Oscilloscope

[Davor]

I'm about to acquire a Hitachi v212 scope. V222 was also offered, but someone else was faster. Hope it turns OK.

[Tepco]

Cheapest ticket to DSO world

And some tricks how to get it. Unavailable in some parts of the world, or at least not cheap.



Instrument on pic below is HP 54501 4 channel 100MHz scope, circa 1988-89 design, average Ebay price around 300$ or so for working one, but there is a catch, see another pic. Machine itself is typical “last forever” HP design, based on MC68000 processor and lot of memory for its time (Amiga 500 style...), two old 8bit MC10319 ADCs and fast ECL acquisition logic, providing 10MSPS per channel sampling rate, but with all 4 channels turned on ADC is multiplexed giving 5MSPS per channel. Equipped with two analog, and two “digital” inputs (with lower sensitivity and limited attenuator range, not standard 1-2-5), large CRT and GPIB interface built in, markers, w-form measurements etc... Service manual is easily available but useless, no schematics, just how to isolate mainboard, PSU or monitor problem. Most imminent one is not mentioned at all.


Instrument is equipped with 32K NVRAM battery backup memory to store calibration data. Guaranteed retention time is 10 years, instruments are now over 20, so problem is obvious, question is only when, not if, memory will fail. Memory is old Dallas DS1230 type, not yet obsolete (Maxim still made replacement). Battery failure will loose cal data, prompting error message, also frequently cause some other failures, like ADC fail in self test making instrument useless, not responding to any applied signal at all. Instrument in this condition may appear on Ebay in “for parts only” status, for less than 50$, even20! Calibration can be performed with failed memory, but will be lost when instrument is turned off.


Quick fix: replace memory and run internal calibration. Or, patch it with ordinary 62256 memory, PC motherboard battery and two diodes. You will need to unscrew and dismantle everything to get mainboard out for repair, and some careful soldering on multilayer PCB. Lazy man's way: switch rear panel calibration switch to unprotected, recall default cal data from front panel utility menu, and you will have working instrument. Not fully calibrated, but good enough for normal use, much better than usual modern day plastic toys with screens, called low end oscilloscopes, and slightly cheaper.


I rescued this one for my friend, also i have somewhat newer HP 54601, obtained time ago, but i cannot recommend 54601 as a good decision to buy. 601 is newer generation instrument, with similar performance, lighter and more portable, but Ebay price is too high, better choice can be made for that money. Old 501 however can be very good low budget choice, i hope this post can be useful for someone to make “opportunistic buying” One useful advice is to carefully check instrument condition, this model was frequently used in ATE systems, remotely operated under computer control, so 20y old instrument may appear as new because no one actually physically manipulated it. Watch for CRT screen burn marks, may be visible after displaying same image for 20y. Interestingly, HPIB command was provided to turn off CRT when operated remotely, but apparently no one ever used that feature.


Unfortunately this way of sourcing second hand equipment is not available, or at least not commercially viable in some parts of the world. For example, Belgrade, Serbia, (i’m not Serbian by nationality but live here). You can import nuclear sub if you want, make banking transfer despite no PayPall works but... My last 1500$ bid (instrument for commercial use in company, not for hobby) ended up 2300E when i get it (~3000$, twice!!!), counting unreasonable shipping costs, subcontract spedition, bankster's provision and exchange rates, custom office fees, VAT and what not, typical for lidded off “transition” country. Only way is to buy 20000$ brand new equipment and pay for all the rest, banking sector will offer some help, under conditions rendering armored robbery as a fair business. Via Bosnia may be the way, this particular instrument is purchased in Ireland (!) No quick fix for that part. Also good excuse why i still don’t have ITMD book.

[Davor]

My brand old Hitachi v212 scope came via Bosnia, and it will father your HP's grand children in 20 years time
I'm quite happy to have a real CRO at last.

[bernte_one]

hello

i have ordered a poscope basic 2 this week from slowenia for 59€
today i achieved a poscope mega 1+
it is an usb oszi with some extra functions
the first look is very nice
software ist very good too
i have no big experience with scope
but think its a good offer
http://www.poscope.com/
at the moment you can only see the mega1+ version on the main page banner

the signal generator could be used for coil nulling or?

regards

[brucester]

Would this be suitable for building MD's?

https://secure1.bluecentral.com/emon...p?idproduct=72

[Davor]

Seem as a decent one for all MD purposes

[ODM]

At least some "recent" scopes are rebranded Tektronix and HP/Agilent scopes - likely from the same factories, to boot. Rigol is decent quality, you'll find several good examples of them in use over these forums

[brucester]

sweet, just ordered it :P

couldnt say no at that price :P

[andersk]

Brucester, DS1052E is looking good Oscilloscope. Which version you have selected 50MHz or 100MHz? If the price difference is not much go for 100MHz.

[Tepco]

Forget my post #32 and go for Rigol or Owon. Cheap and perfectly good instruments. Now using Owon 7102, worked with Rigol too (50MHz version “overclocked” to full BW), i can tell any attempt to rescue older scopes is pointless now, unless you get one for free, or nearly for free. Decent sampling rate, deep memory, fancy color screen, interface and all, these things are light-year ahead of old Tek\HP clunkers.

Being employed in service\calibration lab long time ago, my habit to reincarnate some old equipment is just a hobby, maybe good for some other test equipment types, but positively not for oscilloscopes anymore.

[WM6]

Decent sampling rate, deep memory, fancy color screen, interface and all, these things are light-year ahead of old Tek\HP clunkers.

Not in every situations. Did you try to compare presentation composition of some modulated signal (say: 1500kHz modulated by 15kHz) on your Owon with some of Tek or HP "clunkers" and probably you will change your mind.

[Tepco]

I will not. Just for “backup” i still have one old HP1740 and one Tek 465 ready, just in case. Mostly used in some “high risk” situations, fast high voltage discharges etc. in order to avoid damage to more expensive equipment. Best of both worlds strategy works fine, only, 99.8% of time, features available on modern devices is what you need. Consider this post is about decision to buy first scope for DIY construction needs, going to new cheap DSOs seems to be reasonable decision, not denying need to have some old analog instrument for backup or special needs. Best of both worlds is to have them both .

In this particular case, my old HP54601 can have hard time displaying the signal properly without tricks, limited by 10 (20) MSPS acquisition and some 2K memory, but new machines will work just fine. Old analog ones will too, just lacking cursors, measurements, interface and all that.

Same as with MD, proper weapon choice for right target, only here better to have entire armory available.

[darrenk]

was thinking of buying another scope myself, but its been 20 odd year since i used one on a home study tv course, cant blooming remember how to use one and where would you place the probes on a detector, as I am contemplating building a more elaborate kit, just finished the surf pi which was simple apart from a few issues with power and a leaky resistor

[Mark-VA]

here is a nice machine

https://post.craigslist.org/manage/3562211760