hybridfree/eevblog-posts huggingface dataset:
HP 4952A many different CPU systems in a product - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: February 10, 2025, 09:11:28 am
content: I love to play with vintage equipment, here is my latest score HP 4952AI found 4 different CPU systems inside : Z80, 80C51, 8088. 68008a little video about ithttps://youtu.be/7Vl7zRgqXIM
HP 4953A monitor re-use. - Page 1
Forum section: electronics / projects

author: RetroSwim
author_rank: Contributor
timestamp: August 18, 2014, 04:28:00 am
content: Following on from my posts here:https://www.eevblog.com/forum/testgear/hp-4952a-protocol-analyzer-service-manual/I want to re-purpose this HP 4953A protocol analyser into something cool and retro game related. I've re-furbed the PSU, mapped out the keyboard matrix, and reverse-engineered the green phosphor 9" monochrome CRT monitor. It's a fixed-sync monitor, 60Hz vertical, 25kHz horizontal. It takes +5V, +12V, and four active-low TTL-level signals, one each for H and V sync, a pixel bit, and an intensity bit. The protocol analyser's CRT2 board has a 25MHz crystal on it, so I'd say the horizontal resolution is somewhere around or perhaps just north of 650-700px viewable (allowing 200px or so for retrace, front porch, and back porch).The 25kHz horizontal refresh is too slow to display 480-line VGA signals natively (I'll get back to this later), but should be just right for 350-line EGA signals (with room to spare). My idea is to have a small vintage PC mounted inside the chassis with an EGA card, some simple double-buffering circuit, and a microcontroller circuit to interface with the keyboard.So my question is: Is a FPGA (or maybe a CPLD?) the right tool to build a simple TTL video double-buffering circuit? Writing to the display from buffer A while buffer B is filled, then swap and repeat, it seems simple enough, but I don't know enough about CPLD/FPGA capability to say for sure.I've seen barebones Altera Cyclone II dev boards on DealExtreme, and now seems like as good of a time as any to learn, but I want to know if that approach is going to work before I spend a lot of time learning Verilog or VHDL.

author: RetroSwim
author_rank: Contributor
timestamp: August 20, 2014, 11:02:47 am
content: Well, I've made some progress. The monitor can indeed be used separately to the protocol analyzer brains.Shown here with the CRT2 board removed for emphasis. All the protocol analyzer is doing right now is powering the monitor. Sync and the signal are being generated on an ATMega328P-PU. The code I used is geared towards a VGA monitor, so the front/back porch delays are wrong, and the text wraps around into the H retrace.Next is do design my custom FPGA double-buffering device.
HP 5082-8481 datasheet or specs? - Page 1
Forum section: electronics / projects

author: Co6aka
author_rank: Unknown
timestamp: May 07, 2015, 03:00:33 pm
content: HP 5082-8481, typical HP tiny axial glass encapsulated diode package. 'Net searches turn up a zillion people trying to sell me a zillion, but no sign of specs or a datasheet.Anyone? Thanks!
HP 5087A replacement card design changes - Page 1
Forum section: electronics / projects

author: HalFoster
author_rank: Frequent Contributor
timestamp: December 04, 2023, 03:36:14 pm
content: All-I have recently designed replacement boards for my HP 5087A frequency distribution amplifier – the input preamplifier and pretty much an exact copy of the original, a combined (selectable at build) 10MHz to either 5MHz or 1MHz board and a single wideband amplifier for the outputs.Everything works fine and within the original specifications but before ordering parts for more boards I started rethinking my approach to the whole thing. Originally, I tried to duplicate the original functionality but updating to modern components and streamlining somewhat; after building and testing the trial cards, however, I realized that a different approach might make sense.The signal source will always be 10MHz from a Spectracom 8195A GPS receiver so instead of the general-purpose input amplifier I think it would be better to have it targeted to the input signal with heavy bandpass filtering at 10MHz. The current divider cards mirror the filtering of the original but could have stronger BP filtering as well. Then the output amplifiers could be simplified to just be amplifiers with no targeted filtering. As there are twelve of them that saves considerably on the part cost for a fully populated chassis.So, is there something that I’m missing? From a performance standpoint my feeling is that nothing will be worse and will probably improve. Another consideration that I have is that I currently have a total of 5 of the 5087A units – I’ll probably replace my Brandywine FDA1050 with one of them and possibly keep a second for backup. That leaves at least three that I will sell, and I don’t have enough cards to fully populate all of them. My thought was to include enough of the amplifier cards for free to complete the full twelve slots (blank cards – all through hole construction) so the purchaser could build them or not as they desire. Maybe offer built ones for a profit if anyone wants that, but the designs and the Gerbers I’ll post on the HP groups.io sites file area so I would like to make sure the cards meet the needs of those other than myself as well.Comments?Hal
HP 5212A Electronic Counter 1969 Nixie tubes, neonbulbs LDR driver decoders - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 02, 2022, 02:17:54 pm
content: many of you know this type of 4 bit counter to nixie tube decoder driver,if not have a look :https://youtu.be/HMshrZMT9fMit is a classic problem with this light sensitive elements and neon bulbsnot working anymore after 50 years, some say it is a humidity thing ?Anyways : did any of you try to make a new counter / neon driver ?i mean a 7490 counter and 74141 nixie driver is all each module need,and then it could most likely count 20 times as fast too
HP 5257A transfer osc sampler 18GHz from 1971 - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: March 08, 2025, 11:08:54 am
content: HP 5157A from 1971 can measure frequency up to 18GHz using a sampler, picture attached,they use the harmonics of a sample frequency to take sub-harmonic bites of the measured signal,that signal is now analyzed and then you can figure out what the input frequency is.i did a deep going teardown video of the unit, feel free to look here :https://youtu.be/N0KdJxcazocthere is a lot of ultra tiny special parts, today we would call it alien tech.
HP 5370 processor replacement project - Page 1
Forum section: electronics / projects

