If anyone's looking for one, there's a new listing for a 1S1 sampling plug-in. https://www.ebay.com/itm/Tektronix-Type-1S1-SAMPLING-UNIT/284211115843

I tried a 10 MHz oscillator, actually three different ones by two manufacturers, and all gave the expected 10 MHz output - but with a rise and fall time over 5 ns. The waveform did rise considerably m

Thank you for the detailed explanation, Albert. I think I understand it now. So I'd need a much longer delay. 500 ns is about 350 feet of coax! Maybe I can use this sampling setup to help design a fas

Upon more thought... I tried turning the variable time/div knob away from CAL, which speeds it up by over 2:1. I can see the pulse at 10 ns/div (and center it with the Time Position knob) when using t

A careful reading of the 3S2 manual suggests that a pretrigger about 73 ns early is needed to see the triggering event. That may be why even 20 feet of coax was not enough of a delay line - would need

OK... I set the switch while in real-time to Smooth and the display looked just like the very slow rise/fall. I suspect the Normal/Smooth switch contacts were dirty. I have exercised them a few times.

Yes, it has the Pull for Sync switch (this is a 3T77A with the improved trigger circuit). The original 3T77 is only spec'ed to trigger up to 300 MHz, vs. 1 GHz for the -A). The back diode did fire mul

I'm sure I could make one of some sort (Googling "homemade tunnel diode" comes up with a LOT of results) but one that will have an Ip near 20 ma, trigger up to 1 GHz per the manual, and fit in the cli

Yes, both those controls work. The real-time mode still looks weird although now there is only one dot showing during the fall... still should not be any. I'm not going to go chasing that any further

How about a 1N4735A?

One of my 561's has a severely double-peaking CRT and it's not that bright. Voltages are in spec. It's probably not worth locating and buying a new CRT (especially if the USPS is going to handle the p

This afternoon I was busy tweaking the trigger circuit, especially the 10 ma leaded tunnel diode I'd tacked in place of the defective D42 trigger regenerator. Part of the problem was excessive lead le

And mine is definitely one of them! Chuck, I can send you a picture if that would help.

Does that include the 561B? I need one, once you start winding again :)

Turns out my request was #3 in line... but the #2 person thoughtfully yielded his place to me, so I could buy one. Thank you, anonymous Tekkie :) Despite the post office's best efforts to flatten it i

Me either. I finally ended up drilling a small hole in the PC board and mounting a sturdy solder lug, to which I fastened the coax connector and then soldered.. It took quite a bit of fiddling to get

I'm aware... the signal at the Vert Out jack looks identical :)

Sorry, I skipped a step (reinstalled the 3T77A). Actually I was referring to the time switch on the 3T77A. there are strange and inconsistent changes to the display when I turn it back and forth to th

Got them today (also run-over by a hand truck as I posted)... no damage though. The end that mates with the sampling head was easy - it snaps into the hole. Since the coax was a little short where som

Interesting you should mention that. Moving the Dot Response knob makes the trace move up and down the screen, but does little if anything to the overall displayed height (or the dots on the rise/fall