Cleaning up and photographing a Hewlett Packard 5301A 10 MHz counter plug-on module for the 5300 series modular measuring system.

The HP 5301A counter module is compatible with both the 5300A and 5300B measurement systems. It can handle frequencies up to 10 Mhz and can display 6 digits on the 5300A display module and 7 digits on the 5300B display module.

It is a basic no frills counter with an external gate input, auto gate selection, three manual gate ranges, sensitivity adjustment, waveform selection, and check function.

Compared to the other 5300 measurement system plug-on modules, the circuit board is sparsely populated. There are 6 IC’s, and 9 transistors on the board, along with some other high quality passive components.

Most components on the board are dated from 1970, so that sets this module at just over 51 years old in early 2022. For it’s age the module works well, and just needed a general cleanup and some DeoxIT D5 on the front panel switch contacts to restore it to full functionality.

Unfortunately all of the front panel knobs are missing their center inserts and are cracked, but still function as needed.
I haven’t been able to source an online manual and schematic for this module yet, but will include it or a link if one becomes available.
Hi, I liked your site for the HP5301A. I recently found an old bench unit from my murky past, I am 82 and been retired a long time now. I noticed that you didnt have a Manual. I didnt either. A FREE abreviated ho-hum photo copy is available at (davmar.org) ‑https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.davmar.org/Spec/HP5301A.pdf&ved=2ahUKEwiCkcamz9SIAxVR7skDHblMHyw4FBAWegQIFxAB&usg=AOvVaw2pzVCcemIIACMmqEfkVtce . I am sure they will oblige you.
Have a great day Cliff Hall (Canada)