author: cncjerry
author_rank: Unknown
timestamp: January 01, 2024, 11:31:12 pm
content: After finding this 5370b for a great deal, I came across the processor replacement project. It's been sort of shutdown for 5yrs. I ordered the boards for cheap, thanks to help from a member here, and struggled with the BeagleBone Black. Biggest wish someone would have told me it boots from the microsd, but depending how a file is coded, flashes the system.I downloaded the latest image, and found that it wont boot if it is set to flash. I turned off the flashing, can get it to boot now. Can't put it in the 5370B yet because I ordered the wrong footprint for the level changer... By the way, I don't have the flashing problem if I use Deb 7.11 image and make my own program. that has pretty much the same results as below. the image used deb 7.9.Issues that I see at this point, if you can remember back a few years:0) Can't get the last published image to flash, so that is a pain, unless my image using 7.11 will work.1) Neither my version using 7.11 or the last using 7.9 has a telnet daemon running. So you can't telnet into the box. It looks like the 7.x debian code apt libraries are screwed up so you can't fix this without some screwing around.2) Neither my 7.11 version or the last using 7.9 have the web server setup correctly so you can't use that access either. Even it you set it up, I looked at the java code and can't figure out what it was doing after a cursory glance.3) If you can't access the box using telnet, html or ssh (that works), then I'm wondering if I can get HPIB data out or control the software?So far, everyone I spoke with had the card in and took it out for one reason or another. I might not even get that far, but it was sort of an interesting experiment and could have given new life to a very old box. Wondering about the image file missing telnet and the web server, both called out in the instructions as working(?)thanksJerry
HP 54501A Digital Oscilloscope 1989 4ch 100MHz test teardown - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: June 21, 2022, 09:32:48 am
content: how about a 4ch 100MHz BW scope.. with only 2Meg samples / sec !!yes, 500nS pr sample in 1 ch modeHP made this scope in 1989, see all details in the videohttps://youtu.be/c3eyTzcAnXE
HP 54645A/D Oscilloscopes Programmer's Reference Manual - Page 1
Forum section: electronics / projects

author: dazz1
author_rank: Frequent Contributor
timestamp: May 08, 2025, 10:52:17 am
content: HiAttached is the HP 54645A/D Oscilloscopes Programmer's Reference Manual.This is available on-line, but only in the Windows .hlp format, a virtually unreadable format since Win XP/8.The attached file is converted to rtf format, readable with most word processors.Ooops.The attached zip file now includes the reference guide.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 08, 2025, 06:50:33 pm
content: The file is 22 bytes.

author: dazz1
author_rank: Frequent Contributor
timestamp: May 08, 2025, 09:59:48 pm
content: HiI made a mistake and didn't include the manual in the zip file. It is there now.I see 11 downloads which suggests others might be interested in programming their HP scopes. It would be very difficult to do with just the programming guide. The programming reference manual includes a lot of information.I have the GPIB adapter and logic analyzer probes for my HP 54645D scope. The LA functionality is useful but somewhat limited. Fit for my purpose, but the user interface is slow and clunky.An example being that you can't read hex values directly. You have to read bits and convert.I am looking into programming the LA part to create a nicer GUI.The application is restoration of obsolete 1990's test equipment.So I am looking and spending weeks programming an obsolete 25year old scope so I can save a few minutes effort using the LA part of the scope.The rational approach would be to dumpster the obsolete test equipment which would negate the need for the LA scope and buy new test equipment that didn't need fixing.If I did that, I wouldn't need any test equipment because I wouldn't have anything to fix.I have looked at buying a proper LA from the USA, but most are sold without probes, and the cost of shipping over the USA border and across an ocean is prohibitive.With most modern comms serial, and modern scopes able to decode these, the traditional logic analyzer is a relic of the past.I still want one.
HP 55300A GPSDO - Page 1
Forum section: electronics / projects

author: deepskyridge
author_rank: Regular Contributor
timestamp: November 17, 2016, 09:49:58 pm
content: I picked up a HP 55300A on EBAY for parts or not working.Unit works fine, I am looking for some documentation.I have the users guide, an looking for the Programming docs.I will do a teardown of the unit soon.ThanksGary Neilson
HP 59309A Digital Clock and K10-59992A - Page 1
Forum section: electronics / projects

