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8714ES - Network Analyzer - Can it be converted from 75ohm to 50? 22
Good day I hope you are Ohm for the holidays! I recently got an 8714ES - Network Analyzer - I plan on using it for Antenna design / filter tuning and Amplifierd qualifications for RF microphone work. But on closer in spection it is setup and has the calibration kit for 75ohm- (it mainly did video equipment testing) Can it be converted from 75ohm to 50ohm? IS there anything I can do externally to make it behave like a 50ohm device? Thanks and Regards - I really apprecite the hivemind here. Anthony
Розпочато Anthony Kuzub @ · Останніх @
HP3336B synthesizer/level generator 2
Hi all, I'm attempting to repair a hp3336b and have found it has a replacement control board (03325-66516) fitted. This is not documented in any of the service manuals I can find, but is referred to in 'service note 3325-A21' or the service manual change sheets for the 3325 generator (the 3325 generator can also use this replacement control board). Does anyone have information on this newer control board? Regards, Waz
Розпочато Warren @ · Останніх @
HP 3561A DSA CMOS battery replacement
Hi all, I have a late version, serial number prefix 29xxx, 3561A that is in great shape but the CMOS battery is a bit low and Id like to replace it. Its a 3.0v battery about the same size as a AA. Rather than the battery being on the A65/66 card, its on the A40 CPU card. I found this VARTA Lithium Manganese Dioxide 3v AA sized battery in stock and was wondering if this would be a good candidate for the CMOS backup. It appears it should fit and it has axial leads which will simplify things. I'm just not sure of the long term viability of the battery chemistry. https://www.master-instruments.com.au/products/54720/craa-cd.html
Розпочато Damon - KJ7E @
free PCL to BMP converter? 26
Hi, does anybody know of a free tool to convert a PCL printout data stream as produced e.g. by the HP859x SAs to some easily readable graphics format like BMP? I know I can use the KE5FX plotter emulator to obtain plots, but some instrument screens (e.g. list of cal constants) won't plot and only show on the screen printout. Thanks, Tom
Розпочато tom_iphi @ · Останніх @
Measuring the impedance of a lithium ion cell 76
As part of an EMI investigation, I was asked if I could find a way to measure the reactance of a lithium ion cell over the range of 10 kHz to 20 MHz. Later I will need to measure a module consisting of a series-parallel combination of these cells. The cells are 21700 cylindrical so will have very definite capacitive and inductive components. The impedances will be low, in the tens of milliohms. I am not sure how I can do this. I tried simply hooking up to a 3577A and test set (knowing the test set only goes down to 100 kHz) but the cell simply looks like a short (of course). Does anyone have any thoughts on how I can do this measurement? I have other gear to amplify and so forth if a custom setup is needed (likely). Has anyone been able to make a similar measurement successfully? Peter
Розпочато Peter Gottlieb @ · Останніх @
Several problems with Agilent 54810 7
Hello, I am asking you to move forward on several issues. First this oscilloscope did not start at all. I found the failure by dismounting the main acquisition board which had a capacitor on the burnt-out, short-cuircuit -12v. Now power supply OK, it starts. All voltages controlled. Good! Of course on 2nd failure, the disc is completely mechanically out of order. To be see later so disconnected at this time. Now on the outside screen, i have the bios and its errors. I have the impression that the retro lighting does not work (in theory powered by 12v and give HT.) LCD screen black. I don’t think there is a feature that starts the retro backlight later. Can you confirm that it simply starts basicly when power on. As, there is no keyboard, I wanted to plug one.It ’s a 5-pin din on an Atlas 757 PCI3 board. So I adapted the cable of a PS2 keyboard (cut + welded a din). It initializes (flash of the 3 leds at power on) but after impossible to communicate. So is the keyboard accounting AT or XT, it’s not the same protocol ? Somebody have made the test? So for that i am blocked for the bios Thanks for your answers cdt
Розпочато Gerard @ · Останніх @
Calibrating an early HP 53132A 7
