Should I sell my 54645D for a new Rigol? - Page 1
Forum section: electronics / testgear

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 01:40:05 am
content: I currently own an HP 54645D Mixed-Signal Oscilloscope. It works fairly well, but it is big, heavy and lacking logic probes(the guy who sold me it no longer had them)I was considering selling it off for a new(or slightly used) rigol digital scope, like the DS1102E. The monitor looks easier to read and it is much lighter and smaller. Would that be a good idea for me? I mostly do simple digital stuff. I was thinking of keeping the HP scope IF I could figure out how to use the logic analyzer without HP's rare probes. Any suggestions?Thanks,Tom

author: VK5RC
author_rank: Unknown
timestamp: March 16, 2014, 01:56:44 am
content: I have a soft spot for Agilent gear, I would tend to stay with the HP and try to get a set of logic probes if it can then do what you need it to do.I bought one of the early Rigol digital scopes, but it dated very quickly, in 5 years I suspect the HP will still be going, repairable/serviceable and probably worth about the same, I am not so sure about the Rigol. I accept the Rigol will be sexier to start with.

author: EEVblog
author_rank: Unknown
timestamp: March 16, 2014, 02:02:37 am
content: No way I would swap that for a Rigol 1102E. Coincidentally, editing a video right now on the 54622D scope.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 02:17:41 am
content: Thanks for the quick response, you two. I'm going to experiment a bit with the Logic Analyzer port, and see if I could create my own pod for it. If not, I will put off some money to get a real one.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 02:41:14 am
content: Well, looks like I'd take more effort and money to find the right pod for my scope than to buy a separate analyzer. Maybe I can find a good used Agilent one to set down alongside my scope. Thanks again!(By the way, I look forward to that next video, Dave )

author: EEVblog
author_rank: Unknown
timestamp: March 16, 2014, 03:04:05 am
content: I've got a spare set of logic probes somewhere for these Agilent scopes, email me your postal address. I don't think they have any EZ-hooks though.

author: EEVblog
author_rank: Unknown
timestamp: March 16, 2014, 03:05:59 am
content: I was going to put my 54622A on ebay, but just realised in the video I encouraged people to put one on their ebay watch list, that kinda looks bad...

author: pickle9000
author_rank: Super Contributor
timestamp: March 16, 2014, 03:13:51 am
content: Awesome Murphy.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 03:14:06 am
content: Offer to sign it, that'll give viewers another reason to go out and buy yours!(I sent off that E-Mail, by the way)

author: echen1024
author_rank: Super Contributor
timestamp: March 16, 2014, 03:20:07 am
content: Quote from: EEVblog on March 16, 2014, 03:05:59 amPurchasing every 54622A on eBay now...

author: free_electron
author_rank: Super Contributor
timestamp: March 16, 2014, 04:03:25 am
content: i have tons of those hooks for the agilent copes. probably a few thousand.email address i'll send you a bunch for the scope.do NOt trade in the 645 for the rigol. the rigol can't compete with the 645 !the 645 was the first of the megazooms. it has 4 megapoints memory both on analog AND digital combined. the rigols don't have that.heck not a lot fo the current digital scopes have that !even though i have much faster and more powerful scopes than the 645 i keep two of them around ! quick mixed signal analog/digital debug ? grab a 645 !these machines frequently go for over 1000$ on ebay (when complete including the pods and probes), even though they are 20+ years old … People that have used them in the past swear by them.The 54622D is the successor. it adds a floppy drive and has an upgraded cpu. Agilent made the 622d becasue some of the original parts of the 645D went obsolete. functionally ( apart from the floppy and some protocol decoders) they are identical. they polished up the GUi and added some grayscale mode to it. and you can do firmware updates through the floppy on this machine. ( the 645d requires rom changes)

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 04:05:45 am
content: Wow, I must have been INCREDIBLY lucky. I won mine in an auction for $140 USD! It would have been a real winner if it came with the super-rare pods.

author: echen1024
author_rank: Super Contributor
timestamp: March 16, 2014, 04:08:34 am
content: @free_eCorrect me if I'm wrong, but I believe that the MegaZoom makes the scope feel much, much more responsive. After trying out the Agilent 2000X and the 3000X, the Tek TDS, DPO, and my Rigol all feel like cold molasses by comparison. I would believe that this is the magic of the on-die memory?

