Should I sell my 54645D for a new Rigol?

[Tohmas]

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

[VK5RC]

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.

[EEVblog]

No way I would swap that for a Rigol 1102E. Coincidentally, editing a video right now on the 54622D scope.

[Tohmas]

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.

[Tohmas]

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 )

[EEVblog]

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.

[EEVblog]

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... 

[pickle9000]

Awesome Murphy.

[Tohmas]

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)

[echen1024]

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... 

Purchasing every 54622A on eBay now...

[free_electron]

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)

[Tohmas]

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.

[echen1024]

@free_e

Correct 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?

[free_electron]

the pods are not rare.

part number 54620-61601

they 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.

[EEVblog]

these machines frequently go for over 1000$ on ebay (when complete including the pods and probes)

That used to be the case, but recently have gone for $350 or so
http://www.ebay.com/itm/Agilent-54622D-Mixed-Signal-Oscilloscope-w-Accessories-/271394111647?pt=LH_DefaultDomain_0&hash=item3f3059809f
Even a couple under $300.

[free_electron]

@free_e

Correct 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?

 the 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 that

Megazoom 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..

[Tohmas]

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.

[free_electron]

these machines frequently go for over 1000$ on ebay (when complete including the pods and probes)

That used to be the case, but recently have gone for $350 or so
http://www.ebay.com/itm/Agilent-54622D-Mixed-Signal-Oscilloscope-w-Accessories-/271394111647?pt=LH_DefaultDomain_0&hash=item3f3059809f
Even a couple under $300.

once 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.

[EEVblog]

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 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...

[EEVblog]

FYI:
http://www.hit.bme.hu/~papay/edu/Lab/MegaZoom.pdf

[echen1024]

@free_e

Thank 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.

[mikeselectricstuff]

the pods are active ! it is not just a passive thing.

They 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!

[free_electron]

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.

[oPossum]

Nothing in the box. A few passives in each probe cable.

[Tohmas]

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!