For Christmas this year, I gave myself one of those cheap (~$100) Chinese 10 MHz disciplined oscillators. I've been needing something like this for about 20 years, ever since the state shut down the standards lab on campus. My best counter is an HP 53132A, which hasn't been calibrated in maybe 30 years, so, with the new GPSDO in hand, I set out to check its internal clock. This 53132 has options 10 & 30 (high stability oscillator and 3 GHz channel 3) so I was hoping that its clock had not drifted much, and I was pleased to see that the 10 MHz GPSDO signal measures about 0.200 Hz low, meaning that the internal clock has drifted only about 0.200 Hz high in 30 years. When I got out the manual I bought years ago, I discovered that my model, serial prefix 3404, was earlier than the manual I have, and it appears that the calibration technique is completely different. Serial prefix 3404 and earlier do not have the "automatic" frequency calibration that later ones do. For my version, I'm guessing that I'll need to tweak something manually. I've looked in vain for an earlier manual, but haven't found one so far. The most obvious thing to tweak is a hole in the rear panel labeled "Osc. Adjust." The only problem with that is that this hole and label also appears on later models with the automatic calibration firmware that I've watched on YouTube. I don't want to start adjusting it, only to discover that it adjusts something completely different. Is this the right place to adjust on early 53132s? If not, where should I look, or should I be happy with the 0.200 Hz error? And, BTW, anyone know what the H01 sticker means? thanks, -- Jim Adney Madison, WI USA
Розпочато Jim Adney @ · Останніх @
How to remove the CRT shield from an HP 140A mainframe? 3
I want to service the FP style electrolytics in my HP 140A oscilloscope mainframe. How do I remove the CRT shield, so that I can gain access? It looks like maybe the shield separates into two parts if I remove the brackets holding the trace rotation coil in place. Maybe the rear of the shield can then pass through the front ring? That would be enough to get access to the power supply electrolytics. Best regards, -Steve
Розпочато Steve Byan @ · Останніх @
Conductive 3D printing
Hello Folks, sorry for being a bit dim - if I remember correctly, one or two of you wanted to experiment with conductive 3D printing some time ago. I finally finished the promised video which looks at conductive 3D printing with common FDM printers. If you want to, the video is at https://www.youtube.com/watch?v=JnWH5Ziqyhk and no, you wont be able to print a PCB with it. Cordially yours, and all the best for 2025 Tam -- With best regards Tam HANNA Enjoy electronics? Join 21k4 other followers by visiting the Crazy Electronics Lab at https://www.instagram.com/tam.hanna/
Розпочато Tam Hanna @
Connecting High-Impedance Probes to the Sampling Oscilloscope HP 54750A 11
Hi all, I plan to measure high-voltage pulses using a sampling oscilloscope HP 54750A to take advantage of its high sampling rate and vertical resolution. To do this, I need to connect a high-voltage probe, such as the Tektronix P6015A or CT4028, to one channel of my 54751A. Unfortunately, there is no original adapter for such a connection. For the DCA series oscilloscopes, the N1022A or N1022B adapters are available, but these are only suitable for active probes. After a quick search: High-impedance buffers for converting from 1 MΩ to 50 Ω are available from Agilent: E2697A Tektronix: TCA-1MEG LeCroy: AP-1M Based on the operating manual, the TCA-1MEG seems suitable for use with the P6015A, but it contains some internal black box that may require specific settings to function. The Agilent and LeCroy options might also work, but I couldn't find their derating curves or confirm whether they require additional configuration. My question is: Does anyone have experience with these high-impedance buffers? Do they work directly when powered, or do they require specific settings? Can you recommend any other solution for this setup? Matt
Розпочато MatejBA @ · Останніх @
Fixing dim displays on the HP 8753ES VNA
I have had dim displays on a number of units that I have had over the years either from our lab at work or units that I have purchased to repair/resell. In most cases, they can be fixed for $0.25 using a little piece of aluminum foil. Here is a video where I go through the process in case anyone has this issue. The 8753E display is similar, but much harder to disassemble (more screws, some tabs to bend, harder to remove the CCFL lamp). https://youtu.be/k_W8FeLfxBQ Happy Holidays to one and all!
