Author Topic: HP 3312A Frequency Drifting Downward  (Read 396 times)

0 Members and 1 Guest are viewing this topic.

Offline SipolandisTopic starter

  • Newbie
  • Posts: 2
  • Country: us
HP 3312A Frequency Drifting Downward
« on: December 28, 2024, 03:53:42 am »
I acquired an HP 3312A Function Generator that works in all regards, except that the output frequency drifts downward about 100 Hz/second. Any pointers to the likely culprit?
 

Offline Swake

  • Frequent Contributor
  • **
  • Posts: 718
  • Country: be
Re: HP 3312A Frequency Drifting Downward
« Reply #1 on: December 28, 2024, 09:58:22 am »
As always start with checking out the power supplies thoroughly.
You could also post the schematic to make it little easier helping you.
When it fits stop using the hammer
 
The following users thanked this post: Sipolandis

Offline Wallace Gasiewicz

  • Super Contributor
  • ***
  • Posts: 1379
  • Country: us
Re: HP 3312A Frequency Drifting Downward
« Reply #2 on: December 28, 2024, 03:03:28 pm »
The 3312 frequency is determined by Resistance Capacitance circuits. There is no crystal reference.   
Any of the controls including the front panel potentiometers are suspect.  DIRT can cause this, so cleaning is a good first step.     
If you can leave it powered up for several hours safely, that may help also.       
Search for HP 3312 in the entire forum, there are numerous posts.   
Artek has good manuals for this unit, search for 3312           

http://artekmanuals.com/manuals/hp-manuals/
« Last Edit: December 28, 2024, 03:33:56 pm by Wallace Gasiewicz »
 
The following users thanked this post: Sipolandis

Offline Manolo Mos

  • Contributor
  • Posts: 22
  • Country: es
Re: HP 3312A Frequency Drifting Downward
« Reply #3 on: December 28, 2024, 05:05:01 pm »
I have this HP too. This defect is normal, is due to a mediocre design. The exact place of the component that provokes this drift in the small printed circuit, below, it was a metalic 8 pin circuit integrated. I don't remember which was. I'd don't use these instrument for frecuency precision works, it's clear it is don't made for this. Mine is keeped in a shelf, maybe someday goes to the electronic waste facility dump.
 
The following users thanked this post: Sipolandis

Offline SipolandisTopic starter

  • Newbie
  • Posts: 2
  • Country: us
Re: HP 3312A Frequency Drifting Downward
« Reply #4 on: January 02, 2025, 09:25:27 pm »
It's curious that this would be standard behavior for any HP gear. I have a couple of old vacuum tube signal generators that are rock solid. My best guesses are a capacitor that is drifting, or a thermally unstable transistor or IC.  I can leave it on for several hours and it keeps drifting downward.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf