HP 5335A and HP 5370B Universal Time Interval Counter

[@davidv1289]

Two really nice HP counters! Thank you for showing them to us. A couple of tips for the 5335A - first, get Service Note 5335A-26B and check out your power supply relay and socket, there is a problem with overheating that may damage the relay, socket and board. Second, there is a firmware revision available, during boot-up check to see if there is a decimal point between "ADDRS" and the GPIB address number. If not, then firmware revision 1.0 is installed and can be upgraded to version 1.1. But be careful, there are two different versions of 1.1 depending on which channel C prescaler is installed. I adapted AT28C64 EEPROMS to replace the original PROMS. Lastly, if you would like MORE resolution, replace A4C36 with a 22 uf to 47 uf 10 volt low leakage capacitor (value is circuitry tolerance dependent - I used a 22 uf in mine - tantalums are okay). This extends the gate time to a maximum of about 12.5 seconds. Connect a 10 MHz (or just over) source and check the display with the gate time set above 10 seconds. Regards, David

[@CraigPetersen12f36b]

Thanks for the tips David, I carefully inspected the unit off camera and didn't see anything obvious. The counter I show in the video has firmware version 1.1, it also has the channel C board installed. The other 5335A I have came with only option 40 installed, I added option 010 about 8 months ago, this unit also has firmware 1.1. I'll download the service notes and check for this issue during my next service interval. Once again thanks for the tip and thanks for taking the time to watch the video.

[@VintageElectronicsGeek]

What a lovely pair of lady's! I'd like to add one to my collection as well one day, but like you...I have no more room! But that wont stop me from buying and storing! :) I'm testing a HP 140T SA right now with the option to buy, not sure of $$$ But I will offer a C note for it, they're great for finding a signal but not a viable tool...cant tell you what freq your on but they do have swappable modules that go from hertz ~ 40GHz in four modules, so some value. Thanks for sharing! ~Jack, VEG

[@CraigPetersen12f36b]

Good Morning Jack, the old HP 140T is a pretty impressive old spectrum analyzer, I believe with the right plug-in you can get down to 10Hz of RBW. I have two HP 853A's and like the HP 140's there is no practical way to accurately measure the frequency of displayed trace. Depending on the plug-in the HP 853A's center frequency display is accurate only to 1MHz or so. A HP 5335A would make a great addition, you can always add options later if you cannot find a fully equipped unit.

[@_PJB_]

"You can't have enough test equipment". Would you mind explaining that to my wife? :)

[@markgreco1962]

With patience you can find anything. I’m looking for a HP 59304a digital display been 2 years now.

[@CraigPetersen12f36b]

Good Morning Mark, that and the clock are other units I'm looking for myself.

[@markgreco1962]

@@CraigPetersen12f36b just saw a clock go for 100$ needed work. Love the HP equipment