E-Trac project mod - shooting for a 3lb beast!

[earthmansurfer]

I have another E-Trac on the way after having sold my old one back in June (due to the weight/balance). I am shooting for a 3lbs or so mod and know it is doable. Here is a 3lb XS mod from Keith Southern that came out nice and it is similar to what I want. Explorer XS Mod

Basically I am leaning towards mounting an E-Trac onto an X-Terra 705 upper and lower shaft with a straight White's shaft in between. I will also use the shorter lower shaft (18") to save weight and since it's long enough for me. I want the front to be as light as I can since the the coil is on the heavy side. I would consider a fiber lower shaft if anyone knows of one that will the coil AND plug into the Whites shaft. I have to have the X-Terra handle part as it is as close to ideal as possible due to the screw wholes it has. I will keep the batteries as far back as possible (like in the above mod from Keith) and I will get that to weigh the proper amount to balance the unit. I think light weight Li-ion batteries will only hurt as I need the weight in the back. I need the shafts to be in 3 pieces, not 2, so that might rule out a carbon fiber system.
Any suggestions regarding to the above would be appreciated. Also, where can I purchase the straight White's shaft?

Does anyone know if the Whites Mono (3 prong) or Stereo (4 prong) headphone jacks are of the mechanical variety as far as shutting off the speakers?

I heard the Fisher 1266 battery box is ideal to use, but I can't find one of those. Any other ideas? I imagine I will just use a small kit box or the like that has room for the headphone jack. I think I will use a "4 on 4" one piece battery holder for the batteries and not a long one like the E-Trac has. This will allow me to get the weight farther back.

As I progress with the mod - starting with trying to take the E-Trac apart, I'll post pics here as to help any other guys who might want to do the mod also. (Any suggestions if the head/face is glued in place ?)

Thanks,
Albert

 

[stasys]

If you want I can sale you my Tejon shaft with battery box, but in your place I would use just extention cable, I use it all the time.

 

[stumppass]

An Excalibur battery pod will work perfectly as well.

 

[earthmansurfer]

I was able to take apart the E-Trac. All the wires and such are completely intact - NO CUTTING (yet). All said and done it took less than 30 minutes. I'll walk anyone wishing to take their E-Trac apart for a mod now:

Note - You can click on below pics and the pics will pop up big with good resolution.

1. Remove the battery.

2. Remove lower and middle stems, elbow cup and cut off foam grip on handle (unless you want to use soapy water and try to slide it off the back, I decided not to.)

3. Remove Pin from under Pod. You can do so by pushing it out, with great force, using a narrow screwdriver and then using a pliers at the end. (You need to remove the pin to slide the pod off rod later.) Here is the pin, partly pushed through.

4. Remove red "stabilizer/lock" or whatever it is called from the middle rod locking area, where the pin is basically located that you just removed. It practically falls out with a screwdriver. This also stops the pod from sliding off and must be removed.

5. Remove 4 screws from back of pod/faceplate. Here is pic of screws.

6. Then pull the face slowly off towards you. (Note - the faceplate pulls off, not the back) The wires can reach 3" or 4" no problem, but don't pull on them. (the foam grip is in the way if you haven't already cut it off). Big white wires are the coil wires. Other wires mentioned in step 7. Pic:

7. Now, pull off the two plugs on the right side shown above. They are for the speaker and the (power & headphone jack). The pull off very easy, but are on to fit tight, to make good contact. Pic of the plugs removed:

8. Start slowly wiggling and moving the pod off the rod. I just worked and wiggled it really slowly. It was off in just a couple of minutes. Good advice kieth gave me here. If yours is glued on, I think some CA debonder would help get it off.

9. Remove the 4 larger screws from the side of the E-Trac upper rod / arm. Remove the 2 small screws holding the stand on as well. You can safely take off the rest of the side plate now. Remove the stand and small metal square used to hold the arm cup on.
Here is how things should look now.

10. Now pull out the coil plug - it slides right out, easy. SLOWLY start to remove the wiring from the plastic crevice it is laying in. It is glued in places as you can see in the pic. That glue can and should be scraped off. It is soft glue and comes off easy. The wires pull out pretty easy. There was a lot of glue in the 6" or so area above the headphone jack. You want to separate the glue with a small screwdriver or the like here. Then the wire will come right out. The headphone jack and power spring thing slides right out, just like the coil plug. Here is the opened E-Trac pod with the one piece wire there.

11. Reassemble the Pod (plug in the two plugs you earlier removed). The cable plug sits safely in the area where the E-Trac's middle rod was. I imagine we can hot glue it there for the mod (that way you can easily take it off and for an E-Trac stock reassembly should you need to). This is as far as I got so I will stop with the mod here. (You should also reassemble the upper rod, keeps everything together nicely) Set the thing I called a "stabilizer or lock" and pin in a safe place.

It looks like we can re-use the headphone jack, depending on how and where we want to put it. The coil connecter looks like it is fine where it is and can be re-used as well.

Here are the weights of everything. I will use this to later compare against the new parts.

