Gifted a Krohn-hite 5920 Arbitrary Signal Gen..what am I to do with it? - Page 1
Forum section: electronics / testgear

author: SuzyC
author_rank: Frequent Contributor
timestamp: June 30, 2019, 09:45:39 pm
content: Some friend gave me a Krohn-hite 5920 rack mount size with large handles on front sides.Excellent physical condition, paint on panels like new, no dents or scratches, all buttons ok, etc. Rear panel has also no corrosion or dirt, BNCs shiny, out-ins for everything! Looks like it just popped out of a StarGate Time Machine.EU 220V std large 3 wire AC power connector..just like on a stationary PC power supply.Cannot find free user manual or tech manual..but K-H website says mans for legacy equip. could be bought directly from them.Spec sheet not available, but some USA equip. retailers on ebay show there are at least four units for sale around 500 to 1000 US with 100 US shipping to GNW..and they do list what it can do:10MHz arbitrary (ARB) generator of the 5920 Arbitrary/Function Generator allows the user to construct complex waveforms with up to 16,384 points of time resolution and 4000 counts of voltage resolution. Waveforms are generated by entering a series of voltage levels evenly spaced in time. Waveforms involving straight line segments of any shape can be entered by using the ramping (interpolation) function. Each data point also provides a user programmable TTL sync output bit. 10MHz Arbitrary Generator 16,384 Protectable Data Points Arbitrary Voltage Accuracy: 0.1% Data Point Rise Rime: 100ns Voltage Resolution: 4000 Counts Block Transfer of Data Points Frequency Accuracy: 0.01% Typical Powerful 1000 Step Auto-Programmer 98 Non-Volatile Memory Blocks Multiple/Movable Sync Points Master/Slave Operation Automatic Self-TestWow!100ns Voltage Resolution----------------Now what?

author: ogden
author_rank: Super Contributor
timestamp: June 30, 2019, 10:11:34 pm
content: Sell it and buy equipment which you know how and where to use

author: 0culus
author_rank: Super Contributor
timestamp: June 30, 2019, 10:20:20 pm
content: Or learn how to use it? Arbitrary signal generation can be very useful for debugging if you can catch the signal that caused your device to crash and save it.

author: ogden
author_rank: Super Contributor
timestamp: June 30, 2019, 11:36:05 pm
content: Quote from: 0culus on June 30, 2019, 10:20:20 pmThing is that this device is not usual ARB. It is for automated tests, not bench use. Better sell this box and buy *proper* 10MHz ARB like Rigol or Siglent.

author: Stray Electron
author_rank: Super Contributor
timestamp: July 01, 2019, 02:47:23 am
content: Quote from: ogden on June 30, 2019, 10:11:34 pmI disagree. Experiment with it and learn how to use it. Then decide if you want to keep it or not. Either way it's an opportunity to learn something.I had never used one until I picked up a Pragmatic 2414A last year. It's mainly programmed by mathematical equations and been very interesting to play with programming the equations (and combining more than one of them) and then watching the resulting waveforms on an oscope.If you can't find a manual for the KH generator, go find one for similar models and see how they are operated. There's a good chance that they're similar.

author: Electro Fan
author_rank: Super Contributor
timestamp: July 01, 2019, 03:43:49 am
content: Quote from: Stray Electron on July 01, 2019, 02:47:23 am"Experiment with it and learn how to use it. Then decide if you want to keep it or not. Either way it's an opportunity to learn something."+1

author: jpb
author_rank: Super Contributor
timestamp: July 01, 2019, 11:31:38 am
content: Quote from: ogden on June 30, 2019, 11:36:05 pmThis may be a more "proper" ARB than the Rigol or Siglent - I don't know, but many of the more expensive old ARBs such as ones Tabor produce, have variable time step (clock) as well as different voltage levels whilst the Rigol and Siglent have fixed clocks.Of course the Rigol or Siglent (or Keysight etc) will be easier to set up from the front panel.Unfortunately, as the OP says, it is not easy to find information on the Krohn-Hite 5920.

author: ArthurDent
author_rank: Super Contributor
timestamp: July 01, 2019, 08:16:24 pm
content: Back when this generator was made it was probably a great unit, but that might have been 40-50 years ago. If you don't currently have a function generator it might be worth keeping until you can find a more modern one with far more features, so as others have said, it might be a good learning tool. Also it isn't worth that much no matter what some eBay sellers think and you'll lose nothing by keeping it for a while. The FY6800 available on eBay for $85-$100 has a lot of features and would be far easier and more fun to use than the Krohn-Hite 5920.I have a Krohn-Hite 5910B which is basically the same unit only it has a top frequency of 5Mhz instead of the 10Mhz of the 5920. I modified mine by adding an on-off switch to the front panel because mine only had an on-standby mode which left the power supply and the annoyingly loud fan on all the time. I found that the frequency accuracy was probably about 1% but could be set closer if you monitored the output on an external counter. It can sweep but I've forgotten the sequence of key strokes to make this happen. The newer ones are much more user friendly.