author: markgreco
author_rank: Newbie
timestamp: August 06, 2021, 01:37:11 pm
content: My first post here!I own a HP digital clock HP 59309A and can find lots of information on it.What I can’t find is anything on the K10-599992A battery backup.I’m trying to make a replica as they are close to impossible to find.HERE IS WHAT I DID.The front faces on vintage HP Equipment vary in color slightly I found a Tamiya Color Spray Paint that is pleasing and matches both the dark and the light face colors is called AS 16 Light Gray USAFDecals are made using Hobby Lobby Water Slide Decal Paper and my regular printer. First print out everything on regular paper and lay it out on the instrument. Do this, look at it, take a break, look at it, take a break.. Patience is the key. then commit to the decal paper. DON'T FORGET TO USE TAMIYA CLEAR AFTER PRINTING AND BEFORE INSTALLATION OF THE DECAL.https://www.hobbylobby.com/Crafts-Hobbies/Model-Kits/Tools-Adhesives/Water-Transfer-Decal-Paper/p/1158. WATER SLIDE PAPERYou can NOT print white so i made the decals a gray color (RGB 204 204 204) using Microsoft Publisher and the letters are transparent.Any hole filling is done using JB weld. Cover the hole with tape on the back side fill in the hole with the JB Weld and let it sit for 24 hours before sanding. After sanding use as many coats of primer to achieve a glass like surface. then I do 2 coats of color wet sanding with 400 grit sandpaper between coats.I used Tinkercad to design all the parts and my Anet A8 Printer and COEX PLAHere is a link to the project Battery Back Uphttps://www.thingiverse.com/thing:4890680My other Stuff for HP Greco Stuffhttps://www.thingiverse.com/mark_greco/designs
HP 616B UHF Signal Generator 1800-4200MHz test teardown - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: June 29, 2022, 08:39:05 am
content: HP 616B UHF Signal Generator 1800 4200MHz test teardownthis unit is 50 years old, still works, and is very accuratesee here how they did ithttps://youtu.be/21ktrYxy5II

author: Maurizio1957
author_rank: Contributor
timestamp: June 29, 2022, 03:27:19 pm
content: Where do you find stuff like this in so pristine conditions??I have one of this and also other old HP gears and all are a blob of oil , grease and dust inside....73, Maurizio IU5BEC

author: oz2cpu
author_rank: Frequent Contributor
timestamp: June 30, 2022, 08:53:26 am
content: thanks, some people / companies do take very good care of their old vintage equipment,i also got compleetly coroded units, defective, and not worth a repair restore,in a few days i will release a such sad video example, stay tuned, or subscribe.

author: Stray Electron
author_rank: Super Contributor
timestamp: July 01, 2022, 05:35:13 pm
content: I had a chance to pick up one of these for next to nothing about 15 years ago. It was in mint condition but I didn't have a use for it so I passed on it. But I still regret not buying it. Man that thing was a beast!

author: oz2cpu
author_rank: Frequent Contributor
timestamp: July 04, 2022, 09:21:43 am
content: i actually picked up all 3 models :-) that is a full car load for my size car, HP614, HP616, HP618at the moment i try to repair the HP618 3.8 TO 7.8 GHz typemechanical issues in attenuator gearbox, all grease turned to epoxy, what a pain to fix.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: July 04, 2022, 04:38:06 pm
content: Those things are a mechanical tour-de-force. The grease-to-epoxy problem can be dealt with using a hot air gun, alternated with WD-40 or naphtha. I have to say I detest videos, not having the time or patience to watch them. It would be great if you posted some stills here for us old curmudgeons.

author: oz2cpu
author_rank: Frequent Contributor
timestamp: July 05, 2022, 11:41:41 am
content: about videos, use the fast click forward, or pull the time slider to a point where things of interest are shownI cant offer to post a lot of stills too, and to publish them on a web page and to maintain it,I also like the possibility of comments, people can post links and such too, and even comment on each other comments,this way all and help all to get more insight
HP 618C SHF Signal Generator 3800 7600MHz test repair teardown - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: July 08, 2022, 02:57:57 pm
content: this really nice old generatorHP 618C SHF Signal Generator 3800 7600MHzgot a few problems, the schematics i find dont match my version, darn it.. not always easy :-)but I did manage to get some GHz out of itvideo herehttps://youtu.be/EBFIPf2ax9E
HP 6227B Reference supply analysis/design question - Page 1
Forum section: electronics / projects

author: kg4arn
author_rank: Unknown
timestamp: March 31, 2014, 06:08:30 am
content: This is a partial schematic is for an HP 6227B 20V 2A dual supply. It shows the reference regulator that powers the control circuitry for the main supply.What are the purposes of R46 and R44 in this circuit?Does R44 provide negative feedback to turn off Q14 and Q15?Does R46 lower the output impedance to aid stability?

author: quantumvolt
author_rank: Frequent Contributor
timestamp: March 31, 2014, 09:06:45 am
content: R46 is for start-up and has no other function. When power is turned on, there is 0 volt on the circuit output. So Q14 is closed and stay closed (without R46). With Q14 closed the Emitter and Base of Q15 is at the same potential. This keeps Q15 closed. So unless you put inn the shunt resistor, there is no current to fire up the supply.R44 is a bias resistor to level shift the Base of Q14 to the working voltage level of the Collector of Q13 by feeding current to R48. Often a Zener is used for R48, but in this case where you have a constant precision output 18.6 V from 2x 1N825 (or better) temperature compensated avalanche diodes (Zener) in series, combined with the sampling divider Z2L, R52 and Z2J - a resistor divider R48 and R44 does the same job.

