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Serious question here because I think I don't totally understand. Why do you need the notch filter if you can just see the harmonics on your scope and ignore the fundamental?

Very interesting video. My HP 8595E doesn't work properly. I can see a problem with PSU. Your documentation would be very helpful for me. Could you help me, please? Mark

I actually really enjoyed the time-lapse sequence, you might consider doing that more.

Thank you for cutting the connector instead of the board...you had me scared there for a minute.

Yes it's a 68000. The 3585A used the same processor as the 9825 computer- a hybrid 16-bit CPU made in NMOS which was based on the instruction set of the HP 2100 minicomputer.

The 3585A apparently has an HP "Nanoprocessor" on one of its cards. This was an odd little 8-bit processor designed for control applications, which was made using metal gate transistors back when just about every one else was using superior silicon gates, and had a die bias voltage which varied per chip (it was written by hand on the ceramic package after testing and packaging). It had no ALU but it didn't really need one, and it was very fast.

Well that was a heart warming and entertaining series. I want to see your father's cabinet for it.

Hi! I just found your video while looking for information on my grandpa's old oscilloscope, which is the same model as the one here. Do you happen to know the dimensions of the fuse installed on the rear panel? The operating manual I found online specifies its current rating but not its physical dimensions. Thanks!

Operators manual assets.fluke.com/manuals/93_95_97umeng0000.pdf

Awesome videos on this unit

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Could you possibly pull the fuse cap out and send me a photo? Or direct me in the direction of which one I should order? I believe mine is a Schurter, and I have ordered (2) different styles, but neither are the right ones. I really don't want to have to tear it all apart just to replace the fuse holder. If you could send me photo or video, or tell me what fuse cap I should order, I would be thrilled!

I believe the reason the steel springs in the front panel button mechanisms break or dislodge and have excessive “snap” is because of accumulated dirt in the area where the spring and plastic contact one another. I used Deoxit F5 spray for faders and pots to restore consistent feel and lighten the snap action of the buttons, without disassembling the unit. Examining your video, I can see that spraying into the gap at the upper third of the right side of each key cap will direct the cleaner/lubricant into the spring assembly. A small shot of F5 was enough to clean and lightly lube the contact surfaces. Be sure to use F5, as D5 lacks the needed lubricant to restore the feel of the key action. Should prevent future damage to the keys.

Great video! I recently picked up one of these with only the HPIB interface option equipped. I ordered a 10811-60111 oscillator from ebay to upgrade from the TCXO. Mine has the add-on LED in the bottom left corner of the front panel, as a few of yours do. I know there is an OVN annunciator on the right of the LED display. This extra LED illuminates whenever AC power is connected to the unit. Does this LED mirror the OVN annunciator, or does it just verify power is applied to the oven when in standby?

Excellent work - very well built! Not sure about the HP 334A but the HP 333A has an output from the filter that can be connected to your spectrum analyzer to extend the dynamic range. You might keep an eye out for an HP 3562A Dymanic Signal Analyzer - if you really want to go further down that rabbit hole. Regards, David

I’m a big fan of the ESP website. I’ve spent quite a bit of time reading the articles there. Thanks for the info on the the other topologies, I will have to look into them some more. This twin tee only goes to 20Khz but I’d really like to extend that range to 200khz. I think that is possible using a SVF, not sure about twin tee though.

Nice internal construction. I like the logical layout and separation……resulting in its good functionality.

What would you estimate the availability of parts and the total your cost not counting time? Very nice video! Had to sub.

Well-done! And thanks a million. I've seen this photoresistor calibration described in forum posts, but never seen it done. Fiddly, but not nearly as bad as I'd feared, should I ever need to work through it. My 334A works fantastically with auto-nulling, but the main dial doesn't read out/ "see" the correct frequency, and slipping the dial won't correct for the discrepancy. Not a huge problem, as one can always use a frequency counter (and most of the time, the input frequency being used is known anyway).

Excellent repair job !

In my recollection, another big difference between the 334A and the 333A was the auto-null. It is selected by the prominent switch to the right of the meter. You could start with Manual tuning and then turn to Auto for the final null finding. For years, I was drooling for this 334A. In our Ham & HiFi club, we had two Heathkit analyzers for our audio endeavors, one was harmonic distortion analyzer and the second one for intermodulation (2-frequency) analyzer. This HP 334A (and the 333A for that matter) was way more expensive than both the Heathkits, and still missing the intermodulation feature. So, keep drooling, guys!

