Barracuda Legend Kit Problems

[Impulse]

yes i have tried the known signal first.

[Old cart]

yes i have tried the known signal first.

Ok ch 1 hot side to U1 pin 3, ch2 to U1 pin 6. Ground lead for both channels will almost always be on signal ground which should be coil shield or battery minus connection ( they should be the same). Adjust the controls so the smaller pulse is 2 div wide and fills the top half of the screen. Do the same with CH2. Set the trigger to channel one. You may have to adjust trigger slope for plus or minus slope so you can display the whole narrow pulse width. Tell us what you see or better yet attach images.

[Old cart]

Might I ask where you are located?

[Impulse]

also using the known signal i have set 1 and 2 probes up as per the setup so that the o-scope displays the correct value.

so can i ask that you point me in the right direction? eg point A to B for probe 1 AND Point C to D for probe 2, then what to look for and to do?

[Impulse]

Might I ask where you are located?

yes i am in kent near Canterbury

[Old cart]

Not far from Dover and where my KEF speakers were made in Maidenstone!

[Old cart]

Did you see my post 107?

[Impulse]

yes i have seen post 107 but i am struggling to get anything because i cannot connect the leads and leave them on there own as the 'grab' pins are to big to fit between the pins of U1 without causing a short so i have to hold the probes on pin 3 and 6 and try and set the screen, i have two solid lines no 'pulse' ???

[Old cart]

You can solder short test points to the board. A bent resistor lead formed into a circle at the top works well. Alternately you can connect the probe to a resistor or cap that is connected to the same pin. It is also possible to probe just one signal at a time. If the signal that you are triggering from is not present you will see nothing. Long term you may have to come up with finer probe tips.

[Impulse]

hey guys ok i have tried the scope on pins 3 and 6 i have taken a screen shot of what i get

here

so yellow is pin 3 and green is pin 6 on the 40106

does this look right to you?

[Old cart]

Impulse the setting are about but that is the wrong chip. It needs to be the 5534!, I think that is U1 on the KT 315 schematic. In addition raise the trigger level, the yellow T on the right side, until it is vertically further up on the waveform. Also, set the time base to 50uS per division and take a second shot at 20 uS per division. Lastly set the bandwidth limit to the lowest available 20 or even 5 MHz.
You might also select max min frequency and +pulse width from the measurements.
This ultimately will require a number of screenshots.

[Impulse]

Ok i have taken 2 screen shots one at 50us and one at 20us and i cannot adjust the bandwidth limit theres no option in the software





hope these are better

[Impulse]

o and yellow pin 3 and green 6

[Impulse]

ok heres with trigger raised

[Old cart]

ok heres with trigger raised

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[ATTACH]35287[/ATTACH]

Well Done, you are getting it! The second set are quite nice. This looks like everything is working well. It may be possible to slightly tweak the damping and get slightly better performance. But you are close. You will also find that slight changes in trigger level can make a big difference in how stable the signal is.
Do you see the tiny positive going blips on the yellow trace taken at 50uS with the trigg level raised? Those are likely where the main (1st) sample is being taken. The first blip should be moved to the left using the delay control up to about 10 uS. You want 1st of these two spikes to start right where the green trace finishes the linear part of its rise. You may have to tweak slightly +/- from there because this will have an large effect on the sensitivity to small gold.

However, before you do this remove the probe from pin 3 and move it to pin 2 of the 40106. This is the main sample pulse gate and shows exactly where this most important sample occurs. Change the trigger to ch2 and trigger on the negative edge of the green ch2 trace about the same relative level as you have been triggering on channel one. It is also desirable to make each trace fill the screen and superimpose them so that as little of the traces are obscured as possible. The whole objective here is to use the controls to get as much of the signal of interested on the screen as possible. The better you do this the more accurately you can measure the signal.

Send us that display.

While waiting for an answer You can search this forum and read about adjusting damping.

Later as you adjust the damping watching the green trace you may see significant change in the negative going pulse width and shape. Though you have the Dc level at pin 6 set about right you may find that this offset also changes the pulse shape and width. The green trace is after the preamp so shows what is getting to the sampler. You was to to adjust damping with only pin 6 connected as the probe loading on pin 3 can have a slight effect on pin 6.

After the damping is adjusted you may have to tweak the delay again. This is also true after you make any changes to the coil or coil wiring.

Damping, offset, sampling delay and threshold (for audio part only) all interact and must be adjusted in that order.