Barracuda Legend Kit Problems

[Impulse]

ok here is what i see at c11 to R20

[Old cart]

ok i have circled pin2 of the 40106 or the test point i used and where i think Junction c11 and r20 is? by jumpy i mean the small pos blips are moving around the top of the pulse erratically and it is hard to see what any adjustment is doing.

here [ATTACH]35318[/ATTACH]

and here is the list i have [ATTACH]35319[/ATTACH] just so that you can see what i am referencing

Those pins look right. Try the r20 c11 junction instead. You should see more prominent spikes there. I would prefer to use the gate signal but for some reason it is distorted.
what is was looking for was a schematic, not a parts list. Let's just use KT315s schematic.

[Impulse]

ok i have circled pin2 of the 40106 or the test point i used and where i think Junction c11 and r20 is? by jumpy i mean the small pos blips are moving around the top of the pulse erratically and it is hard to see what any adjustment is doing.

here

and here is the list i have just so that you can see what i am referencing

[Old cart]

Impulse, what you are looking for is a rectangular pulse about 45uS wide. It should very close to the rising edge of the NEGATIVE going pulse on pin 6. On everything is warm this should be set so the pulse appears to start right when the pin 6 pulse is returning to 0 volts or just a little before that. The image I have attached is an inverted version of what I am talking about. Your 45uS pulse should start about at T5 but you will have to tweak +/- a few uS from there.

[Old cart]

Impulse in that last image ch 1 looks wrong. Is this pin 2 of the 40106? If it is try instead the junction of c11 and r20. Double the trac height and overlap the traces.
I am using Kt315s Schematic he posted ( post 30 ) on this thread. Regardless, it appears the sample is now too far forward. No adjustments should be attempted until the circuit warms up and stabilizes. A good general rule of thumb with electronics is as long as you can hold your fingr on a component it is not too hot. That having been said cool is better if the circuit design allows it. What do you mean when you say the signal is jumpy?

Look at the trigger level it is close to the noisy top of the waveform. Drag it down to where the signal is nearly vertical and non noisy. This will give better trigger stability.

[Impulse]

Hey oldcart i have adjusted the first of the pos blips to about 10us it is quite hard as the signal is kinda jumpy but now i cannot replicate this situation using the scope after a while the 'blips' end up 30-40us out as the 9640 warms up? (it gets warm not hot)

see here





also

[Old cart]

A couple of more hints. Generally it is good to put the trace marker (number on the left side) right on the nearest graticule line when communicating remotely. This just makes it easier to see. When you are in front of the scope there is no such need. Also you have cursors, those funny dashed and solid lines in the menu, available to help. You will find there are horizontal lines to measure vertical amplitude, vertical lines to measure time, and both horizontal and vertical lines combined to measure both amplitude and time simultaneously. I recommend you start placing them on the traces at important places like at peak values, at the edges of pulses, etc. This will help facilitate communication. However you must accurately manually place the cursors to get accurate measurements. Later you will want to learn to use the measurement system to produce more accurate measurements. However, I would continue to confirm all measurements with the cursors until you have it all sorted.

It is recommended to run signal path compensation before you do any critical measurements. To do so remove all probes from the scope then let it warm up at least 20 minutes. The proceed as directed in the manual.

[Old cart]

ok heres with trigger raised

[ATTACH]35286[/ATTACH]

[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.

[Impulse]

ok heres with trigger raised

[Impulse]

o and yellow pin 3 and green 6

[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

[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]

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]

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]

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' ???