Troubleshooting the SurfPI longboard?

[gcause]

Hi All,

I had my SurfPI longboard working just fine and then I decided to put it into a proper case rather than the lunch box I had it in.

It stopped working, I must have shorted something when I moved it over to the new case.

Its getting power just fine and I have eliminated the power regulator I had added to it just in case that was the problem.

It wont make a noise when powered on. But it is getting power.

I did notice if I put my finger on the back of the board at the top right it will make a noise through the piezo but it has stopped detecting metal so I think I may have blown one of the chips.

I have a spare SurfPI kit so I could start swapping chips but is there a method for how you should go about troubleshooting a SurfPI longboard?

Regards,

Grant

[gcause]

Ok I fixed it, works just fine and is detecting metal again.

I decided to start swapping chips out and replacing them with the ones from my other kit. I started at the left and wouldnt you know it the blown chip was on the far right hand side.

The LM358 chip had blown. Swapped it out and away it went. Not sure how I managed to do that just shifting the board from one case (lunchbox) to another (jiffy box).

I would still like to know if there is a good method to diagnose problems with the board for future reference?

[Qiaozhi]

Ok I fixed it, works just fine and is detecting metal again.

I decided to start swapping chips out and replacing them with the ones from my other kit. I started at the left and wouldnt you know it the blown chip was on the far right hand side.

The LM358 chip had blown. Swapped it out and away it went. Not sure how I managed to do that just shifting the board from one case (lunchbox) to another (jiffy box).

I would still like to know if there is a good method to diagnose problems with the board for future reference?

The only proper diagnostic method is using an oscilloscope. Without one, it's like working in the dark.

[6666]

Its always the last chip

could have been caused by a few things
glad you got it going

[gcause]

The only proper diagnostic method is using an oscilloscope. Without one, it's like working in the dark.

Hi Qiaoshi,

I have one but it is only a single channel one and I have a multimeter.

What should I look for with the scope?

Regards,

Grant

[gcause]

Its always the last chip

could have been caused by a few things
glad you got it going

Thanks for that 6666 it is a great relief having spent so much time and effort on this project. Its raining ( flooding in some areas ) here so I cant get it out into the goldfields yet to test it out. Need to see how it handles highly mineralised ground as the SurfPI doesnt have ground balancing.

[6666]

Floods
Hey Grant the Surf PI is an underwater detector

A dual beam CRO is the way to go
however with a single channel cro
assuming that the TX part of the cct is working
you should be able to follow the pulse train from the output of the 5534
cheers

[Qiaozhi]

Hi Qiaoshi,

I have one but it is only a single channel one and I have a multimeter.

What should I look for with the scope?

Regards,

Grant

As 6666 said, a 2-channel scope is much better, as you can then measure the delays between different signals, such the time between switching off the mosfet and starting the main sample. However, a single-channel scope is still useful for checking each section individually. In order to understand what to look for, I suggest reading the Hammerhead article ->
http://www.geotech1.com/cgi-bin/page...head/index.dat
to get an understanding of how a PI functions.