I built an AA-15 in ‘71 (when I was 18) and an AJ-15 tuner in ‘72. They were awesome. I made the mistake of lending them to my sister and after a short time they were stolen. But they were awesome while they had them.

I got dizzy from camera movement

Mr Free Electron is using his time, physical energy and personal finance to make some valuable videos. May I suggest that he opens a Paypal account so that subscribers could make financial contribution thus alleviating in some measure his financial expenditure. It could be a sort of Win-Win situation.

Thanks for your great series on HP spectrum analyzers. I have noticed that your HP8595E has options 101 and 105 I hope that one day you will make a video on the use of Time Gated Spectrum Analysis.

Many thanks for your document , I wish you the best to you and your family happy Christmas ON1EV

Thanks! I was given a 97 today to replace mine that has an error after 30 seconds. The "new" one had no backlight. Replaced that cap and it has a beautiful backlight now. That transistor was getting hot like you showed.

I have made my notes available from this video. Check the link under the "more" option.

Excellent video. No doubt it will be of great help to technicians who need to repair their analyzer. Thanks.

Hi, your work is so valuable, I am in the same position I want to repair this PS, it is used in an HP 8591A CATV spectrum Analyzer, could it be possible to download the so valuable document you have done , here in Belgium there is still an Hamspirit and I want to help my Friend ON4LAU to repair its power supply. Best regards ON1EV

Thank you for the useful information! I have one exactly equal to the one you showed on my bench, and I’m just startiing to face the challenge. I woul like very much to have access to all this information you collected. In case you decide not to post it please let me know if there is any other way to have acess to it.

I want to purchase a complete mantenance manual, how mutch is the cost ?

can I print all the squematic circuits?

Good Job finding the bad cable. Your unit seems to be working within specifications. The actual specification sheet I have looked at Sets the calibrated output flatness of 2 db at frequencies above 10 MHz 9kHz is a test but does not seem to be defined as a specification.

The 600 ohms mentioned on the meter low side print is only there for defining what dB reference they are talking about. There are several more or less "standard" references in use. You can use something defined at 50 ohms, for example. It just uses the power at resistance rather than direct volts or millivolts, for example. The meter input resistance is 10 Meg, if I remember. The only effect the terminator (attenuator) would be to match the output (i.e. input to the 3400) to the signal source, in case it expects a 50 ohm load, and you want to use the generator meter as your reference.

Marvelous video. Is there an hp part number for the IF test board? Would you think it may be reproduced?

Most of the information is available from the 8590 series service manual. That’s where the cal attenuator, frequency correction constants and IF adjustments are from. I believe the service guide is on the web but you’ll have to find it.

Is the procedure document shown in prior video available or posted? Great series, thanks!

From W1°23'42.43" · N42°34'33.13" Great job. Just two people, is amazing!

Time to calibrate your generator. Thanks for this valuable reference!

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Thank you for posting this! I have an 8593E and fortunately wrote down all the calibration data the minute I got it, but you never know.... I may go through the adjustments at some point just to check how much it has drifted over the years. IF I can find the tools needed.... I am on the lookout.

The electrolytic capacitors did not dry out. The simply needed to have been reformed.

As for the PSU: I recommend replacing the three yellowish RIFA XY caps that are hiding under the power input. These things have the nasty habit to deteriorate over time, get cracks in the plastic and when the time has come explode/catch fire and whatnot. In a pinch, the PSU runs without (don't ask me how I know, I need to order caps that physically fit, it is a tight fit there).

As far as I know, the battery on these things can't be checked beforehand. Chemically, they hold the wanted voltage and that voltage never goes down but they will go completely flatline once they are tired. After 10+ years, I recommend switching them out

Thanks for the information. I would really appreciate if you could post your documentation, I remember I was trying to repair one one myself but haven't gotten anywhere.

Excellent video and insights. No disrespect, as I know next to nothing... but I believe you may want to use the word Characterize instead of Categorize. Please let me know if I'm off base. Cheers and thumbs up! char·ac·ter·ize /ˈker(ə)ktəˌrīz/ verb 1. (of a feature or quality) be typical or characteristic of. "the disease is characterized by weakening of the immune system" 2. describe the distinctive nature or features of. "the historian characterized the period as the decade of revolution"

Please, I need a good phone number or email to reach the HP repair center for the 8951A HP spectrum analyzer

Hello, nice video. About midway thru you showed a block diagram and mentioned there were schematics available? Would love the link if you don’t mind. Thanks.