HP 5342A curiosity - Page 1
Forum section: electronics / testgear

author: pinpassion
author_rank: Contributor
timestamp: May 03, 2025, 09:00:51 pm
content: Hi gang,I picked up an HP 5342A Microwave Frequency Counter. From my very limited testing it appears to work properly. I did the self-check in the manual and got the 75 MHZ display as shown there. I then did the operator keyboard check in the manual and everything was exactly as shown. I then hooked up the frequency standard output on the back panel into the input #2 (10HZ - 520MHZ) front panel input and got exactly 10MHZ on the display.My unit, based on the serial number is prefix 2840A. I can't find a reference to that in any online manual for the 5342A. The manual I have is dated 2/1979. It covers serial prefix 1840A.My unit was purchased under government Army contract and has a top panel sticker with all the numbers associated with that contract. It also has a sticker indicating it was "Overhauled Tobyhanna Army Depot" with a date.There were no option stickers on the unit, but I was happy to see an option 001 hi stability oven installed when I removed the top cover. It's the 10811-60111 unit. Serial prefix 2332A.One thing I noticed compared to some U-tube videos I watched is my unit does not appear to have the key clicks when pushed. I think they called them west keys. They all work perfectly when pushed, just no click. Were the front panel keys updated at some point during production? I have seen issues whereby the metal strips that serve as springs fall out and cause trouble.So if there is anything known about prefix 2840A or the keyboard I appear to have, please let me know.Thanks,Mike

author: wkb
author_rank: Super Contributor
timestamp: May 03, 2025, 10:38:27 pm
content: The metal leaf springs of the Bill West keys tend to become sticky over time and that makes them click. So no click is good news.Or, alternatively, the springs are broken / have fallen out of the key assemblies. I doubt that all of them would suffer from that though.A visual inspection of the keys would be required to find out.I have 2 of these counters and had to clean the keys to fix the clicking.Wilko

author: KE5FX
author_rank: Super Contributor
timestamp: May 04, 2025, 02:43:45 am
content: Exactly; as counterintuitive as it seems, they aren't supposed to click.You can restore click-free operation byspraying some alcoholthrough the openings around each key switch. More or less magic.

author: wkb
author_rank: Super Contributor
timestamp: May 04, 2025, 08:02:12 am
content: This is what it looks like inside.

author: pinpassion
author_rank: Contributor
timestamp: May 04, 2025, 03:41:13 pm
content: Thanks Wilco for the images of the keys. I did get a look at them in the Utube videos I saw on the 5342A, but not as detailed as your pictures. I don't think those posters were aware the keys are not supposed to click. None of the keys on my unit click and they all work perfectly. Mine was "overhauled" by the Army base, so perhaps cleaning the keyboard was part of that process.I hope I can learn something about serial prefix 2840A. That would seem to represent some major change from the prefix 1840A that my manual covers. My unit also has the HPIB interface, and that apparently was an option as well. I'm not sure yet if the oven and HPIB are the only options installed. I did remove the top cover but I have not removed any internal covers. This unit is a beast and very well made. I understand it was very expensive at the time. To be honest, I think it is more counter than I will ever need. I don't have any equipment that even comes close to the 18GHZ top end, let alone the 24GHZ extension it can be upgraded to. For my needs it's a counter on steroids.Thanks for the help guys.Mike

author: wkb
author_rank: Super Contributor
timestamp: May 04, 2025, 04:37:00 pm
content: Be careful when you open the tin. The power supply of this beast has fangs...Both the OCXO as well as the HPIB were options. There are/were more options available, like RF power measurement. The manuals explain this quite well. Normally HP affixed a sticker to the rear of the unit stating any options installed.Mine have HPIB, OCXO, alas none of the other options.Wilko

author: wkb
author_rank: Super Contributor
timestamp: May 04, 2025, 04:39:35 pm
content: From the HP sales doc

author: wkb
author_rank: Super Contributor
timestamp: May 04, 2025, 05:00:52 pm
content: Upload problems.. hm?

author: wkb
author_rank: Super Contributor
timestamp: May 04, 2025, 05:11:49 pm
content: As for price of the counter and its options I found this in my stash of docs.