author: kg4arn
author_rank: Unknown
timestamp: March 31, 2014, 11:25:27 am
content: Thank you quantunvolt. I can see it now with your explanation.
HP 6920B and AC ripple? - Page 1
Forum section: electronics / projects

author: Crambone
author_rank: Frequent Contributor
timestamp: November 06, 2023, 11:24:36 pm
content: I received a non working 6920B and since have gotten it working but needs calibrating. I installed all new good quality low ripple electrolytic and I’m still seeing more ripple than one should.SET UP:Function “DC”Output Dial “500”Range “1”RANGE. DCV. AC RIPPLE1. .5839 1.97mV10. 6.0 46.9mV100. 59.3 0.04V1000. 622 19.6VacI know it needs calibration but wanted to settle out the ripple first or is this normal for this unit?Link to manual,http://hparchive.com/Manuals/HP-6920B-Manual.pdf

author: RolandK
author_rank: Regular Contributor
timestamp: November 17, 2023, 07:52:06 am
content: there is a manual from 1967 fromhttps://www.keysight.com/de/de/assets/9018-03154/user-manuals/9018-03154.pdf.The answer is at page 42. There are oscillograms.Page 25 to 31 is troubleshouting and calibration.

author: RPP
author_rank: Contributor
timestamp: November 25, 2023, 11:46:15 pm
content: @Crambone I picked up one of these a few weeks ago and plan to work on it in the spring. Do you happen to have a list of capacitors you used? I'd like to get them on order so i have them on hand when i'm ready to start mine.Rich
HP 803A VHF Bridge Impedance And Angle  - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: June 26, 2022, 12:42:06 pm
content: any one know this one ?very impressive unitany ideas why my output level is a bit low ?like 20-30dB too lowsee all details herehttps://youtu.be/oHWhDqUBWrM

author: jwet
author_rank: Frequent Contributor
timestamp: June 27, 2022, 05:23:35 pm
content: Wow- that is a beautiful instrument. I graduated in EE in 1982 and we had things like this in my RF course (EE353 at Illinois). I remember using General Radio wheatstone bridges at lower frequencies that worked with buik L's and C's. At higher frequencies, there were slotted lines used up to a gigahertz. This is basically a slotted line that is bent into a circle. Not much can go wrong. I can only imagine the contact to the slotted line (the wiper) is dirty but I don't think even that is a problem. They are not lossless at all- the -40 db min insertion loss is a minimum and with a matched load, it could be well below 80db- this is your return loss and a very good match is -50 or more meaning your detector output would be 90 db below your input. I think its essentially working. In the old days, you would use bridges with a radio receiver- they can easily have a sensitivity down to -120 db narrow band. This is way before spectrum analyzers. This is the predecessor of the VNA- imagine those little $50 VNA's do what this does. Button it and use it- its working. In the corner of my all university lab, there was a brand new 8505 Network Analyzer that displayed Smith charts with little acetate overlays for the scales. After you spent the semester doing all this stuff, they would show you the VNA and you'd be amazed. I think its working!

author: oz2cpu
author_rank: Frequent Contributor
timestamp: June 27, 2022, 10:06:15 pm
content: thanks a lot for your time and comment,I read the manual about insertion loss, that is why i dare to ask about the values i see,there is no way the resistors or couplings can be damaged, so it must simply be an error in the manual ?back then, sensitivity was an issue, maybe they used a much more powerfull signal generator ?
HP 8690B sweep generator, why 2kV regulated supply, teardown video links - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: April 21, 2022, 09:24:06 am
content: i just made a deep teardown of an HP 8690B sweep generatorthe main unit is Tube-Transistor based hybrida thing that i found very special is the regulated 2kV supply made by two large pentodesreally ??no other way existed at the time ? to make this product work ? but to use VERY high voltages ??the resulting voltage control sweep signals used by the rf plug in, is very low.. so that is why i found this very off, and very complex.feel free to post comments here, or on the videopart 1https://youtu.be/IhKC49kEaXgpart 2https://youtu.be/WrdIDoIJBvkpart 3 (plug in module 0-110MHz)https://youtu.be/c_Z2QxXNruA

author: woodchips
author_rank: Frequent Contributor
timestamp: April 21, 2022, 06:42:17 pm
content: Didn't they use backward wave oscillators to start?Not nice to work on.
HP Agilent spectrum analyzers - where is the chart with model numbers - Page 1
Forum section: electronics / projects

author: Merlysys
author_rank: Regular Contributor
timestamp: September 06, 2020, 04:22:38 pm
content: I am looking into experimenting with spectrum analyzers that can do at least upto 2.9Ghz.I thought higher the model number the higher the GHz, but I now see they are generation based too.Here are the 8560 series. What hardware boards/sections do they share? Maybe not all models but some of them perhaps.8560E 30 Hz - 2.9 GHz8561E 30 Hz - 6.5 GHz8562E 30 Hz - 13.2 GHz8563E 30 Hz - 26.5 GHz8564E 30 Hz - 40 GHz8565E 30 Hz - 50 GHz
HP DPS-1200FB power supply wont stay on. Help w/diag, please. - Page 1
Forum section: electronics / projects

