HP 35665A service guide  - Page 1
Forum section: electronics / testgear

author: mightyohm
author_rank: Regular Contributor
timestamp: July 17, 2021, 06:56:15 pm
content: I thought that the common knowledge was that this service manual didn't exist (or maybe it's just the pdf that doesn't exist) but one just sold on eBay:https://www.ebay.com/itm/334079742743Maybe we can convince the buyer to scan it.Has anyone been able to locate a pdf?

author: Peter_O
author_rank: Frequent Contributor
timestamp: April 02, 2022, 08:02:43 pm
content: Quote from: mightyohm on July 17, 2021, 06:56:15 pmPulling this thread up from history:I'm searching for the "HP 35665A Service Guide" too. It's referenced e.g. in the concept guide with this string exactly.There is an HP 35665A Memory Upgrade Installation Procedure:https://www.glkinst.com/test-equipment/manuals/35665-90060.pdfAnd a service guide of the somewhat similar 35670A:https://www.keysight.com/de/de/assets/9018-01341/service-manuals/9018-01341.pdf

author: Louiebluey
author_rank: Contributor
timestamp: April 02, 2022, 11:29:01 pm
content: HP 35665A-90031 service guide on Google Drivehttps://drive.google.com/file/d/1foUXt5DUGoiw3OGIxmDoXEJ-oenD2k0c/view?usp=sharing

author: Tomorokoshi
author_rank: Super Contributor
timestamp: April 03, 2022, 04:11:01 am
content: Quote from: Louiebluey on April 02, 2022, 11:29:01 pmGreat! Super! Wonderful! Terrific! Awesome first post!

author: Peter_O
author_rank: Frequent Contributor
timestamp: April 03, 2022, 04:51:12 pm
content: Quote from: Louiebluey on April 02, 2022, 11:29:01 pmYes, this entry post is absolutely incredible indeed.Thank's a lot and more, Louiebluey!You've just made some TEA guys very happy.Do you see or does anybody see any problems with legals etc. when we think about uploading this valuable paper to a standard community repository:http://ftb.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent/HP_35665A_Dynamic_Signal_Analyzer?

author: Tomorokoshi
author_rank: Super Contributor
timestamp: April 03, 2022, 06:16:45 pm
content: Quote from: Peter_O on April 03, 2022, 04:51:12 pmFortunately, Keysight seems to be endorsing accessibility to copies of manuals for old equipment:https://edadocs.software.keysight.com/kkbopen/where-can-i-find-manuals-for-discontinued-keysight-agilent-and-hewlett-packard-test-equipment-577941709.html

author: Louiebluey
author_rank: Contributor
timestamp: April 03, 2022, 07:26:26 pm
content: Feel free to share or post the manual anywhere.

author: Louiebluey
author_rank: Contributor
timestamp: April 03, 2022, 10:28:33 pm
content: Turns out I can clone LIF formatted disks of the Performance Test Disk (ITM_35665A) using the machine itself. So, if anyone wants one, it's cost to mail a floppy with some cardboard I guess; no idea what that costs these days. This is the disk needed to run the procedures of the Service manual.Or, I can clone one and maybe someone else could take over cloning from there?I have an 8MB machine and formatted the RAM: drive to something like 3 MB, then it worked for copy all files. (format new floppy in LIF, copy master disk to RAM:, then copy RAM: to INT:, the newly cloned disk formatted in LIF.Maybe someone knows how to image an LIF formatted floppy?

author: Peter_O
author_rank: Frequent Contributor
timestamp: April 04, 2022, 11:33:52 am
content: Quote from: Louiebluey on April 03, 2022, 07:26:26 pmThanks!Just have uploaded it to KO4BB. Will take some time to be listed.

author: Peter_O
author_rank: Frequent Contributor
timestamp: April 04, 2022, 11:37:12 am
content: Quote from: Louiebluey on April 03, 2022, 10:28:33 pmTested the floppy drive yesterday and tried to format a HD floppy, with and without the DD hole closed.The drive made usual noises but came up with an error: wrong or bad disk.This for both: DOS and LIF formatting.Any hints?

