Got this unit for free recently, and decided to do a teardown. It is functional, but the buttons on the unit are absolutely terrible (hard to push, don't stay pushed, etc etc). Even after some contact cleaner - need to do a bit more work on that.
Click the image to embiggen.
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-1.jpg)
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-2.jpg)
The inside gets the "whole lot of nothing" award, presumably for the battery option:
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-3.jpg)
Power supply, note the internal voltage range switch:
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-4.jpg)
The actual counter is tucked behind the front panel:
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-5.jpg)
Removing the knobs (which had the set allen screws very stuck) shows the main board. Random note: the fat left 7-segment is inverted in order to put the "dot" next to the gate indicator on the front panel. A second LED is added for the Overflow indicator. The far right dot is used to indicate microseconds, and kilohertz just is indicator-less. Thats some creative cost cutting!
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-6.jpg)
I miss old package markings sometimes - a transistor:
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-7.jpg)
I can't find a datasheet on the main IC
![Sad :(](https://www.eevblog.com/forum/Smileys/default/sad.gif)
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-8.jpg)
The frequency reference / oscillator with the tuning adjustment.
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-9.jpg)
There are a number of these resistor packs throughout the board:
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-11.jpg)
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-12.jpg)
I'm also unsure of what to make of this fuse - looks like a cotton string wrapped element with a spring? First I've seen of this particular construction.
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-13.jpg)
Main pass transistor of the power supply:
![](http://s3-ap-southeast-2.amazonaws.com/stackfoundry-images/HP_5314A_teardown/5314a-sm-15.jpg)