author: VoltJesus
author_rank: Contributor
timestamp: August 13, 2017, 10:16:27 pm
content: Ok gentlemen, I am requesting technical assistance on an HP DPS-1200FB server power supply.Now I bought 2 of these several months ago. I tested both with a 1k resistor on pins 33 and 37 to make sure they were not DOA after the shipment came in.Both units showed 12+ volts when checking the outputs, so I thought all was good. I did not have anything 12v I could use as a load to test them for max output. Never considered that they might fail to operate, even after I saw both of them power up and show 12v on the outputs.Ok, fast forward to a few days ago. I finally finished building my massive battery pack, and was in the stage of building my charging setup.Since the charge controller I am going to use works more efficiently at 24v than at 12v, I needed to modify one of the power supplies so they could run in series.So I took one apart and did the "output float mod". Finished it up and it works fine. I've even charged my battery pack (although, much slower) with just the one supply running 12v into my charge controller.The one that I did not touch refuses to power up. Now, to be specific, when you attach a resistor to pins 33 and 37, it powers up for a brief moment, then the voltage starts to drop off. Seems like there is a safety built into one of the boards that shuts it down. Why that is, I have no idea.I've tried to do some searching to see if there was any way I could diagnose the issue, but I am coming up short.Is there anyone that knows about these supplies that could shed some light on what I could check? Hoping I did not get a DOA unit, as it has been several months since I bought them and I doubt the ebay seller will do anything about it.Oh, and I've tried using different value resistors, as I've read there are some of the DPS-1200's out there that required something other than 1k ohm. I've tried 65ohm up to 1.2k. Same behavior with all. Also, when it does power up for a short while, the green light is very dim, where as my other unit the light is good and bright.Any tips?
Hp dps-700gb power supply - Page 1
Forum section: electronics / projects

author: rcfanas24
author_rank: Newbie
timestamp: April 10, 2013, 04:39:34 am
content: Hello guys, trying to found about this power supply any info about (pin out) to make it working, but there is no info at all so maybe someone can help me ? Thanks

author: ddavidebor
author_rank: Super Contributor
timestamp: April 10, 2013, 05:10:26 am
content: It has not a standard hp name... Never heard anything like this...

author: amspire
author_rank: Super Contributor
timestamp: April 10, 2013, 05:33:37 am
content: You are not talking about this D-Link power supply?http://www.dlink.com/uk/en/support/product/dps-700-589-watt-redundant-power-supply-for-d-link-managed-switches

author: rcfanas24
author_rank: Newbie
timestamp: April 10, 2013, 06:14:54 am
content: im talking about thishttp://www.ebay.com/itm/HP-Power-Supply-DPS-700GB-411076-001-/160749039959its quite powerful server power supply(56A at 12V), just need short some pins to start it up.

author: amspire
author_rank: Super Contributor
timestamp: April 10, 2013, 06:42:27 am
content: That is a power supply for a HP Proliant DL360 G5 server. It is just a 700W PC supply, and it will probably work in a similar way to other PC supplies. It will have a standby supply and a control line to turn on the main supply. It is probably designed so that two supplies can work in parallel.If you get the service manual for the HP server (downloadable from the HP website), it will probably have the pinout of the supply. If you need more information, just look for information on how PC supplies work.

author: BravoV
author_rank: Super Contributor
timestamp: April 10, 2013, 08:07:01 am
content: If I'm not mistaken, that is a hot pluggable power supply, if it is, doubt you can power it on just by simple shorting some pins.There is a chance it might use a bit more complex protocol to talk to/from supervisory circuit at either sides psu or computer to enable the final power output.

author: rcfanas24
author_rank: Newbie
timestamp: April 10, 2013, 03:55:19 pm
content: i found thishttp://www.rcgroups.com/forums/showthread.php?t=1005309&page=50but just only 1 place, i don't wanna make it burned
HP / DYMEC DY-5731 X-band signal generator schematic ?? anyone - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 21, 2022, 11:14:48 pm
content: I just scored this one :-) it is a live, all bulbs glowbut there is no output, i got filament on magnetron, and the filament is at -500 to - 700 V DC potentiali expected that since that is most likely also the cathode, right..but the anode is also at -500 to - 700 V DC , yes this type magnetron got anode wire tooso that explain my missing output,it is a very big and heawy unit, it is very hard to track and trace each signal / voltage supplyI could use a schematic, any one ??

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 21, 2022, 11:27:26 pm
content: here are few pictures from different anglessuper cool unit, could be nice to see some output,i am tempted to try feed it some anode voltage from an external sourcejust to see if I get output

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 21, 2022, 11:28:08 pm
content: more pictures

author: artag
author_rank: Super Contributor
timestamp: October 21, 2022, 11:35:42 pm
content: First time I've seen an actual Dymec piece, with the inverted logo

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 22, 2022, 01:40:26 am
content: still no luck finding anything that is defective in this unit,no matter what i check, all do exactly as expected, but where is my high voltage ??maybe the quest is to find data about the magnatron / Reflex Klystron ?it is called VARIAN V-58Call i find is this, ebay listing very good pictures,https://www.ebay.com/itm/123942554985it looks like the magnet is not a part of the red part,also this linkhttps://www.radiomuseum.org/tubes/tube_v-58c.htmlno pinout no voltages no nothing..