author: free_electron
author_rank: Super Contributor
timestamp: March 16, 2014, 04:13:27 am
content: the pods are not rare.part number 54620-61601they are the pods that were originally made for the 54620. that was a pure logic analyser ( like a 645 but without the analog inputs. ) the 620C even had a color lcd display ( 20 years ago !) and not those crappy 320x240 like in the rigol. this was a real 640x480 lcd !the pods are still in production today. if you buy a 5xxx 6xxx or 7xxx series scope they use those pods.the pods are active ! it is not just a passive thing.

author: EEVblog
author_rank: Unknown
timestamp: March 16, 2014, 04:27:53 am
content: Quote from: free_electron on March 16, 2014, 04:03:25 amThat used to be the case, but recently have gone for $350 or sohttp://www.ebay.com/itm/Agilent-54622D-Mixed-Signal-Oscilloscope-w-Accessories-/271394111647?pt=LH_DefaultDomain_0&hash=item3f3059809fEven a couple under $300.

author: free_electron
author_rank: Super Contributor
timestamp: March 16, 2014, 04:29:30 am
content: Quote from: echen1024 on March 16, 2014, 04:08:34 amthe megazoom is the key. the same technology sits in the 'big iron' infiniiums like the 54831 and 54832D ,Infinivision is the next generation of megazoom ( more on that in a second) the 2xxx 3xxx and 4xxx 5xxx 6xxx and 7xxx has thatMegazoom is , apart from the large memory, basically a huge resampling asic. depending on how you define the 'viewport' in the memory this asic resamples the data in storage and paints a new image.when you twiddle the timebase and offset knob on the frontpanel basically what you do is mess with two pointers : start and stop in the memory.the display only hs so many pixels ( 540 i believe horizontally on the 645d) ( there are more but those are for the menus and graticule , only 540 wide for the real trace data )the megazoom asic resamples the 'slot' you define in the memory and creates a new 540 pixel wide image. basically it divides your defined span in 540 slots and looks inside each slot and performas a peak detect. the result of the peak detect becomes the new pixel.that is why these machines dont show aliased images. that asic is incredibly fast. it can do this work withing1 refresh cycle of the old tv tube ( 60hz refresh cycle)you can see this process at work. simply touch your finger to a probe and look at the signal. tune it so you see about a period. look at how wide the 'trace' is. then hit the stp button. now see how small the trace has become. it is only 1 pixel thick !the 'wide' band you saw when the thing is running is due to the refresh speed. your eyes cannot follow the screen. combine it with the persistence of the phosphor in the tube . the megazoom asic can repaint a complete display inside the vertical blanking interval ! so it repaints the entire display 60 times a second.now, these older machines do have a blind time. they dont do 1000000 waveforms a second , but they can do a full sweep insinde the flyback of the tv tube. that is why they feel so incredibly fast. the megazoom asic can reprocess the entire image inside the blanking interval of the video signal that goes to the display.your 2xxx or 3000 feel 'sluggish' because it has to crunch a much larger pool of data , plus the lcd in those scopes does not refresh at 60hz. more at 30 hertz. so you have the impression of slugginess , in reality the machines crunch a much larger pool of data. they can't do that inside a screen refresh interval anymore..

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 04:30:02 am
content: Most auctions sell fairly low, since not that many engineers are prowling Ebay for bargains daily. However, the buy-it-now listings usually go for more.

author: free_electron
author_rank: Super Contributor
timestamp: March 16, 2014, 04:31:44 am
content: Quote from: EEVblog on March 16, 2014, 04:27:53 amonce in a while you get lucky. but if you want a calibrated one that is complete (probes, gpib or storage adapter). cough it up ! i know of companies that have automatic testsetups with these in em. and they pay big bucks to get complete , certified spares.the epxnsion adapters add storage memory , math functions and FFT on these machines.

