What I am looking for folks, is the small red knobs used on a variety of Tek plugins. In this case, they are needed for a 3A74 amplifier (in photo). These knobs are approximately 3/8" to 7/16" long, and 7/16" in diameter at the small end. The hole is 1/8". Additionally, I need the locking/clamping assembly found on the 2 and 3 series plugins. Need the entire assembly. In both cases, could use at least a couple of each, the knobs and locking assemblies.

Thank you guys and gals, much appreciated.

You’ll probably have a way better chance at just getting a scrap plug in. They show up at auctions, hamgests, shows, the occasional estate sale and of course the bay

Not that hard to come by. PM sent.

Looked at some of the junk on the 'bay, but I am reluctant to drop $50 or $75 for a scrap plugin. Call me cheap, but the likelihood of getting enough goody out of those units to make it worthwhile in my lifetime is about nil. There may still be the occasional decent deal, but I haven't ran across one for some time.

Last time I was at Fair Radio in Lima, Ohio he had dozens of plugins on a shelf, and more than likely has extra knobs in a separate bin which were saved from other scopes that were parted out over the years.

Forgot about Fair Radio. Bought some stuff from them years ago. Will give them a call. Didn't see anything on their website. Thanks Dennis.

Google "Qservice". They have a category just for Tektronix knobs.

I have following knobs.
Please let me know if interested:
This are from more "modern" Tek, but may work...


Thank you,
Aram.

Thank you Aram, but I'll pass. In the interim, I have swiped a knob from my 3T77 Sampling Sweep generator. Hate taking parts from instruments in the repair queue, but since I intend to use the 2A74 as my regular amplifier in the 561A (at least for awhile), the knob will at least make the plugin "whole" since it now joins the ranks of the living.

I have quite a few Tek knobs, don't know about that size, since I'm not at home right now - will be a week. There's a bag of 1/8" shaft knobs. The locking mechanism is threaded rod, aluminum knob, c-clip? May have that too.

Great Tom. Not in a big hurry. Would just like to put all the parts I pulled from my other plugins back, and have a few spares.

The locking mechanism contains the knob, threaded shaft, housing/bracket, locking finger, tension spring, and the keeper. The "keeper" is an "X" shaped affair. To remove the keeper from the threaded shaft, you have to squeeze two of the legs together to open up the legs that are on the end of the shaft. A bit of a bear.

I don't really need the housing/bracket, but could use the rest of the parts. Could also use a couple of the nylon/plastic guide feet that are on the bottom of the back plate of the 560-Series plugins. Had to swipe one of those too.

Found 3 so far.

I pulled these from the bag of Tek knobs - four (needing cleanup...) have a 3/16" shaft, 0.56" dia., 0.54" long. Rest are 1/8": - two 0.5" dia x 7/16", one 7/16" dia x 0.5" long., may have more of all of them. Don't have the locking parts except for the knob - 3/16"?