Hi Nenad, The trigger circuits inside the 7T11 and the S-53 are quite similar. One difference is that the 7T11 can also do "HF Sync", a kind of trigger count down. Another difference is the implementa

It seems however that the 7A26 change is from -05 to -07 at S/N B208880. Jim Ford mentions a 20 pF plugin B19xxxx and a 22 pF plugin B21xxxx. I have S/N B198122 and B171610, both 20 pF and board versi

Hi Colin, Remarks only concerning the schematics: As far as I can see you can use there the proper values shown for CH2. The "Voltages and waveforms" page states that "if the 7A16A amplifier plugin is

I can confirm this, Håkan. For some reason I experimented with a 7704A, one plate disconnected, no signal on the other plate. After a sudden change in Position the dot follows but it takes some time b

Hi Daniel, Please note that not all types of ignition wires are suitable for this. With a piece of new copper wire cable the wave forms were rather useless. It was as if there were dielectric losses i

Hi John, If there is effect of the beam current on the bouncing back electrons then the effect would increase when intensity (so beam current and the B field) is cranked up. I didn't notice this. I al

In the Concept Series CRT book the 422 and 453 are listed as having a a mesh-grid construction but not so the 454. But the 453 and 454 schematics both show a grounded grid where the mesh-grid should b

Hi Chuck, I understand that there will be some random scatter around the theoretical "landing" point. But why does this lead to a fuzzy ring (at higher brightness the arc is a closed ring, with really

Chuck, How to explain that the ghost image of a stationary spot is not a spot but a (fuzzy) full ring of almost 1 div diameter? That's the situation in my 7704A and also more or less visible in the vi

Jeet, It might help if you can tell approximately where those dents are located. When I look at pictures I took from my 492P I can more or less judge the left and right hand sides of the frame. The on

Hi Max, I don't think so, but I got even more confused after other measurements in my 7704A. I measured the cathode current by means of the voltage drop across the 100 ohm resistor between supply and

Hi Max, So in summary you found in the bad scope that when you increase intensity from CCW to CW: - Logic board "FX" voltage first increases then drops again. In my opinion "FX" reflects CRT PA anode

Hi Max, But is that 1 V drop going monotonically, or is there a peak similar to what you saw in the multiplier current? Albert

Hi Max, I'm afraid the conclusion is now inevitable... In view of the somewhat open-ended topic "Mechanism of CRT Double Peaking" I wonder if all of the cathode current flows via the HV multiplier. If

Hi Max, Perhaps it makes sense to compare the beam currents of your 7854s . I suppose the voltage at pin FX of the logic board <4> reflects the multiplier current, and perhaps even more or less linear

Dave, Please forget my "calculated" value for the current in R112. I have no 7603, but my 7633 has the same schematic for this purpose. Also some voltages are shown in my 7633 manual. I did DMM measur

(continued) Sorry, mistake, current via R112 is about 10 mA, not 20 mA . Still with disclaimer... Albert

Dave, The RO signal that you see at U99C collector originates from R1101, so that tells nothing about the Z-axis logic at the lower half of diagram <2>. Did you test for continuity between Intensity w

Clever solution Max. BTW a 7B80 is somewhat more convenient for "B starts after delay" since then the B time base triggers automatically, regardless the Level etc. setting. I have sometimes used a +GA

Hi Max, "Minimum blur" but still blurr as optimum in stead of a sharp trace is a bad sign. You won't get it better with changes in the focus chain. Also even with some blurr present you would expect a