HP 8593A spectrum analyzer demodulator speaker and battery question - Page 1
Forum section: electronics / testgear

author: emptech
author_rank: Regular Contributor
timestamp: November 05, 2017, 03:35:25 am
content: I just purchased an HP 8593A spectrum analyzer, which seems to work just fine. I noticed that it has a volume control on the front panel. I see where there can be an option 102, which provides an AM/FM demodulator with speaker. The documentation says the option could be purchased extra. I have not taken the cover off to see what is actually under the speaker grill, so I don't know if it is missing the hardware or if it can be brainwashed. Does anybody know if I have any options here? It's not something that I absolutely have to have, but it would be nice to have sometimes.While I'm at it, I see the battery for memory and calibration settings is seven years old, I presume it takes some kind of coin cell? When replacing the battery, do I have to apply an external DC voltage to maintain the memory settings when the cells are swapped out?I tried some searches, all I could find is mention of the speaker in various operator's manuals.Jim H.

author: MarkL
author_rank: Unknown
timestamp: November 05, 2017, 08:56:47 pm
content: It's rare to see the AM/FM demod option obtainable by itself. Usually you have to find a parts donor. I found one passing reference that says the part number is 5062-6457. You could also use the quasi-peak option 103 retrofit kit 11946-60003, which also does demodulation.Both involve a card that plugs into the expansion backplane. If you don't have the speaker, you probably don't have the card. So, it's not as simple as wiring up a speaker if that's what you were thinking.On the battery, I couldn't find a 8593A service manual to answer your question definitively, but the A series does share a lot in common with the E series. The assembly level service manual for the E series may be of some help:http://www.keysight.com/upload/cmc_upload/All/08590-90316.pdfBefore you try doing anything with the battery, you should backup your calibration constants. Try the procedure found in the above manual to see if it's applicable to your A series.The battery is probably an AA size lithium (TL-5104) mounted near the back panel. It's also possible it's a larger coin cell (CR-2477) mounted on a daughter card which holds the memory expansion, if it's more like the E series.Pop the case open and post some photos so we can see.If you're interested, there's a quasi-peak 11946-60001 retrofit kit on ebay right now for a ridiculous price, item 292317854383 $295 (but has Make Offer). It will work in your 8593A according to the discussion and installation manual here:https://community.keysight.com/thread/23237

author: emptech
author_rank: Regular Contributor
timestamp: November 07, 2017, 09:09:23 pm
content: Thank you for the reply. I read that there was an option to purchase the option, but I'm sure that was many years ago. I haven't opened up the cover yet, my guess, there is no speaker there. I also read that when the machine powers up, there would be a beep, which there isn't.I will follow the instructions on backing up the calibration data, no sense in making more work for myself. From the E series manual, there appears to be a 3.3volt 1Ah lithium cell with wire leads. Following links, it appears that current cells by the recommended part number do not have leads and go into a holder. If the replacement needs leads, I'm sure I can find somebody to weld some tabs onto a new battery, I know that soldering to a cell is generally a no-no, although I've actually done it many times, using the proper soldering flux, solder, and a very hot iron to get the process over quickly.On an old spectrum analyzer, I recall using the chart output going to a speaker would actually play the sounds, not all that important, just wondering how difficult it would be to get the speaker to work, I'm sure it isn't worth the trouble.Jim H.

author: MarkL
author_rank: Unknown
timestamp: November 08, 2017, 12:14:30 am
content: Quote from: emptech on November 07, 2017, 09:09:23 pmIt appears in the 1991 catalog and the 102 option was $1500. This unit and its brethren have been obsolete for a long time.QuoteGood luck on the backup; post a note so we can all know if the E instructions work for an 91/93A series.I haven't seen inside an A series, but I know the E series have soldered in batteries. In the E series, there were two types of batteries that were used depending on the age of the unit. I'm guessing you'll find one of the two in your A unit.And yes, you're correct, don't solder to the battery. If it's anything like the E series, the direct replacement for the Tadiran AA cell with axial leads is TL5104/P. If it's a large coin cell it should be the Panasonic CR2477/HFN, which has solder tabs. You can find them at Mouser, Digikey, etc. I would stay away from ebay and other dubious sources since you don't know how long they've been sitting around.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: November 08, 2017, 09:56:38 am
content: All of my 8591 spec ans have the demod in and I do not remember ordering it as an option. I did order a lot of options, they all have tracking generators and two of them are full EMC spec which I would expect to come with the demod but not the others.It is pretty crap anyway unless you are thinking of feeding it to something else from the speaker output. It only gives output when the trace is not sweeping so listening to music through it is somewhat naff.