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 22, 2022, 09:58:09 am
content: NEWS: i nice dude called John posted to me in the FB grout i take pictures of electronic partsSO what this say is the filaments should be arrounf -320 relative to chassis, and the tip (anode) should be +500Vi got 6.1V DC between the filements and the red top go hot very hot very fast, but the anode is also negative, about -400 V so that explain why i got no output

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 22, 2022, 04:48:11 pm
content: the klystron does in fact draw the 60mA at 500V as specified in the datasheet,how ever : NO RF OUTPUT

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 22, 2022, 04:49:00 pm
content: more pictures

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 23, 2022, 10:26:01 am
content: little short video released about this unithttps://youtu.be/mzWN97OITj8
HP E3610A "DRIVER" Questions - Page 1
Forum section: electronics / projects

author: ZeTeX
author_rank: Frequent Contributor
timestamp: March 02, 2016, 07:10:45 pm
content: Hey!I'm looking at the old HP3610 PSU, and I have a few quastions about this part:This is the driver for the pass mosfets, But my questions are:1. Why do they need L1 ferrite bead? I guess it is to filter some EMI from the traces but I'm not exacly sure if this is really gonna help something..2. What does R3+R5 combination does? Without it the driver wouldnt work, But what is the propose of those 2 resistors?3. R44+C23 or R45+ C22 combination, I guess it is for stability but what exacly those it do? Why do you need it?Thanks for your time.

author: Cerebus
author_rank: Super Contributor
timestamp: March 05, 2016, 01:32:15 am
content: L1 is probably there to stop Q2 turning into an oscillator - those general purpose small signal transistors have more bandwidth than is helpful sometimes (The 2N2222A, which I think that is, has an Ft of 300MHz).The resistors are probably providing a bit of isolation from the MOSFET's input capacitance - so as you suspect, a stability thing.The capacitors are probably providing a bit of AC feed-forward to speed up charging the MOSFET gate capacitance on rapid changes.I'd have to spend a fair bit longer looking at the full schematic to remove all the "probably"s from the above.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: March 05, 2016, 03:19:19 pm
content: HelloI remember i have re-drawn this schematic to be specific to the E3610A circuit ,i have paid close attention to the service manual and the E3610A i have had in my hand, there are few components that are not populated in that specific model. try and figure it out and simulate it on LT-spice .Next week i'll search my notebook and upload picture for you .
HP E3620A power supply clone oscillation problem - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: December 13, 2016, 10:57:18 am
content: Hi guys,I build a HP E3620A power supply clone and it works good expect one issue. I used two mosfets in parallel. when I connect one mosfet the circuit the circuit works good but when I connect the second mosfet I got severe oscillation in the output. I don't know what is the cause please guide me.regardsN.Baskaran

author: Kleinstein
author_rank: Super Contributor
timestamp: December 13, 2016, 01:41:48 pm
content: Having two MOSFETs in parallel, there is a slight change to get higher frequency oscillations (e.g. 100 MHz range) from parasitic inductance. Usually one should have resistors in the 10-50 Ohms range in series to the gates, rather close to the MOSFETs.The second MOSFET also adds capacitance and thus slows down the output stage. This could be enough to make the regulator loop oscillate. So adjustment of the compensation to slower or less gain would help in the case. With a fast regulator circuit the tricky parts are parasitic inductance and inductive coupling. So the circuit schematics is not enough also the layout and what type of caps is used can be important.Using 2 MOSFETs parallel for linear operation is tricky: is might work with close matched FETs (same waver) of a type really made for linear operation or a very old type. However load sharing may not be very good: at high power the current will shift towards the hotter one.

author: prasimix
author_rank: Unknown
timestamp: December 13, 2016, 05:18:31 pm
content: How much current you'd like to have and in which in/out voltage range when you wants two mosfets in parallel?
HP E3620A power supply clone out voltage sense problem - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: May 07, 2016, 03:27:29 pm
content: Hi guys,I build a HP 3620A power supply and it works fine. I used PIC16F1783 to sense the output voltage and current for displaying parameters like output voltage , set current limit , actual current . I power the micro-controller board from an isolated tap from the transformer and it grounded to the control circuit ( power circuit positive output terminal). I used voltage divider to sense the output voltage .I connect a 5.6K resistor and 860R resistor as a voltage divider but after connect to the circuit the 5.6K resistor value drops to around 1k and oscillating around. I tried different combination but the same result. can somebody trace out what is the problem. well thanks in advance

author: Kleinstein
author_rank: Super Contributor
timestamp: May 07, 2016, 03:36:33 pm
content: As normal resistors don't oscillate it's likely the regulating circuit that oscillates. Like amplifiers with feedback voltage regulator can end up oscillating quite easy. So my guess is some king of coupling from the divider was enough to make the circuit oscillate. For a fast loop the layout can be critical, so it might nor take much to make the circuit oscillate.
HP E3630A triple dc supply design error found and solved - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: July 09, 2023, 09:39:52 am
content: if you own one of the HP powersupplies in this series,please check its load drop curve with a scope, most likely yours got the same problem,it is very easy to fix, all details hereit is a very nice supply i am super happy about it, so it is clearly worth fixing it,so it is nice and stable under pulse load conditions.https://youtu.be/Tyw93FL90go
Hp Harrison 6200b power supply Manual Request - Page 1
Forum section: electronics / projects

author: resistcircuitresist
author_rank: Contributor
timestamp: June 28, 2012, 11:10:01 pm
content: Looking for the hp/Harrison 6200b Power Supply Service/user manual and parts list. Does anyone have this?

