Whites IDX mod with analog meter?

[Leeinsc]

I've been a lurker on the forum for a while. Don't have the skills or knowledge to do any of the cool mods, but I did have a friend with the required skills mod my Classic IDX with the MR. BIll mod and love it. I saw the VID mod and was wondering if it is possible to mod the IDX with an old analog meter like those on the Whites XL Pro. I'm sure some of the gurus on the forum know the answer. Thanks for your time

Leeinsc

[scrungy_doolittle]

meter

I've been a lurker on the forum for a while. Don't have the skills or knowledge to do any of the cool mods, but I did have a friend with the required skills mod my Classic IDX with the MR. BIll mod and love it. I saw the VID mod and was wondering if it is possible to mod the IDX with an old analog meter like those on the Whites XL Pro. I'm sure some of the gurus on the forum know the answer. Thanks for your timeLeeinsc

I've been wanting to populate the meter portion of my 4900di pro, but the schematic does not show the meter. There are some schematics floating around of the 6000 and 5900 here on this forum, and they give the schematic for the meter circuit. It lists a dual transistor. the origin is not available any longer, but there is a replacement. Can't remember the number. There is a lot of circuitry associated with the meter, including some log amps. Basically a transistor in the feedback loop of an opamp, forms a logrithmic scaler, which is used to actually compute the phase angle.The phase angle of the metal (which gives your ID is basicall arctan(x/y). an approximation can be derived by simply doing x/y. to do that in analog, means converting X and Y to logrithms and then subtracting them. So if you use a log amp on the x channel and a log amp on the y channel, the voltages are now converted to a logrithmic representation. They can then be add for multiply and subtracted for division. An op amp adder effectively does this, with the result being a voltage that is at least proportional to the slope of the phase shift, which is then used to drive a meter.There are two VID's on the forum, one based on an arduino,. they work by using a ADC to measure the X and Y voltages, converting them to floating point and doing arctan(x/y), and a bit more tweaking, and that becomes the VDI.Unfotunatly, I hook power up backwards on my geotech VDI lst night, and think I fried it.... sigh

[Leeinsc]

Well, you lost me at duel transistor. I have seen a digital a VID mod on the forum out of Europe for the IDX machines, but I think it is no longer available. Thanks for the reply. Maybe someone with more skills than me will figure it out and post instructions. I have a friend who definitely has the skills to do it.

Lee

[sinclairuser]

whites uk sell a 3900 pro plus with an analogue meter, its a uk only model sold in the professional section, i have two an older one(black meter), and a brand new one(yellow meter).
they are fantastic machines mostly over looked, but for 230 pounds you get a robust real professional detector for budget hobby money, if you can find the connection points for a 4900, then this meter setup may work for you.
i tried the black meter on my idx and it worked ok, though it was not as sensitive as when fitted to the 3900 pp.
connection info for 3900 and idx are on these boards somewhere(thats where i found the info), and 4900 and 5000 may be too, you should be able to come up with what you need, the trick here is to bump your thread now and again untill the user who knows what you need is here, there are users here who know exactly what you need.

[Leeinsc]

Thanks for the info. I'll do another search and see what I can find.

thanks again,

Lee