Re: 7T11 horizontal memory


Albert Otten
 

Hi Chris,

One more suggestion. Set the 7T11 for MANUAL scan. Set the test scope at 5 or 10 us/div, trigger from the 7T11 pulse output. Then probe all TPs 512, 515, 525, 555 of the horizontal amplifier. In each period you will see one horizontal line at a level determined by the SCAN knob setting. The level increases from ground to some maximum when you rotate SCAN from left (ccw) to right (cw). The amounts and ratios depend on the setting of the 7T11 time/div within its range. At TP555 the maximum should always be 5 V.

Albert

On Mon, Dec 3, 2018 at 05:13 PM, Albert Otten wrote:


Hi Chris,

It's not so easy to interpret the graphs 26 and 27 the correct way. The shaded
area in 26 actually consists of horizontal lines, the value of which are
sampled when the memory gate conducts. In 27 something similar for the rest
period between end of hold-off and next trigger event.
When probe TP555 at a slow sweep speed, 5 ms/div, trigger from this signal and
play with the SCAN rate of the 7T11, you can get a more or less stable
display. You will recognize the 7T11 sweep as a rising envelope with an
amplitude of 5 V. The output at TP564 is a nice 2X inverted, down going sweep
signal with amplitude 10 V. TP556 shows about the same as TP564 but with small
amplitude.

Albert

On Mon, Dec 3, 2018 at 01:06 PM, cmjones01 wrote:


Now I have healthy gate pulses at the collector of Q546. However, I don't have
any sweep at TP555 in equivalent time mode. Need to look in to this next.

Chris

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