Barracuda Legend Kit Problems

[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.

[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]

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?

[Michaelo]

Is there a need for the heatsink?

[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.

[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.

[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]

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 [ATTACH]35333[/ATTACH]

here [ATTACH]35334[/ATTACH]

Can you repeat at 200uS/ div? These still look wrong to me, I do not understand the first wider pulse or the pulse not being rectangular. Perhaps Kt315 or others can comment whether this is normal for a gate pulse.

If it is easy you might also be wise to try switching out the 40106. Those two gate pulse should not look the same. The second one should occur maybe 100 uS later than the first repeated at 600 Hz. Also check the power leads where they solder to the board, the joints look like crystals in the photos. Just reheat them and add a little solder. Check the whole board for cold solder joints. Check for any solder bridges and components that may have leads touching (r17 and 19 look close) on the component side of the board, focus on the area around the 40106. Something seems funny.

[6666]

try switching out the 40106

I've found a few faulty ones over the years, they seem to get damaged easily and are sold faulty, maybe bad anti static handling.

[Impulse]

ok i will try this later i have 2 i can try

[Impulse]

Hey guys i have changed the 40106 to a differnt one and this is the resault at pin2

here

[Old cart]

OK better, follow the items in #133, then leave this probe as is and add a second probe on pin 6 to the 5534. we need to see the relative timing. As usual we will need to see that trace. Sorry this is such a pain but it is hard to troubleshoot without "seeing"!

[Impulse]

Heres the 40106 pin2 and 5534 pin6

[Old cart]

Heres the 40106 pin2 and 5534 pin6

[ATTACH]35343[/ATTACH]

now try adjust the delay pot to near both ends of it taking two pictures one near each end.mThis still does not look right. Is the detector working?

[Impulse]

yes detector is working not great but is working

1k -

Max -