author: oPossum
author_rank: Super Contributor
timestamp: June 28, 2012, 11:22:00 pm
content: 6200B Operating and Service Manual

author: resistcircuitresist
author_rank: Contributor
timestamp: July 06, 2012, 04:51:48 pm
content: Here is the operating manual. The other one is parts/repair.Manual

author: desirider
author_rank: Newbie
timestamp: July 06, 2012, 10:34:38 pm
content: Amazing! I recently got the same power supply. It works great for a 40 year old power supply.
HP-HIL Keyboard Design - Page 1
Forum section: electronics / projects

author: andybarrett1
author_rank: Regular Contributor
timestamp: January 21, 2021, 10:48:27 am
content: Hello all...An interesting project has come my way.... To design a bespoke keyboard outputting a few function keys and trackerball via HP-HIL to an old HP Workstation, There are 10 needed in totalHas anyone done similar or have any ideasThank you for readingAndy
HP 1200W server supply Mod HSTNS-PD30 Hack - Page 1
Forum section: electronics / projects

author: mamundsen
author_rank: Newbie
timestamp: February 02, 2023, 07:15:12 pm
content: Working on a HP 1200w server supply DPS-1200 SB A HSTNS-PD30 and here is how I modified it to put out ~13.6 to 14.2V. I added a 22k to the voltage adjust pot and ground, 18k will get you higher V. On the back of the vertical board is a LM393 comparator (ST393A) I added a 56k resistor to pin 3 and ground to increase the OVP. you have to unplug the fan connector to see the 393. This mod should also work on HSTNS-PD29 as it has the same vertical board. I am posting this as there are other posts and mods on these power supplies, but not on this model in particular. Cheap price, good return from these HQ supplies!

author: RockenRanger
author_rank: Newbie
timestamp: April 12, 2023, 11:21:06 am
content: I have some of these server ps. My problem is when I to add the resistors. The ps will not turn on. But if I disconnect them the ps comes on when plugged in. I'm still trying to figure out what I'm doing wrong.

author: mamundsen
author_rank: Newbie
timestamp: April 12, 2023, 01:38:13 pm
content: not sure, you may need to adjust O.V. pot as O.V. may be out of spec. under voltage may be out as well, take a pic of your pots , measure and tweak , I have only tested with 2 power supplies, putting them on a dead 12v batt causes them to shut down

author: MikeS63
author_rank: Newbie
timestamp: May 23, 2023, 06:30:52 am
content: Hello,I have the same case after I've repited you experience. I understad that without more detail information it's difficult to give the advice what to do in this particular case.But is it possible to share technical information about the powersupplier?The protection is triggered, I want to understand exactly what each of the two variable resistors on the side panel regulates.Thank you in advance.

author: axm1955@yahoo.com
author_rank: Newbie
timestamp: January 05, 2024, 03:02:49 pm
content: Morning guysAnyone knows the value of the V adjust pot? I manage to damage mine. Any help greatly appreciated

author: coromonadalix
author_rank: Super Contributor
timestamp: January 05, 2024, 03:09:42 pm
content: normally even if the wiper is damaged or removed, try to measure between the 2 nearest pins on one sideshould give say 1k 2k 5k 10k etc .....
HP HSTNS-PL11 24vdc output - Page 1
Forum section: electronics / projects

author: l7777
author_rank: Newbie
timestamp: September 10, 2022, 06:24:48 pm
content: Greetings. I've got a number of RC related things that would like 24vdc and a number of watts below the 900 that this can output. Would it be possible to modify the HSTNS-PL11 to output the 24v directly? I've seen the info on adjusting OVP and output but no one has tried to really increase the voltage beyond ~15vdc. Obviously the output capacitors would need replaced to handle the extra voltage but are there other components that would prevent/be unhappy about said output?I know I could run two of them in series to get 24v and 1800 watts but I don't need that much wattage and would be carrying around a fair amount of extra weight. The other option is trying to find a boost converter that could handle the job. Problem is most of them are relatively low wattage and questionable quality. Not sure I'd really find one I could trust to even do 600 watts. Same goes for the available off the shelf 24vdc power supplies I've seen without spending lots of $$. Low wattage, questionable quality, and usually a fair bit larger than these.Yes this is probably ill advised and definitely can be dangerous as we're working with high voltage AC and low voltage but high amperage DC.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 10, 2022, 06:34:26 pm
content: Many if not most HP server PSUs use a full wave configuration for the output, you could add some power Schottky diodes to turn it into a full bridge rectifier. It would still be a pretty big modification and just getting a 24V PSU for a 3D printer would likely be easier.
HP HSTNS-PL18 server PSU strange noise - Page 1
Forum section: electronics / projects

author: OpaHoppenstedt
author_rank: Newbie
timestamp: July 03, 2021, 12:49:04 pm
content: Hello everyone,I tried to increase the output voltage of an old HP server power supply to 13.8V.The model number is HSTNS-PL18 rated at 750W and I found two ways to do thaton the web.The first involves bridging a resistor next to the voltage setting pot. That worked butwhen I hook up my little ICOM IC-7300 transceiver and slowly increase HF power thePS starts to make a strange noise at about 12 amps and higher. The higher thecurrent the higher the pitch and louder the noise. To me it sounds a bit like arcingand this makes me quite nervous.I thought that maybe the PSU picks up HF from the transmitter. So I got me an electronicload and the result is exactly the same.So maybe the PSU is defective. I got me another PL18, did the same mod but exactly thesame noise starts, although this time at 25 amps.Removing the modification back to the original 12.3V I can draw 400W, the max my ELcan take, and both PSUs remain completely silent.At this point I am looking for advise.- where does this noise come from?- will the PSU go up in flames if I ignore it? would my transceiver be at risk?- are there better ways for modification or some of the other pots to change?Thanks for reading.73, Wilhelm

author: eblc1388
author_rank: Frequent Contributor
timestamp: July 03, 2021, 04:09:51 pm
content: It is possible that 13.8V, your are operating the power supply very close to the output overvoltage shutdown voltage level.Try reducing the 13.8V output to 13.4V or lower and check if the strange noise go away. This slight voltage reduction should not have much impact to the IC-7300 transceiver RF power output.