Розпочато Scott Vance @
Inaccurate HP attenuator pads 3
In a 33321-60058 programmable attenuator (used in E4445), the 20dB stage is measuring 19.2dB attenuation on the VNA. This is starting to make the attenuation tests in the spectrum analyser a bit "touch and go". The manual suggests that a fail means 1dB discrepancy; but there's no detail on how exactly this is measured. The chip seems to be 1GT1-3237 and I cannot seem to find online any data for the precision or stabiliy of the attenuation. I'd have expected excessive input power would have increased the attenuation rather than reduced it (as in other burnt out attenuators I have known failed open circuit). Are replacements findable or is it a case of canabalise another damaged attenuator? Alan
Розпочато Alan Bain @ · Останніх @
Opinions on the 82357B vs NI USB to GPIB adapters? 20
Use Agilent 82357B adapters are similar in price to brand new NI devices. I'd prefer to use Agilent/HP generally, but also seem to recall reading that the Agilent devices are troublesome. Is that correct? What do folks recommend? James W7TXT
Розпочато James Morris (W7TXT) @ · Останніх @
HP 6645A Fan Noise 14
I purchased this HP6645A power supply from Radu Dicher about a month ago and have been a bit slow getting it set up for use due to my other obligations. It's exactly as advertised, appears to work just fine, and I even added banana jacks in the rack mounting holes (which I'm not otherwise using) so I can use standard test leads with it. Looks like a really sweet unit. My only issue is fan noise - not horrible, but a little annoying for continuous use. Has anyone else replaced an HP 6645A fan with some quieter type? Steve Hendrix
Розпочато Steve Hendrix @ · Останніх @
E4925A LCR Meter self test failed, cal error 5
Hi all, I'm wondering if anyone can help me with troubleshooting/service information for this LCR meter. I don't see it in the Wiki list, and can't seem to find much of anything about it in web searches either. It has worked well for several years, but today it flashed some error message during the boot self-test, and the displays went blank. Certain functions like the calibrate will still respond, but with error messages like this one. I have no documentation for it. I bought it on ebay from a liquidator and happened to know basic operation because we have the same model at work. Any ideas where I can get a service manual or schematic? Or even the operating manual? Maybe I can find documentation for the one at work, but I wasn't expecting to be in the office for several days. Thanks Jeffrey
Розпочато Jeffrey Ludlow @ · Останніх @
HP 8643A Repairs, 2Units, PS and VCO 3
I was going to make a youtube video about this and I wrote up the notes below but it is easier to just post the notes. I am new here, retired EE in March of 23. I am 71 years old. Most of my career in the computer and storage industries but have always been into RF. Anyway, I got these two 8643a units off of Ebay for about 250 each shipped. Neither was working but they are both running now. The information available in these units is relatively sketchy compared to most instruments I have worked on but fortunately there is a schematic and some block diagrams that allow one to make some inroads. Here are the notes: 1. introduce myself 2. History of units a) purchased on ebay or ~250 each b) unit A condition unknown as it would not power up. Dirty and dented, Output connector bent. c) Unit B is a 2ghz unit (option 2) and fails self test. Hardware err 2 and 14,03nn,nnn. 3. Justification for buying 2 was making one good out of two. 4. I have no experience with this units. Unit A 1. Unit A arrived first in the mail. I tried to power it up and it came on! But only once. 2. I watched youtube videos about power supply repairs and ordered Artek documentation. 3. When the schematics arrived I realized that the 24 volt supply was needed in order to power the unit up. 4. I removed the 24 volt supply. I then removed the 3 large output capacitors but testing showed them to be OK. I tried to remove the small 22uf capacitor but one leg stayed in the board so I replaced it with a 47uf from my junk box. 5. Voila! The unit now works and passes it's self test. Looked at output on the spectrum analyzer and it looks good too. 6. I did some cleaning and put it all back together. I straightened the crooked output connector. 7. Thanks to the fellow who made the youtube video about recapping and was kind enough to post a list of capacitors. I used the list to make an order from Mouser with caps for both units. Unit B 1. When this unit arrived and was failing, I immediately went after the power supplies. I removed them from the unit and tested them on the bench. But even under load I could find no issue so I put them back and ran diagnostics. There were no power supply failures but the hardware error 2 indicates a VCO problem (Owners manual table 7-2 on page 7-11, Artek page 217). Here I went on a lengthy sidetrack because I looked at the signal on VCO J1 with my spectrum analyzer and saw a good strong signal up around 0dbm at a frequency near 880MHz. It would jump up a few MHz every so often and then back down. I looked at my good unit and the signal was a little stronger but 100Mhz lower so I figured something was messed up at the input to the VCO. 8 hours later I got back to the amplitude issue. 