Barracuda Legend Kit Problems

[Impulse]

Ok so i have set the delay trim to 12k Ohms, i have also put the scope on the Gates of top and bottom FETs circled

here

[Old cart]

Is there a need for the heatsink?

they never hurt. Electronic components work best when they are at a stable and near room temperature.

[Old cart]

Impulse ultimately we have to sort out two things

1. Making sure those sample pulses are the right shape (rectangular). width (45 uS) and position relative to the transmit pulse. So far we are either probing wrong or the 40106 or FETS are broken.
2. That the coil is ultimately damped correctly. ( Have you read damping threads yet)

Of of course there could be other issues. For example some of the ic's look as though they may not be fully seated in their sockets. You can push those down firmly now.
While we do this do not become distracted with measuring depth of detection though you can certainly wave a coin near the coil to make sure it is still working.

The good news is it is close to working correctly!

BTW the pictures helped clear things up a lot.

[Michaelo]

Is there a need for the heatsink?

[Old cart]

Hey old cart i have a rev2 board there is a link between those two points? and no i havent got any 10k pot i thought the 25k delay trim was the only adjustment

heres the pics
front [ATTACH]35325[/ATTACH]
back [ATTACH]35326[/ATTACH]

It is fine if that is jumpered but you must then very careful that the trimmer is never set to 0 ohms. I would set the delay trimmer to the mid position by counting turns alternately you can measure resistance with the power off between the center pin and the pin not connected to the center on that trimmer and set it to 12K ohm. Then put a scope probe on the G pin of each Gate FETS. There are the 2 devices next to each other right below the 2 caps on the top of the board as viewed the from the component side. For all measurements put both of the scope grounds on the shield lead very close to the board and to each other. Adjust to 50 uS per div and send me the pics. In this case adjusting the delay will have no effect of the position of these gate pulses becuase you are trigging on them. This makes them the reference position horizontally. It does appear that your model does not have a position adjustable trigger. btw did you ever figure out how to move the trace horizontally? I think you can drag it with the mouse or maybe use the scroll wheel. What do those two arrows do above the screen?

[Impulse]

Hey old cart i have a rev2 board there is a link between those two points? and no i havent got any 10k pot i thought the 25k delay trim was the only adjustment

heres the pics
front
back

[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

referring to your baracomp.jpg file look at the two pads labeled delay. That is here you should have a 10 k pot (external with knob) attached. If the pot is missing the delay wil not work right. The trimmer is intended to adjust the minimum delay. This pot is to be case mounted to adjust the averall delay to adjust the detector to reject small items like foil. You must have both. Was it not included in the kit? See also here for more detail http://www.geotech1.com/forums/attac...4&d=1378894850

A good clear picture of both the front and back of your board would help us resolve this. I think this may be the problem.

[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

in the parts list you attached here they describe a 10 K pot that is presumably an external control with a knob on it. Do you not have this? The general difference between a trimmer and what is called a pot is that a trimmer is typically a screwdriver adjust, a pot is a hand adjust. They are both actually potentiometers.

[Old cart]

Well let me think-the last trace is unusable. There is no rising part of the waveform.

It appears I was looking at the 6952 manual where it does have trigger position. I guess the 6022 does not. I wonder if it just a matter of software? Unless you are very experienced with the PC it is probably best not to try the higher end models software.

[Old cart]

r10? is the 25K blue pot on the board that says 'delay' under it ?

so there is only 1 delay trimmer and no external off board delay pot?
as for the image this is not the right rising edge. I need the rising edge after the 45uS. Can you maybe grab the waveform and pull the whole waveform with the mouse to the left? Best to start with the setup before this one.

[Old cart]

Well let me think-the last trace is unusable. There is no rising part of the waveform.

[Impulse]

When you adjust delay are you changing r10 ( the 25k trimmer) or the delay pot?

r10? is the 25K blue pot on the board that says 'delay' under it ?

[Impulse]

no i cannot change the trigger position horizontally ok tigger is neg slope now tigger level 1V and time/div 5us.

here

[Old cart]

When you adjust delay are you changing r10 ( the 25k trimmer) or the delay pot?

[Old cart]

ok here is what i see at c11 to R20

[ATTACH]35320[/ATTACH]

Getting better with your settings! Change trigger to neg slope, drag trigger level so it triggers about half way down falling edge (1 volt) . Can you move trigger position horozontally? If so move trigger position about .5 div from left. Set time per div at 5uS. What we are trying to do is increase the resolution on the slow rising edge.