Whites Classic, II, III, ID, and IDX Modifications

[Koala]

Where'd you get those cool dial decals?

you can print your own with special paper

[Koala]

I would VERY MUCH like to know more about these opamp and JFET mods! I have heard about U4 and U8 (maybe others) being switched out for better components. And that coil mod sounds insanely cool! And a pre-amp in the coil? How cool is that? I am a HAM tech and that sounds just like how we bring in radio signals from around the world. Pre-amp at the antenna, not the radio! Please point me in that direction!!

If you are using the 8" coil. The biggest bump in performance would be going to the bluemax 950


Now you have the threshold POT you can use your machine on some wet sand but not all. No good in gullies or round rock pools but if the sand is fairly even just turn the threshold down a bit. There will obviously a small loss of depth to.

[Blissterd1]

My question was about opamps, JFETs and coil pre-amps.

[TH'r]

Where'd you get those cool dial decals?

Those are Ohmite Rheostat dials. Mouser #588-5007E. Additional knobs are from White's, and writing is Dymo tape writer. As you can see, I took out the frequency control and used that space for GEB.

[Koala]

My question was about opamps, JFETs and coil pre-amps.

Not much to be gained from changing to better components. You would have to increase the gain also but that would make the detector unstable in the field.

Not tried putting the pre amp in the coil.

If you are using the 8" coil the biggest bang for buck would be to change to the 950.

[IDXKevin]

A quick question...would there be an issue using 1/8 TH watt resistors in this project? Is the wattage critical? Thanks!
IDXKevin

[Blissterd1]

A quick question...would there be an issue using 1/8 TH watt resistors in this project? Is the wattage critical? Thanks!
IDXKevin

I wouldn't do it. The worst that could happen is that you might burn them up, but the resistors used in the machines are 1/4 watt. They are 6.3mm long x 2.2 wide. 1/8 watt resisters are half the length (3.2mm) and 1.9mm wide. The electron flow through them causes friction and heat is dissipated away. The 1/8 watt'ers will only require half the current to heat up the same amount. At full power, they will create twice the heat of a 1/4 watt. High heat in a resistor causes the rating in ohms to change well before it is destroyed. I would not use them for that reason alone. For the low cost, It couldn't possibly cost more than $2 to $3 for all resistors that are replaced. And you will only have to do the job once! Bigger is OK, but never replace a component with a current rating that is less than the original. Especially less by 100%.

[Blissterd1]

you can print your own with special paper

Clear paper with white inkjet printing or white paper?

[greylourie]

Clear paper with white inkjet printing or white paper?

Its special transfer paper. If you click the red "paper", you will get an idea....
Looks like handy stuff. Although results probably more durable if your printer uses pigment based inks.

[Lucas26]

Ok Just an update on R7 I have filed a return request for my 51K resistors that are actually 5.1k resistors.

[IDXKevin]

Yeah,that wouldn't have worked so well. Good eye to catch it before they got used!

[nelson]

I got a used whites idx, then i did the mods and let me said that this machine works excellent, even better than digital detectors that i have like Gerret AT gold, Tecknetcs T2, and many others that i have.
The detector only needs to have a low battery indicater. I use AA bateries at 2500mH and the machine can work for more than 5 hours continusly
I also have silverdog kit, never assembled, i think i will let it on the box by now if i need it on the future.

[Blissterd1]

I also have silverdog kit, never assembled, i think i will let it on the box by now if i need it on the future.

What kit do you have? The Surf Pi kit or the IDX Pro board? That's the only stuff I see there.

[Koala]

I got a used whites idx, then i did the mods and let me said that this machine works excellent, even better than digital detectors that i have like Gerret AT gold, Tecknetcs T2, and many others that i have.
The detector only needs to have a low battery indicater. I use AA bateries at 2500mH and the machine can work for more than 5 hours continusly
I also have silverdog kit, never assembled, i think i will let it on the box by now if i need it on the future.

I don't use a screen and use headphones but out of normal alkalines I get over 40 hours. Maybe a bit less in winter. I normally change mine after 3 full days detecting.

You can tell when the bateries are low as you don't get a positive beep in disc mode but still works fine in all metal mode.

There is a low battery LED add on posted deep in the large IDX thread

[tifred]

Hello.
this is my classic 1 modified classic 3.
Thank you to members of geotech.
This is exellent wet sand.
My first out this morning

Regards
Fred to Calais ,France