that pin 6 isn't wired on the Fluke 45.)If I had a task like yours, I would set the Fluke 45 to print over the RS-232 bus, and capture the data with a terminal program.
BK Precision 8600 electronic load - any experience? - Page 1
Forum section: electronics / testgear

author: dadler
author_rank: Unknown
timestamp: March 24, 2015, 07:11:41 pm
content: Does anyone have one of these units:http://www.bkprecision.com/products/dc-electronic-loads/8600-150-w-programmable-dc-electronic-load.htmlThese newer models have USB/SCPI support and some other minor changes. Also, 3 year warranty.I searched and can't really find any info beyond the product page.

author: dadler
author_rank: Unknown
timestamp: March 24, 2015, 07:38:48 pm
content: I am aware that the other thread about the IT8512+ implies these units are related. I did not want to hijack that thread, and also wanted to know if the units are different. In particular, component selection, potential board differences like high voltage cutouts, positioning/type of the primary resistors, etc.In this thread:https://www.eevblog.com/forum/testgear/why-is-bk-precision-still-in-business-bk8500-programmable-load-oem-found/Dave mentions that BK precision provides value beyond just rebranding the cheaper products. The warranty may be part of it, but I wonder if there is other value/benefits? Dave said he would leave it up to BK to detail these benefits, which as far as I can tell, they never did.
Is a Fluke 8024A interesting? - Page 1
Forum section: electronics / testgear

author: apelly
author_rank: Unknown
timestamp: January 12, 2015, 10:08:26 am
content: I recently bought an 8024A on Trademe, because it came with an HV probe that I wanted. HV probes seem like hen's teeth on Trademe.Anyway, I'm wondering what to do with it. It seems to be in pretty good nick for its age, but I don't really have a use for it. I can either stick it in a drawer for occasional use or try and sell it.What do you guys think? Is it worth anything?

author: wiss
author_rank: Frequent Contributor
timestamp: January 12, 2015, 06:28:16 pm
content: Put it on a shelf as decoration?

author: retiredcaps
author_rank: Super Contributor
timestamp: January 12, 2015, 06:42:07 pm
content: Quote from: apelly on January 12, 2015, 10:08:26 amTake what you think is your multimeter that does fastest continuity and compare it to the continuity speed of the Fluke 8024A.Tell us your results.

author: apelly
author_rank: Unknown
timestamp: January 12, 2015, 10:44:01 pm
content: Quote from: wiss on January 12, 2015, 06:28:16 pmI like it! It just got upgraded from the drawer.Quote from: retiredcaps on January 12, 2015, 06:42:07 pmInteresting. I'll try this in a couple of days.

author: apelly
author_rank: Unknown
timestamp: April 01, 2015, 12:26:01 am
content: Quote from: wiss on January 12, 2015, 06:28:16 pmI'm slow, and I'd forgotten I promised this. I've just cleaned it up and was about to put it together, but I think I'll calibrate it first. That'll postpone this by another week or two.
DDS 3x25 Power-up Problem - Page 1
Forum section: electronics / testgear

author: alingerd
author_rank: Newbie
timestamp: March 23, 2015, 08:22:08 pm
content: Hello,I just got my hands on a Hantek DDS 3x25 arbitrary waveform generator. Unfortunately, I am seeing that when I plug the USB cable into the unit and it powers on, the AWG output swings to +3.5V for a short time, and briefly swings negative as well (to about -1.1V). You can see this in the attached image from a scope set up in persistence mode. Note that I am not using the auxiliary 5V DC input.Anyone else seen this issue and/or have a fix?Thanks!

