Nice! Lucky sod
. My guess would be mid eighty's judging by the case but I could be way off. Sometimes the serial number can give you a clue 089 week 0 1989? seems a little late for my gut feeling but maybe it was a legacy model still in production. Do you need a frequency counter or are you like me and can't resist sad puppy eyes and had to give it a home? ![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)
Thanks, yeah, that is pure luck and really exciting moment when I saw it and knew the price tag
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
My need for freq counter currently is covered and enough with my current agilent multimeter, so yes, its the impulse on giving this really bright shinning eyes (display) puppy a home, don't you ? Not sure these days, I guess youngster especially the 'just use microprocessor at everything' generation can not fully appreciate this kinda classic beauty.
I think it was from the late 70's, but if you open it up, you will see date stamps on the IC's.
The manual, including schematic is available, if you need it.
http://www.eserviceinfo.com/downloadsm/31091/Leader_LDC-823_823S.html
I am puzzled how you measured 49.999 Hz, as I thought the longest gate time was 10 secs which gives 0.1 Hz resolution. Did you measure period and invert? Or have Leader done something really clever to get the extra 2 digits of resolution in a 10 sec gate period?
My understanding is that this is before the era when counters got microprocessors allowing them to speed up measurements at full accuracy.
Richard.
You're right, thats a mistype, its the moment that I when powered up when I saw the 49.9, I knew this thing is still alive and still acurate considering it's age. It was a really exciting moment.
Anyway, thanks Richard for the heads up on that link, I was about to visit that site too for service manual, and just downloaded it, took a brief look at it and YES !!!!
![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)
its a pure discretes built counter, just check it out yourself at few last pages, it has the full schematic in there.
RE Discrete logic
TTL does NOT mean Trust To Luck.
A Flip Flop is not a form of footwear
Race Hazards are not a F1 pile up (and finally)
Slew Rate is not how fast you can get drunk.
Remember this kiddies and you will not go far wrong ![Cool 8)](https://www.eevblog.com/forum/Smileys/default/cool.gif)
Ha..ha.. I got one .... Psychiatrist is not needed even they're a confirmed bi-polar
![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)