HP 54502 400mhz scope

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Tubetec

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I found one of these for sale , appears to pass all self tests , although there is an underlying issue with these models relating to the Dallas NV ram module .
Just wondering if anyone has experience of using these machines , the pluses and minuses , I really dont need anything fancy in a scope , maybe this unit is overkill .
How does a digitising scope differ from a modern digital unit ?
 

Tubetec

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Its advertised at 350 euros , but he might be willing to accept a lower amount . Trouble is if the NV ram backup battery is old it might not hold cal after powering down , even though it appears all is well in self test mode , it takes around 25 minutes to go through the 'cal' procedure each time you turn on the machine.

Ive seen a few of the Rigols go cheap on the secondhand market also DS1052z and DS1054z for 200 euros or even below that amount . The near instantaenous response of the old analog scopes might suit me better as I'll use REW for most measurement work in any case .
 

swpaskett

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This looks to be a mid-to-late-80s scope. I used a few from this series in some test rack builds oh-so-long ago. For the time they were slicker than snot, but I never met an HP scope that I liked for very long. My biggest complaint, and these are no exception, is that the trigger circuitry could never come close to Tektronix. I've had HP scopes miss transients that a Tek scope would reliably trigger on.
Compared to a modern scope in the same price range it is bigger, heavier, monochrome, probably more accurate if recently calibrated. I would consider both non-repairable. You might replace a fried resistor in the HP; other than that you are getting into exotic or obsolete parts.
Commodity digital scopes were pretty new back then and there was a lot of learning going on at both HP and Tek. HP was out-innovating Tek on the UI while Tek (IMHO) built better scopes and I loved -- still do -- all those knobs. The 54xxx series was meant to be a Tek killer and did on production lines, but as I said, they didn't get much love in the labs.
When I first started using these it was because we could connect them to a computer and do analysis that we used to do on paper and pencil, not to mention get rid of the scope camera which was a constant source of security violations for the techs (and me). We were able to knock down test time by over an hour per unit with these things and I got some relief from checking the tech's math in the test reports. The interface, if included, will be HPIB (IEEE-488) which will probably be useless to you unless you can pick up a card from NI, if they still make them, and if you do go down that road, do not expect a virtual interface to pop up in your browser. No SD slot or Bluetooth or USB.
If I am right as to its age, I think it's overpriced and you could do a lot better for the money with a new Rigol or an early-mid 00's Tek (24xx series scopes are good and in your price range). There's another thread somewhere dealing with them; models 2445 or 2465, if you want to hunt for it.
 

Tubetec

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Thanks Swpaskett,
Ive been keeping eyes open for a Tek 24xx series for ages ,
Theres a buddy of mine has one which he originally planed to get rid of( sell to me) , but I think once he got and used the modern Tek digital scope ,he's more inclined than ever to keep the old analog for all the good reasons you pointed out . Most of the math functions in modern scopes I wont need as Room EQ Wizard covers most all that functionality for me over and above the audio spectrum .
The HP54xxx is a great big power hungry lump and due to age could become problematic in the not too distant future . I did see a Tek 2430a for sale lately too , but thats digital ,
I can probably do without all the menus and settle for an old style switched analog front end .

I have a buddy who once worked for an electronics company here who produce armament control systems ,among other things . He was bound by non disclosure clauses of all kinds , but surprisingly they didnt stop him bringing the mobile phone into mil tech section back then . I saw a few sneaky photos of control panels and such like , looked a bit like 50's tube gear with bold jewel lens indicators, chunky toggle switches and heavy brushed stainless enclosures.
 

neil.johnson

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Aug 14, 2012
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54502: boat anchor. Pass along and get something more suitable for you.

That said, my 54622D is still a useful machine, although as others have pointed out unless you sort out a HPIB interface (or can put up with the sssllllooowwww serial interface) then forget about digital screen capture.

For your budget the Rigol is a good fit. Or look at second hand Teks. For most audio work, two channel 100MHz is a sweet spot. More channels can be useful, but watch that panel space. And get decent scope probes: x10 150MHz for a 100MHz scope.

Neil
 
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