author: dom0
author_rank: Super Contributor
timestamp: March 23, 2015, 08:28:56 pm
content: Power on/off glitching is far from being unheard of in function generators. So it's probably not faulty.Just by the way, I think you attached the wrong picture ; I can't see anything on it.Oh, now I get it.
Purchase choice, MSO or DSO + LA (Hantek or Rigol) - Page 1
Forum section: electronics / testgear

author: newtron
author_rank: Newbie
timestamp: March 23, 2015, 09:43:42 am
content: I have been for a while been playing with Raspberry Pi's and stuff but more recently I have been using the Pi for building analogue sensing projects or things that have quite a few analogue inputs. It is about time that I invested in an oscilloscope however I do not do this as a full time profession so can't really justify spending huge amounts on a scope. Though I will say, having a piece of rubbish is equally bad even for learning.I have basically narrowed a choice down to getting an MSO scope or a DSO + Logic Analyzer. Normally MSO scopes are a lot more however these are similarly priced which makes the decision a little weird and I wanted to see if existing users of the devices (if there are any here) have any views on them.The choices areHantek MSO5054F4ch, 1G/sa, 40Mhzalso has all the LA,AWG gubbinsTotal £300 to £330orRigol DS1054Z4ch, 1G/sa, 50Mhz+ Saleae Logic 4£263 + £85Total £348Understandably views of users are opinions and it may be sometimes project dependent but getting a 3rd degree on the topic from some users more professional than myself would be greatly appreciated.Thanks

author: EEVblog
author_rank: Unknown
timestamp: March 23, 2015, 11:34:39 am
content: The Rigol is a much better scope, you won't regret it.And the separate LA affords you some more versatility.

author: nctnico
author_rank: Super Contributor
timestamp: March 23, 2015, 01:17:01 pm
content: I would go for the MSO option if the MSO has decoding capabilities. A low cost logic analyser usually has very little memory or a low samplerate. You are likely to run into it's shortcoming sooner than you will with a decent MSO.I wouldn't buy Hantek right away though; first read/watch some review and investigate (unsolved) firmware issues!

author: dadler
author_rank: Unknown
timestamp: March 23, 2015, 04:27:17 pm
content: I would go with the 1054z + new Logic 8. I have both of these products and find they work great together. You can also send the Trigger Out on the 1054z to a digital input on the Logic, so that you can synchronize across the two devices if you wish.You will find a much larger userbase for the 1054z, and there is a reason for that. It seems like a loss-leader product, because of the features, build quality, and extreme hackability and for such an entry-level-priced scope.The new Logic products (well, Logic 8 and up) have higher sample rates and analog sampling. They are implemented as an FPGA+uC. There was a great Amp Hour episode with the Saleae guys, which covers the products and background on the company:http://www.theamphour.com/237-an-interview-with-joe-and-mark-garrison-subtly-spelling-sayleeay/While the Saleae products are not "high-end", they are certainly well designed and have great software. They are not toys. You have essentially unlimited memory, so you can sample for a long time and then just search the results for whatever data you wish. You can also write your own decoders/plugins if you can handle extending a C++ base class.
Rigol function generator repair  DG1022u- solved - Page 1
Forum section: electronics / testgear

author: shailesh3t
author_rank: Regular Contributor
timestamp: March 23, 2015, 08:29:39 am
content: Hi, just a short video for a repair of Rigol funtion generator DG 1022uthe function generator was not booting on , LCd remain idle , in fact a regulator was damagedregulator was replaced and testedhttps://youtu.be/xNGZudfwlMkregardsshailesh

author: Orange
author_rank: Frequent Contributor
timestamp: March 23, 2015, 10:10:59 pm
content: It looks like this regulator was already replaced earlier in your generator.Is this a weak point in the generator in general ?I have a DG1022, and had no problems yet with it. Is it perhaps overheating in your unit ?Anyhow nice video !Thanks

author: shailesh3t
author_rank: Regular Contributor
timestamp: March 24, 2015, 05:20:57 pm
content: i bought the generator second hand so maybe it was changed by the first owner but its a very nice generator very user friendly and i like the way its builtat first i thought it was the lcd that was damaged and was feeling very sad of loosing the generator