author: OpaHoppenstedt
author_rank: Newbie
timestamp: July 04, 2021, 12:19:33 pm
content: Many thanks for your kind reply.Overvoltage protection does not seem to be a problem here,at least not as long as there is no load. I turned the voltageup and could easily get to 14.5V. I stopped there not tooverdo it, but it could go higher.You are right, the noise went away when I reduced the settingto 13.4V. With a load of 400W the voltage then drops to 13.2V.While the IC-7300 works fine at this level I have some othermobile transceivers for 144/430MHz and those really seem tobe designed for the higher voltage in a car. Therefore I hadhoped to reach the nominal 13.8V.I tried the PL18 because it was available at a reasonable pricebut I am open to alternatives. The PSU should be compact, quietand be able to deliver 50 amps or more for some hours.So if you are aware of some other brand/model that can do thisI would appreciate to hear about it.Best regards,Wilhelm
HP J9738A / DPS-550QB 54V 575W PSU current sharing & pinout - Page 1
Forum section: electronics / projects

author: Fivefold
author_rank: Newbie
timestamp: May 08, 2024, 08:15:40 pm
content: I managed to get my hands on twoHP J9738A / DPS-550QB Apower supplies, manufactured by Delta Electronics. They output about 54V 10.5A as well as 12V 2A. Apparently they are intended to be used in HPE Aruba Networking 2920 switches, esp. for Power-over-Ethernet.I don't intend to use them that way, but rather as separate power supplies. I know that these server-type power supplies can be easily turned on by shorting two pins and/or adding a resistor (seehttps://makenotes.de/2020/04/turning-on-a-hp-dps-750rb-server-power-supply/).Unfortunately I cannot find a proper datasheet for these PSUs. I'm especially interested in the pinout as well as if they allow current sharing/load balancing. Some supplies allow this by simply connecting the outputs together. Some need additional ORing diodes if they are not already included in the power supply:This is a similar-ish power supply datasheet by murata, that also seems to be using the standard server PSU format, but I don't know if this is 1:1 comparable to the HP one regarding pinout and current sharing.https://www.murata.com/products/productdata/8807027081246/d1u86p-w-1600-12-hbxdc.pdf?1583754811000.Does anyone know where this information can be found or alternatively, how I cansafelytest for it?

author: Charget
author_rank: Newbie
timestamp: June 24, 2024, 08:01:01 pm
content: Hey,did you find anything new?I will maybe get the same psu in the next weeks and my plan is to turn it into an adjustable bench power supply.

author: Fivefold
author_rank: Newbie
timestamp: June 24, 2024, 08:55:02 pm
content: The pinout seems to be the same as in the murata datasheet, at least concerning turning on the PSU. I haven't tried out if load balancing works since I don't have an immediate need for it and don't want to break my two units.Note that if you intend to use this for a bench power supply you will want to use a different fan, or open the case and design your own cooling solution (since it's hard to find silent 40 mm fans, especially ones with high static pressure). I didn't expect the fan to be this loud (and had hoped it would be off when idling).The current fan is a Delta FFN0412UHN and isveryloud. Louder than any bench equipment and definitely uncomfortable for extended periods of time. It's always on at least 50 % PWM, regardless of load. If fan speed rises it becomes louder than a hairdrier! I have only simulated this by injecting a PWM signal, since I don't have a load capable of sinking several hundred watts, so I don't know at what loads temperature rises enough to warrant a fan speed increase.
HP Moseley Autograf 2D 2AM analog XY pen plotter teardown (1970) - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: May 07, 2022, 08:25:44 am
content: it was so much fun yesterday i got this one..it is from 1970:https://youtu.be/HY3NB__jTU4the video show all details about the way it works, super cool linear potmeters for position feedbackand also see the wires and wheel

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: May 07, 2022, 04:06:18 pm
content: I still have one very similar to that. Really cool devices, including the high voltage paper attraction method. Also have a few linear chart recorders. Took my small pen plotter to the dump some years ago because I couldn't come up with a reasonable use for it, though I did draw and etch circuit boards with it at one time. I've also got a General Radio chart recorder that's fast enough to record audio room delays. The drive mechanism for the pen is a long travel voice coil with linear pot feedback. Built like a brick you-know-what! Pretty much useless these days. All these mechanical devices were clever and no small amount of design effort went into them. Alas, a modern PC and printer can do everything as well or better. I do think modern engineers could learn a lot by studying this old stuff, in fact it ought to be required!

author: oz2cpu
author_rank: Frequent Contributor
timestamp: May 09, 2022, 08:16:48 pm
content: Thanks Conrad.That point is EACTLY why i keep making all the videos of fun old and new stuff containing cool inventions or solutions :-)feel free to spread the word on my youtube and specially the teardown playlist,at the moment i release a new video every day.

author: oz2cpu
author_rank: Frequent Contributor
timestamp: May 17, 2022, 08:08:07 am
content: see how much happened in 20 years !the first one , the Mosley was from 1970..and this "new" one, is from 1990https://youtu.be/YT-qD2ezhBI