author: Louiebluey
author_rank: Contributor
timestamp: April 04, 2022, 06:34:42 pm
content: The service guide shows how to remove the floppy drive. If you are lucky, maybe it is just a matter of carefully cleaning out any debris inside the drive. There might be an electrolytic to replace too (should be clearly visible once the drive is opened to expose the board). There are a lot of YouTube videos of people refurbishing floppy drives. Our floppy drive part is SMD-340 (in the manual, bottom of page 7-6). No idea if the more common SMD-1340 is a direct replacement, there are probably other replacements too, possibly a similar Teac from the time. They seem to run $20 to $50 refurbished.Or, you could look for some other broken gear from the era that has the same drive too, but you might end up needing to refurbish it too.There are USB floppy emulators, but reading here and elsewhere, it is a bit of a gamble, and involves at least modding the common emulator boards, possibly more trouble than its worth.

author: Stray Electron
author_rank: Super Contributor
timestamp: April 04, 2022, 07:30:46 pm
content: I've never looked at the floppy dive in a 35665 but I've worked on a bunch of the old HP-IB interfaced floppy drives and I can tell you that the grease on them dries up and hardens and won't let the drive open fully and the top head will scrape across the magnetic disk and WILL ruin it. And it will frequently damage or destroy the gimbal on the top head and ruin the drive as well. Use an expendable scratch disk to test the drive and not your HP disk. Make SURE that the drive opens fully before you try to remove the disk.Also open the shutter on your disk, rotate the media and check both sides for damage.If i were you, I would remove the drive from the 35665 and check it closely and I would probably go ahead and clean the old grease off and re-grease it will a good quality grease that will not dry out.Do NOT ask me how many drives and irreplaceable disks I ruined before I figured this out!

author: Peter_O
author_rank: Frequent Contributor
timestamp: April 05, 2022, 08:41:24 pm
content: Thx to you both, appreciated!I took an empty HD disk I found in my 'IT-museum'. It rotates fine and has no scratches on any surface from the tests inside the 35665. The floppy does make 'nomal' noises and seems to rotate. Entering and releasing the floppy works fine too. Feels like any PC in the 90s.Anyhow. I take you advice and will put the drive restoration on my action backlog.For now I ordered a new battery today, some eproms and a programmer to give the options-adding a try.

author: Peter_O
author_rank: Frequent Contributor
timestamp: May 21, 2022, 09:17:51 am
content: Quote from: Peter_O on April 03, 2022, 04:51:12 pmMeanwhile, the upload to ko4bb has been relocated to it's final position with the other 35665 documents:http://ftb.ko4bb.com/getsimple/index.php?id=download&file=HP_Agilent/HP_35665A_Dynamic_Signal_Analyzer/HP_35665A_Dynamic_Signal_Analyzer_Service_Manual.pdf

author: andymok
author_rank: Contributor
timestamp: May 26, 2022, 04:49:49 pm
content: omg I love you so much!

author: andymok
author_rank: Contributor
timestamp: June 01, 2022, 03:05:42 pm
content: Thanks to the service manual, i was able to locate the faulty +10dB diff amp that causes dc offset, heating up compnents downstream.Now I'm trying to follow the manual and adjust the machine. In page 5-8 "3.ADC Gain, Offset and Reference", it mentions a Capatitive Load for oscilloscope probe. Any clues what could the capacitance be?Much appreciated.

author: Peter_O
author_rank: Frequent Contributor
timestamp: June 01, 2022, 07:04:19 pm
content: The table 1-4 on page 1-6 lists the capacitive load HP 35660-64401.Searching the web shows, that in the paper for the portable sibling:"Agilent 35670A Installation & Verification Guide",e.g.http://ridl.cfd.rit.edu/products/manuals/Agilent/signal%20analyzer/InstallationGuide.pdfon page 1-20 it says:"Capacitive Load Value: 3300 pF HP 35660-64401".So it might just be a 3.3 nF cap. At your own risk.