It's not weird but perfectly normal. What you see is a Dot response about 75% (upper trace) and slightly less than one (lower trace). Soaome asymmetry in dot response between jumps up and jumps down i

These are nice results Charles! Although less important now I wonder about the previous strange result in real-time mode. Is that still the same? In equivalent-time ranges of the 3T77A, do the DOT res

I exchanged my waveform pictures in the 3S2 album by one more relevant picture. The important part of the S-2 output occurs within 0.5 us or so and was not well visible in the earlier pictures. Compar

In hindsight I realize that the waveform at TP121 will also depend on how fast the feedback will react on the new sample. That's probably why TP121 waveforms for the S-1 and S-2 are shown separately i

Hi Charles, It would be interesting to look at the S-1 (or S-2) output at pin 4. Accessible at TP121 <1> of your 3S2. This happens to be also TP121 in the 7S11. You don't need a time base in the 561A.

Channels A and B have one thing in common: the 100 kHz source (free running dual trace drive at diagram <5>). Slow state switching there might have effect in the otherwise separate gate driver circuit

The time/div setting (3B3?) is not involved. You might mean the "units/div" vertical sensitivity setting. The block diagram shows that channels A and B have their own circuits up to and including memo

Hi Charles, I saw now that the 3S2 also has a NORMAL-SMOOTH switch. (My 3S1 has those labels more prominently above the switch, that's why I missed them at first sight at the 3S2 picture in the manual

Hi Charles, I can easily imitate the "staircase" effect, see the picture Real-time.jpg which I added to your album https://groups.io/g/TekScopes/album?id=261250 . Very likely your loop gain is far bel

Hi Charles, This is probably because the purpose usually is to display/measure rise time. A real-time time base needs a pre-trigger for this. If you have a stable repetitive signal then a sampling tim

The PG506 and PG506A have the same spec 1 ns for rise time (to zero) of the fast pulse outputs. The TD pulser 067-0681-01 is mentioned under as Optional Accessories is faster caibration aid but is no

That's not correct. Is the time base really running in AUTO mode? You should get a horizontal trace near the center line. My first choice is a P6009. Albert

Be aware that the missing trigger connector affects the Transient response of the S-1. The transient response amplifier (Q13/Q17) will do almost nothing. The 7S12 cannot be triggered internally by the

Hi Peter, Your 7704A should work fine with those plugins. Because of the beamfinder result there likely is a balance fault (one signal path defective?) in the vertical amp. You might start with examin

Hi Charles, The diode is shown in the 564 schematic, being added at 564 S/N 2980. From the serial numbers of my 564s I conclude that this must have been somewhere in 1964. You undoubtedly were the fir

I meant ordinary wire except for the coax lines.

Hi Charles, You will have seen that the coax to pines 3 and 4 has a crossover between left and right connector. For fault finding in the 3T77A I would do as in the time base connector, that is with br

" it only brightens a portion of the trace corresponding to the time/division setting " Isn't that the LOCATE button? Albert

Hi n49ex, Are you using a sampling head with trigger signal output? If not (for instance S-6) then you have to supply external triggering to the 7T11A. Albert

No, in hindsight (after reading your messages once more) I see that your 'scope very likely has another problem. After some searching in the manual I found U1720 at diagram 25, board A29. It would hav