Tektronix 2200 Series Minimum "B Delay Time"

[Michael J. Linden, N9BDF]

I've got a Tektronix 2236 Oscilloscope that has a delayed-sweep feature
in which an intensified portion of the A sweep is magnified and displayed
on the B sweep after a specified delay. This feature is shared by other
Tek 2200 series scopes like the 2235. But in the case of the 2236, the
delay time is displayed on an integral nine-digit fluorescent
counter/timer instead of on a calibrated multi-turn knob.

I'm trying to find out if there is a problem with the delayed sweep
feature on this scope. I initially assumed that when I turned the "B
Delay Time Position" fully CCW, I should have a delay of zero seconds.
However, I can only get the delay down to about two minor divisions (this
is constant regardless of the horizontal time). The good news is that the
delay displayed on the integrated counter/timer always agrees with the
delay that I see on the CRT when I place the triggered edge of the
waveform on the leftmost vertical major division.

So, my question is, is it normal that the minimum obtainable delay time
is about two minor divisions on the Tek 2200 series scopes or do I have a
calibration issue?

Thanks, Michael N9BDF

 

[Jim Yanik]

"Michael J. Linden, N9BDF" <m.linden@computer.org> wrote in
news:V46dnVq10LoJqd_fRVn-tQ@rcn.net:

I've got a Tektronix 2236 Oscilloscope that has a delayed-sweep
feature
in which an intensified portion of the A sweep is magnified and
displayed on the B sweep after a specified delay. This feature is
shared by other Tek 2200 series scopes like the 2235. But in the case
of the 2236, the delay time is displayed on an integral nine-digit
fluorescent counter/timer instead of on a calibrated multi-turn knob.

I'm trying to find out if there is a problem with the delayed sweep
feature on this scope. I initially assumed that when I turned the "B
Delay Time Position" fully CCW, I should have a delay of zero seconds.
However, I can only get the delay down to about two minor divisions
(this is constant regardless of the horizontal time). The good news is
that the delay displayed on the integrated counter/timer always agrees
with the delay that I see on the CRT when I place the triggered edge
of the waveform on the leftmost vertical major division.

So, my question is, is it normal that the minimum obtainable delay
time
is about two minor divisions on the Tek 2200 series scopes or do I
have a calibration issue?

Thanks, Michael N9BDF

I believe that is normal;while at TEK,I used to have a chart of the
different minimum delay times for each model of TEK scope.
(for setting the 10-T precision delay pot)
The service manual should have the spec for your scope,in either the
performance check or cal procedure.

According to my 2215 manual;

Horizontal
Step 2a;set;Ch.1 gnd
Horizontal mode alt
A and B sec/div 0.2ms
b; align the start of the A sweep with the 1st vertical graticule
line.
c; Check-Intensified portion of the trace starts within 0.5 division
of the start of sweep.
d; rotate the B delay time position control fully CW
e; Check- Intensified zone is past the 11th vertical graticule line.

The 2236 may be slightly different due to the counter-timer readout.


I don't have a 2236 manual.

--
Jim Yanik
jyanik
at
kua.net