GPD-902 metal sensor mods

[americanflyer302]

Just recently purchased a Gardner Bender GPD-902 metal sensor to modifiy into a pinpointing probe using the instructions on tomstreasures.com . I just recently saw on another website with the same plans that some people are having problems with the unit failing after the modification possibly due to changes in the sensor itself by GB. Does anyone know anything about this and if this unit is still possible to modify I really dont see what changes GB could possibly have made to the 902 that would cause it to fail just by lengthening the leads to the ferrite rod. Has anyone made a probe out of this unit and how well does it work

 

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[Dragon]

I just finished making mine this morning, took about an hour, and it works absolutely fantastic. I did not have to make any changes or adjustments to the potentiometers on the PC Board. I used two pieces of twisted pair wire from an Ethernet connection cord and made sure to dress the wires from the ferrite rod antenna straight down the side of the rod, and was careful not to criss cross them. I also made the probe rod go the other way from the original design. Makes for easier handling. Total cost was less than 13 bux. Here are the links if you want to make one for yourself...

http://dlclark.tripod.com/902.html

http://www.thunting.com/cgi-bin/geo...l?page=metdet&file=/projects/probe1/index.dat

Here's mine...

 

[JAB]

I have just purchased a GPD-902, and plan to build a detector probe as outlined below for my daughter to use while we're out detecting. As someone who works in the electronics equipment industry, I know that the manufacturer would not waste their time changing the design of this unit just to foil detectorists. This item is made in china, but is probably designed here in the good ole' USA. There is no cheap design change once an item is being manufactured. The manufacturer probably has an inventory of boards, parts, etc., and some of it may have to be scrapped if the design is significantly changed (which costs them money). Typically, changes are made due to significant cost savings, design flaws, or safety concerns. The components appear to be very inexpensive, and it is likely that the failures are due to flaws in one or more of the GPD-902 components. Remember the old adage: "you get what you pay for." Fortunately, the parts to build the detector are cheap enough to take the risk.

Thanks for the modification plans, Dan!

 

[Dragon]

For 8 or 9 bux it's worth the fun! I don't see why a longer pipe can be used and hooked up to a larger coil. Should work just fine.

John

 

[quailbird]

I just finished making mine this morning, took about an hour, and it works absolutely fantastic. I did not have to make any changes or adjustments to the potentiometers on the PC Board. I used two pieces of twisted pair wire from an Ethernet connection cord and made sure to dress the wires from the ferrite rod antenna straight down the side of the rod, and was careful not to criss cross them. I also made the probe rod go the other way from the original design. Makes for easier handling. Total cost was less than 13 bux. Here are the links if you want to make one for yourself...

http://dlclark.tripod.com/902.html

http://www.thunting.com/cgi-bin/geo...l?page=metdet&file=/projects/probe1/index.dat

Here's mine...

Where can I get the plans for this GPD-902? I am new to this forum!

 

[Jason in Enid]

Where can I get the plans for this GPD-902? I am new to this forum!

Congratulations! You have revived the oldest, deadest, thread I have ever seen! You are asking questions of people who have been gone for probably close to a decade. Next time look at the thread date before you respond.