author: EEVblog
author_rank: Unknown
timestamp: March 16, 2014, 04:33:09 am
content: Quote from: free_electron on March 16, 2014, 04:29:30 amThe 54622D has 1000 horizontal points, the "patented high resolution display, still beats many $20K scopes today. I'd like to find the patent on that BTW...

author: EEVblog
author_rank: Unknown
timestamp: March 16, 2014, 04:43:07 am
content: FYI:http://www.hit.bme.hu/~papay/edu/Lab/MegaZoom.pdf

author: echen1024
author_rank: Super Contributor
timestamp: March 16, 2014, 04:48:09 am
content: @free_eThank you for that detailed reply. Made my understanding about MegaZoom much clearer. my next scope will be Agilent. No more messing with this Chinese stuff. I had made that decision earlier, but this just reinforces my decision.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 16, 2014, 12:58:06 pm
content: Quote from: free_electron on March 16, 2014, 04:13:27 amThey are not active, but do have components inside - simple RC networks. You can improvise with ribbon cable & resistors if necessary.Cables & pods for the old JHP1650/51 logic analysers also work. You can sometimes find a set of 2 or 5 of these cheap with a free logic analyzer thrown in!

author: free_electron
author_rank: Super Contributor
timestamp: March 16, 2014, 01:55:34 pm
content: I eed to check this again, but i do believe there is circuitry in the box at the end of the cable. The pigtails are passive. But there are chips in the boxes. Maybe they are integrated passives.

author: oPossum
author_rank: Super Contributor
timestamp: March 16, 2014, 03:19:15 pm
content: Nothing in the box. A few passives in each probe cable.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 04:02:20 pm
content: oPossum, mind providing the value of those resistors?And I'm watching #591 right now. Same my 54645D doesn't come with custom saving...that means no rock game!

author: eurofox
author_rank: Unknown
timestamp: March 16, 2014, 04:19:52 pm
content: Quote from: free_electron on March 16, 2014, 04:13:27 amhttps://www.eevblog.com/forum/buysellwanted/agilent-54620-61601-probe/

author: oPossum
author_rank: Super Contributor
timestamp: March 16, 2014, 04:24:28 pm
content: 250 (or 249) ohm in series with 90.9 k ohm in parallel with 8.2 pF as described here:http://cp.literature.agilent.com/litweb/pdf/5968-4632E.pdf(page 9)Your 'scope has Bugs (Centipede). After the splash screen has disappeared and the trace grid has been displayed, press the [Print|Utility] key, then release. When the print menu is displayed, press and hold the second and third keys (from the left) directly below the CRT display, simultaneously. This will bring up the game.

author: Carrington
author_rank: Super Contributor
timestamp: March 16, 2014, 04:25:29 pm
content: I think it's something like this, I don't know the value of C2, but it is not necessary to know its value, is just curiosity.http://cp.literature.agilent.com/litweb/pdf/5962-8620E.pdf(page 3)Edit: New values.@oPossum: LOL ... that's synchronicity.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 04:55:35 pm
content: Thanks oPossum, that's awesome!As for the pods, I'm going to do some experimentation today, I'll try using hookup cable to directly wire to the 1.2KHz output and see what I get. According to an owner I have met on another site, the top row of the socket is mainly grounds while the bottom contains the signal pins.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 05:00:57 pm
content: I went ahead and put a hookup wire directly between the 1.2khz signal and one of the bottom pins, and as expected, I got a signal. Noisy and poorly trigged, but mainly because of my method of connecting it. I'm about to get some female-male jumpers for a more secure connection.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 05:12:49 pm
content: Alright, I got it hooked up. I'm guessing the reason that some other channels are picking up on it is due to lack of isolation, yes? I'm happy to see the analyzer working. Now I guess it is just a matter of designing and calibrating home-made probes should I decide to make some.

author: reagle
author_rank: Unknown
timestamp: March 16, 2014, 11:07:45 pm
content: I have 54645 in my lab as well, and as tempting as it is to get a DS2xxx Rigol instead, I can't yet justify that.My HP is probably 20+ years old and works fine, so chances are it will last even longer and I am yet to find a task it can't handle.Mine came from Ebay around 2008 for $300, thanks to some SRAM error message it kept showing. A quick NVRAM/battery swap and self calibration, and the unit was as good as new. This is still my only scope at homeThe logic pods/cables are a pain - they typically go for as much as the scope itself these days. I'd almost suggest getting Saelea Logic analyzer instead.With the 20% off codes floating around the forums, the 8 channel one is very inexpensive and knows how to decode all kinds of protocols.

