the thing about old direct counters like the 524x series is that they take a direct count. gate opens, events are counted, gate closes. so there is no reciprocal math, no interpolation, no averaging, no nothin'. this means there is always a plus or minus one uncertainty in the least significant digit. but you can say your 5248 agrees with your ocxo standard to better than 1 part in 10^7. how much better? best not to ask or you will be down the rabbit hole of time nuttery.
have had lots of 524x counters pass thru my hands and have very rarely needed to replace a cap. maybe cub has advice on recapping? (if your obsessive compulsive tendency gets to you ok.....but probably not necessary).
never heard of a fan quieting fix for them either. only suggestion from me is to purchase a snubbie .357 mag and put a couple of ammo bricks downrange without ear protection. afterward the fan noise will be moot.
edit my recollection is .....that particular counter is ex air force. does that tmde tag on top say usaf? don't remember. you should be able to tell by the contract # on the tag stuck on the front. zoomies are all deaf from hanging around the flight line and can't hear fans either.
In my experience, the caps in those counters and similar gear of that time period are rather digital, in that they used very good ones and designed conservatively around them - they're either working or stone dead. Those that I've had to restuff were dead as doornails - either dried out or with one of the internal interconnects open. Those instances have been unusual; most are still chugging away.
Sahara Desert dry:
![](https://photos.smugmug.com/Electronics/Restuffing-can-electrolytics/i-K9VKcwV/0/51a3bc4e/M/IMG_8109-M.jpg)
Corroded connection - note the inboard end of the ribbon at 3:30 (manufacturing defect? contamination, perhaps?)
![](https://photos.smugmug.com/Electronics/Restuffing-can-electrolytics/i-jwjQnkd/0/16cd0c2c/M/IMG_8833-M.jpg)
And I know I've posted this before - my 5248M might need a fan...
As far as the can caps go, though, I'd leave them be unless they're bad - bear in mind that these are solid state, and thus run a bit cooler than your usual Tek room heaters that happen to have oscilloscope controls and a display, Mike. (Though if you decide to get OCD, you know what to do with the cans.
![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
) (And if they were truly OCD, shouldn't that be CDO? It's not alphabetically ordered!)
-Pat