2. Running the self test gave +2,100,116 indicating a bad STD VCO. I reset the instrument, cleared all messages and ran the test again. This time it led me to do test 4A on STD-VCO J1 and then failed. This test just connects J1 to the built in power meter. 3. So, what is the expected output power on J1 and what was the actual? Running test 182 with J1 connected to the power meter input gave a reading of 2.2dbm. 4. On the block diagram of the STD-VCO in the Service Manual it shows J3 to be at +3 to +10dbm so the output is low. 5. Looking at the schematic I saw U501 in the VCO with an HP part number of HPMA-0406. It looked like a buffer amplifier. 6. I disconnected all of the coax/hardline connections but left the ribbon cable in place. The CLIP showed U501 inside the small metal box on the VCO board. I removed the covers and the small box and then, with the bottom cover plate in place I laid the VCO on top of the generator so that I could access U501. I used by Boonton 92BD to measure the RF in and out of U501. 4xx millivolts in and 2xx millivolts out. 7. I did a search on the web and found an MSA-0486 on ebay in the same SOT-86 package with the same A04 marking. It is a MMIC amplifier DC-3.2GHz 8.3db gain at 100MHz 8db at 1GHz They were cheap so I ordered 4 of them from a US supplier in PA. 8. When they arrived, I replaced the amplifier. I used a hot air
Розпочато mux_folder2001 @ · Останніх @
HP8505‘s sets for sale
Dear All, I need some space in my lab. I am considering to sell my two HP8505 VNA‘s. I have two units , both working. One unit has homemade interconnects and the display / tube has low brightness but is still usable. The second unit has good brightness and the original interconnects. both units come with the storage normalizer and the 50ohm S-parameter test set each. Complete set of original service manuals with all schematics. In addition I have one source and two display units non-working and incomplete for spare parts. A HP5004 signature analyzer is available as well. The designed precision of the VNA without further corrections was always impressive …. But I need the space. Maybe it is already a collectible, I guess it was HP’s first CPU-controlled VNA. (?) Units are located in western part of Germany. Because of the weight for pickup only. Only the whole set, I not selling single items. if interested, please make a offer, I will not give them away for free, so please be reasonable if seriously interested. best regards, Olaf
Розпочато DL8EBL @
3577A update 3
The problem in the fast processor seemed extremely difficult to nail down so I figured I'd fix the other main problem, the two bad SRAM chips in the trace memory. The parts arrived early this evening and I installed them. Fired up the unit and figured I'd quickly try to run the trace memory test before the unit quit. Memory passed. But, the weird thing is that the instrument did not stop or show any errors like an unlock. It appears that bad chips in the trace memory can cause a false indication of other errors in completely different assemblies. So if you do have bad chips there and other issues, I highly recommend that you fix the trace memory before looking at the other errors. Peter
Розпочато Peter Gottlieb @ · Останніх @
Perpetual licence fees - what's the best option? 16
I'm considering purchasing a new VNA, which is a pretty hefty outlay. However, i'm amazed also at the high annual costs of the node-locked perpetual licences. Apparently, these also cover software support. Is there any way of getting around these costs so i can continue to operate without spending a huge amount on the annual licence fee? I'm perhaps not so interested in the online support, once you're familiar with the kit, you can manage without this. I don’t have to pay anything for my old VNA you just connect up and start working. many thanks for any advice, Neil
Розпочато neil @ · Останніх @
HP6624A Power Supply - screws on the terminal strips - what size? 10
Hello Group - I got this 6624 quad power supply. All the screws in the four terminal strips were removed. M3 is too small, M4 is too big. 6-32 is about the right diameter but wrong thread. Anyone know what size these things are? (reminds me about a thousand years ago Acopian used some oddball (but Imperial) screws, like 3-32 or 5-32, something like that. Thanks in advance. Dan
Розпочато dan.meeks222@gmail.com @ · Останніх @
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