author: Tohmas
author_rank: Contributor
timestamp: March 16, 2014, 11:22:09 pm
content: I was thinking of that too. I have a programming PC at my bench anyhow, so I could just plug that analyzer right in and likely use the software it comes with to greatly assist in interpretation of signals.

author: EEVblog
author_rank: Unknown
timestamp: March 17, 2014, 12:55:54 am
content: Quote from: Tohmas on March 16, 2014, 05:00:57 pmHang on, I'll ship you a genuine pod!

author: Tohmas
author_rank: Contributor
timestamp: March 17, 2014, 01:30:01 am
content: Alright, I'll wait up. Thanks!

author: free_electron
author_rank: Super Contributor
timestamp: March 17, 2014, 01:54:30 am
content: Quote from: Tohmas on March 17, 2014, 01:30:01 amsend me your info. ill send grabbers

author: hamster_nz
author_rank: Super Contributor
timestamp: March 17, 2014, 01:57:41 am
content: FWIW, I have recently got a Rigol 1102D if you want to ask any questions about it. Here's my inital impressionsThe one thing I wish it had was protocol decoding on the Logic Analyser functions.Having used it for a couple of weeks I wouldn't recommend the LA side of things over a Saleae Logic16 unless you want to do do true mixed signal work (e.g. trigger the LA from an Analoge domain signal). The LA triggers are a bit simple (H or L and a holdoff), and something with a more advanced mouse or touch interface would be far more useful when looking through large logic captures.With 8 active channels the LA seems to capture at about 2.5ns, so looks to be 'good enough' for up to 100MHz or maybe 200MHz at a stretch, but I haven't verified that other than by watching a few signals at max zoom and watch a few edges jump around.Also in a quiet room it sounds very noisy - like an old noisy PC noisy.Mike

author: Tohmas
author_rank: Contributor
timestamp: March 17, 2014, 02:34:00 am
content: Quote from: free_electron on March 17, 2014, 01:54:30 amThanks, I sent you an E-Mail yesterday, check your inbox/trash folder.

author: reagle
author_rank: Unknown
timestamp: March 17, 2014, 02:37:05 am
content: This is exactly what makes this forum so great

author: echen1024
author_rank: Super Contributor
timestamp: March 17, 2014, 02:39:20 am
content: Quote from: reagle on March 17, 2014, 02:37:05 amBrings a tear to the eyeGroup hug?

author: VK5RC
author_rank: Unknown
timestamp: March 17, 2014, 08:57:32 am
content: I have a sneaking suspicion its not the person, but the fear of some great piece of T&M equipment going down that brought out the cavalry!

author: Mark_O
author_rank: Frequent Contributor
timestamp: March 17, 2014, 12:23:37 pm
content: Quote from: hamster_nz on March 17, 2014, 01:57:41 amThat's true. But that's good enough to be able to trigger on packet starts. Which packet is another matter.But you've got a million samples with only 8 channels active, which helpsQuoteAlso correct. 400 MSa/s is the max rate of the LA.QuoteEh, not really. Remember that the BW of the scope is only 100 MHz. And the logic thresholds are going to be problematic anywhere near 50 MHz. I'd recommend it up to about 20 MHz clocks. Beyond that, you're on really thin ice.QuoteYes, that's an unfortunate characteristic, which I find annoying over the long term as well. I always feel a sense of relief when I shut mine off. OTOH, I've heard (and use) lots worse. I find a set of circumaural headphones and some decent music to be a good accessory for these scopes.

author: hamster_nz
author_rank: Super Contributor
timestamp: March 17, 2014, 05:42:38 pm
content: Quote from: Mark_O on March 17, 2014, 12:23:37 pmI didn't realize it until you pointed it out, but that is exactly my solution too!

author: EGDima
author_rank: Newbie
timestamp: April 22, 2014, 05:02:25 am
content: Rigol? Egh! You should either keep your 54645D or save up for a modern agilent!

