I see the x-y inputs to the scope and you have a trace. To confirm the trace sweep is from the HP8601a: the scope is in x-y mode? If you remove the cable to the Ch1 input the trace descends to a dot?

If so, the display you show looks very much like it includes a marker. What have you selected on the 8600a? The control with the button depressed, if you rotate it does the dot move?

Please confirm this before we move on.

I don't see anything hooked to the "Channel 2 or Y" input. (?)

We haven't gotten to that stage yet. We are first trying to establish we can see the x trace with adjustable markers.

The HP8600a/8601a combo displays markers by briefly interrupting the sweep to produce a bright spot. Chris's scope is displaying that but he doubts it is the marker spot. I would like to prove that it is.

The marker frequency is read from the display of the HP8600a. The whole idea was to be better than beating the a separate RF spot frequency marker with the RF sweep to create a marker blip on the trace. It is supposed to minimize distortion to the swept signal.

correct, I have been playing with my monster analog scope a bit, and if you have it in the right mode, IF you unplug the line you have hooked to CH1, you should get a single non-moving dot on your scope, because ALL the sweep is from an external source, anything else, and it not in the right setting, and it wont work. but if it does show a dot, and then a line when hooked up, then... things a a bit more complicated. :tears:

I SEE IT!! I SEE IT!!

You have Trigger source set to line!
Try chan 1 int,
the way it is now nay be triggering from the line AC input and overriding the drive you are trying to give it.

Trigger is not used in XY mode.

You are prob right, but if so, then again, he should get no horizontal activity when the input to CH1 is disconnected.
No input = dot roughly in the center of the oscilloscope
CH1 connected = line sourced from alignment device

And changing the trig source switch (int/line/ext) should have no effect on the dot's movement at all, only input on CH1, if it's working the way it should.

info on scope here.
https://w140.com/tekwiki/images/1/1c/070-3827-00.pdf page 22

Scope is in X-Y mode. Marker dots do not move regardless of what I do to any of the buttons.

When I disconnect the X input, I just get a dot. There's sweep and I can vary it with the sweep width adjustment on the 8601. I just don't have any markers.

OK,, this just got really confusing then. :scratch2:
If it's all hooked as shown it should be working.
https://xdevs.com/doc/HP_Agilent_Key...0Operating.pdf
page 11

Given that all cables are OK.
Perhaps the marker is set up in an odd way, Pentode may be able to help there, it's clear that the oscilloscope and the 8601A Generator/Sweeper seem to be set correctly.

I really think there is an issue with the Counter/Marker 8600. Hey, imagine that...I bought a piece of equipment that doesn't work right. How unusual for me.

Too soon to say that for sure, debug it with Pentode and others who know the unit and try and work out what the problem is, it may just be set wrong.

All I can say is that it looks as if you are nearly there.

You have ensured the seep is coming from the generator? And the dot you cannot move pressing each and every button? Normally when the button is pressed to select a specific marker, the dot is brighter. I don't think it has been selected from the look of your display. It may be work playing with and cleaning the push button marker switches.

The thing that suggests to me something is wrong in marker selection is...

When I have the sweeper producing a 3MHz sweep around 50MHz symmetrically, I have the straight line on my scope but...on the display for a marker frequency on the 8600 after say I push the center button, the marker frequency that appears on the frequency display (our favorite Nikki tubes) is not stable. It jumps around very rapidly...too rapid to see so there is no way to select a marker frequency accurately. This is what gives me suspicions it is a hardware issue.

I wanted to do some basic function tests on the 8600. I've disconnected everything between the 8601 and 8600. I set the 8601 to put out a CW of 20MHz and I connected a cable from the 8601 RF out to the 8600 input jack on the front...at the extreme right. I believe this should make the 8600 a basic frequency counter. I get a real-time reading on the 8600 display that changes as I change the frequency on the 8601. This occurs when I have the scope button pushed in on the 8600. When I press the "CW Counter" button on the front of the 8600, I get a frozen readout of the RF frequency that does not change in real-time when I vary the frequency output of the 8601. If I go back to pressing the scope button, I get the real-time frequency read again.