author: Stray Electron
author_rank: Super Contributor
timestamp: July 01, 2019, 08:16:50 pm
content: I found some better pictures of the front panelhttps://www.ebay.com/itm/Krohn-Hite-Corp-Arbitraty-Funcion-Generator-Model-5920-No-Reserve-/163642288792?hash=item2619d72a98%3Ag%3Agw4AAOSwOjZcrSwY&nma=true&si=F23o%252FWT2lQEh3ZDqyTurEUUsmYo%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557and it looks like that for most uses, it would be extremely easy to use. There are push buttons to select Square, Sine or Triangular waves. A keypad to enter the frequency and/or amplitude, a set of keys to select the units multiplier; mega, kilo, milli, micro, nano, then another set of keys to select Frequency, Period, AC peak, AC RMS, DC offset, +/- current, etc. Learning how to use those shouldn't take more than a minute and those should cover 95% of the normal uses. I routinely use a HP 54510 scope and it's front panel operation is almost identical.And you're wrong ogden, this thing is fully operable and fully programmable from the front panel. It's not made just for use by remote control.

author: SuzyC
author_rank: Frequent Contributor
timestamp: July 02, 2019, 01:08:05 am
content: Thanks much to Ogden, Stray Electron and AutherDent!I have powered my 5920 up and found it went from kinda no so good to kinda SNAFU.The rear fan had a sponge filter that was so decomposed that it fell into crumbled particles when removed. The high quality ball-bearing fan is quite loud, especially without a filter sponge. No problem, was easy to fix.The inside of the instrument is spotlessly clean except for a few large particles of the disintegrated fan sponge which I easily removed. No tell-tale smell of burnt components. Nothing seems to be overheated and PCB heatsinked transistors are warm to the touch, while the TO-3's P/S pass transistors mounted on the rear panel make nearby metal too warm to touch.Checking the internal power supply voltages with a scope, I found the clearly labeled -10V supply test point reading approx +10V, while other P/S voltages are correct: +22, +5 CPU, +30V Raw, etc. Large electrolytic caps within do not show prolapsed dome syndrome, thus indicating they are functioning.When I press the CONT and ARB button on the left front panel, I got a clean 20V P-P 200uSec period sinewave centered around 0-V at the 50-ohm main output (with no terminating resistor, just my scope x10 probe)That was a while ago. After attempting to set +/- Offset buttons, things started to go south quickly.After several on/off power cycling, operation has been deteriorating rapidly. Now it will turn on with all the green LED's on the left side of the front panel and other green LED (including the 7-Seg display) are flickering on/off at a fast rate.The unit now is in ICU with a complete loss of control by buttons.Function Generator is now non-functioning.The question is: Does the immediate availability of cheap ebay single-chip function-generator modules or new models of bench-quality ARB/FuncGens make it TTTTTTT *Is it at all worthwhile to try to fix this unit?Would anyone even want to buy it for parts, or even for lab use if I somehow managed to fix it? I have inquired at K-H about the cost and availability of service/operation manuals, even while the only info posted about the 5920 on their website is that it is an obsolete piece of equipment with no suggested replacement. There must be a good reason to that?It is easy enough for used-equipment pirates to offer a few ostentatious instances of this device at high prices when engaging in a type of fishing expedition, but are there any interested parties out there wanting to bite?Just by its super-duper NASA front panel appearance, it would be a welcome component of any SCI-FI movie Control/Operations room!-----------*This thing techno-take-to-the-trash

author: SuzyC
author_rank: Frequent Contributor
timestamp: July 02, 2019, 02:39:38 am
content: Left the unit on for a couple hours and then cycled power again and now I can get the buttons to work!I got it to briefly to output sine/triangle/square waves but then tried to hack operation and pressed other buttons and now its not setup right and it is flatlining.ArtherDent: Can you give me a few instructions on how to use/basic setup for this thing?

author: SuzyC
author_rank: Frequent Contributor
timestamp: July 02, 2019, 12:04:47 pm
content: A quick emailed reply for my request for manuals for the 5920, from the president of K-H hisself, said the cost for a manual is US$ 125, without any description of what manuals would be provided."The cost for the 5920 manual is $125.00 payable by VISA, Master Card,Discovery and American Express."Anyone's opinion: Is this instrument worthy of this cost?

author: tautech
author_rank: Super Contributor
timestamp: July 02, 2019, 12:13:52 pm
content: Quote from: SuzyC on July 02, 2019, 12:04:47 pmA digital copy should be free !

author: SuzyC
author_rank: Frequent Contributor
timestamp: July 02, 2019, 12:24:07 pm
content: Hisself doesn't think so!

author: tautech
author_rank: Super Contributor
timestamp: July 02, 2019, 12:26:27 pm
content: Quote from: SuzyC on July 02, 2019, 12:24:07 pmYou might ask him to check this URLhttps://www.eevblog.com/forum/testgear/gifted-a-krohn-hite-5920-arbitrary-signal-gen-what-am-i-to-do-with-it/