author: EEVblog
author_rank: Unknown
timestamp: April 22, 2014, 05:06:10 am
content: BTW, did the probes arrive?

author: EGDima
author_rank: Newbie
timestamp: April 22, 2014, 05:29:27 pm
content: Speaking about logic pods/probes, they come with female connectors. What's the proper way to make male pin connectors? I know I can just stick 22 wire inside but that doesn't feel right.

author: Tohmas
author_rank: Contributor
timestamp: April 22, 2014, 08:49:49 pm
content: Quote from: EEVblog on April 22, 2014, 05:06:10 amAh yes, they have arrived and are working spectacularly! Many thanks, Dave!

author: Tohmas
author_rank: Contributor
timestamp: April 22, 2014, 08:51:40 pm
content: Quote from: EGDima on April 22, 2014, 05:29:27 pmAre you talking about the connector between the pod and scope, or between the pod and grabbers? Or the grabbers themselves?

author: EGDima
author_rank: Newbie
timestamp: April 23, 2014, 01:06:46 am
content: Quote from: Tohmas on April 22, 2014, 08:51:40 pmThe connector between pod and grabbers in case I don't use grabbers, but just want to plug the pod in the breadboard (the way it's possible with regular oscilloscope probes).

author: Tohmas
author_rank: Contributor
timestamp: April 23, 2014, 12:05:49 pm
content: Quote from: EGDima on April 23, 2014, 01:06:46 amAh, I'm guessing the pod has female jumpers that connect to the grabbers. You can try using a solid-core jumper wire. It shouldn't cause any problems in digital probing.When I probe breadboard circuits in hard-to-grab areas, I usually just put a scrap lead into the row and grab that.

author: David Hess
author_rank: Super Contributor
timestamp: April 24, 2014, 12:54:58 pm
content: Quote from: EEVblog on March 16, 2014, 04:33:09 amIt sure does. I was unaware of its high CRT horizontal resolution and may have to add this series to my list of old DSOs to watch for. In my mind, LCD based DSOs are only now catching up to this level of display performance. It is worth noting that a lot of old vector CRT DSOs has similar or better resolution in an even smaller screen size. Vector CRTs have an advantage in this respect since their horizontal resolution is limited by deflection and not z-axis modulation bandwidth.I did a cursory search for the patent but came up empty. I wonder if HP licensed the patent from someone else.

author: EGDima
author_rank: Newbie
timestamp: April 24, 2014, 10:05:53 pm
content: Quote from: David Hess on April 24, 2014, 12:54:58 pmBut it's not a vector CRT screen right? It's interesting that the resolution for the waveform are is 255x1000 points, I wonder what shape the pixel has then, vertical resolution doesn't seem to be that high, although the display has 4:3 standard aspect ratio.

author: David Hess
author_rank: Super Contributor
timestamp: April 24, 2014, 11:38:34 pm
content: Quote from: EGDima on April 24, 2014, 10:05:53 pmIt is a raster CRT so far as I know. The pixel spacing is obviously not square but that is hardly uncommon with a raster CRT.Some of the old DSOs which use vector CRTs are 1024 x 1024 on a 5x4 aspect ratio CRT which is only 5 inches diagonal so they predate the modern "retina" displays by decades. Most are 512x1024 or 256x1024 though.

author: edavid
author_rank: Super Contributor
timestamp: April 25, 2014, 02:31:19 am
content: Quote from: David Hess on April 24, 2014, 11:38:34 pmBut what is the spot size of those CRTs? I think real resolution in lines per inch is much less than the positioning resolution.

author: David Hess
author_rank: Super Contributor
timestamp: April 25, 2014, 03:04:24 am
content: Quote from: edavid on April 25, 2014, 02:31:19 amSince these vector CRTs were originally designed for high bandwidth analog oscilloscopes, they have a smaller than normal spot size by virtue of their high acceleration voltages but you are right, their positioning resolution is greater than their line resolution.I tested my lowest definition vector CRT which is 512x1024 and the spot size definitely yields better than 500 lines. I have some others (faster CRTs with higher acceleration voltages) which would do better.