Pod - 14 ounces
Upper plastic Rod/arm - 14.3 ounces
middle rod - 4.44 ounces
lower rod - 4.16 ounces
battery - 8.82 ounces (yes, half a pound)
stock coil with cable - 1lb 2.6 ounces (This to me is a big part of the balance problem. I wish Detech would make a light replacement.)
Total - Almost exactly 4 pounds. Unfortunately, as stated above, the coil is heavy. But, the rear plastic arm is also a bit up there and the weight is spread evenly along it, as is the battery weight. Saving weight here and putting the replacement batteries at the way back end, like in Kieths mod linked on the first page, should really help with balance and weight. We will find out. Waiting on a few more parts.

Albert

 

[earthmansurfer]

A note in step 10 above - the headphone jack is in two pieces. You should put a piece of tape around it as it can easily come undone and you will lose a half.

 

[khouse]

Thanks for sharing. I've got some stuff ordered to lighten it up too. I don't have an exact plan right now.

 

[Rob (IL)]

I got my pod off today also. Albert is doing an E-Trac and I'm doing an SE. I finished my rods and cuff today. Mine is a 2 piece with just an upper S handle from a BHID and a lower Whites fiber rod. Looks like around
3 IL with a Li Po battery. The battery saves right at 8oz. We will see after I pick up the battery box tomorrow.

 

[khouse]

8 ounces just about covers the Sunray probe's 11 oz tax. I will get my parts all here and start on it when the snow flies.

 

[Rob (IL)]

I liked the Sun Rays but have sold them all. I couldn't see making a light weight detector and then add weight back on.

 

[khouse]

I understand. But the Sunray works so good on an etrac. You can carry the probe in your pocket to relieve some weight.

 

[ralphiejc]

Albert,I modified an explorer xs +explorer II about 10 years ago or so due to its weight and I wanted to use it in the water with waders..I separated the control head from the arm rest/battery holder and rewired for power(cant use the long minelab battery) and headphones.I ordered an S shaft from whites and called sunray to order an 8"coil with a 7 foot straight wire + plug.I `belly bagged` the control so all I swing is an aluminum shaft + coil.When I wade with it I strap it around my neck which keeps it higher than my waders.Looks a little awkward but the Explorer is `deadly` in the water where there is less trash.Ralph

 

[Critterhunter]

Earthmansurfer, looking good. So long as you are on a weight reduction kick, I'd ditch the internal speaker since I'm sure you use headphones like any other serious hunter. That speaker just unplugs by the looks of it, and it shouldn't be an issue should you forget to plug headphones in as there is no load otherwise to somehow mess the machine up. If you are still using the stock control pod then I'd cover the speaker hole vent with some plastic to keep out water or dirt.

Also, if you are trying to max out the weight savings, don't know what headphones you are using but I'd shoot for some studio style light/smaller headphones such as Sony Studio Phones. About 1/3rd the size/weight of regular headphones. So much more lighter and comfortable, and with great audio. I'm using a pair on my GT and they have the best audio of any headphones I've used on a detector over the years. Want to get a pair of Sun Ray Pro golds too though, as I hear the audio is very good on them and I also want the limiter and on-headphone volume control they have. I'll wear them in the winter months and stick with my Sonys for the summer. I hear the Sun Rays are pretty light too...

PS- If you go with headphones like the Sonys with a smaller headphone jack, replace the stock headphone plug with the matching smaller one. Pennies and dimes all at up to dollars, so every little bit adds up in total weight lost. That's how I dropped about a pound and a half off my GT, and without even touching the control box. Every gram or ounce saved will shock you in the end as to what it all adds up to.

 

[Rob (IL)]

Hey Critter, so far my rod setup, cuff, handle, grip, everything but the battery box and I'm 11oz lighter. I'm not giving weights because scales vary. I weighed all the Minelab stuff and then mine. I'm hoping the new battery can save me enough weight to get to 3 pounds.

Right now this is the box I want to get and mount like Keith.
[attachment 247127 2012-10-22_122644.jpg]
It's plastic with an aluminum cover. The weight is not listed.

[size=large]Did you ever figure my connector needed?[/size]

[size=large]I know I can weight the Minelab battery, but who's scale is correct. Does Minelab list their battery weight anywhere?[/size]

 

[Critterhunter]

Ain't been on there yet to check for any new emails from you, but I'll get to it or shoot me a PM here as I'm more prone to roam here more often.

Good job on the weight lost thus far.

Far as scales go, let me tell ya...if you pick up a good digital scale you'll find more uses for it then you ever imagined. I use mine to weigh my rc plane builds, silver, gold, stuff I ship, and of course my GT parts when I was building my light weight land rig. Found a good one at an office supply store for cheaper (I think about $22) than Walmart and such.

Make sure it's got at least a grams and ounces function, can weigh up to at least say 3 or 5 pounds, and you can zero out say a box you stick on it to throw stuff in as you weigh them (I think that's called a tare function or something). Comes in handy. If you get one that also does the other scale for gold/silver all the better. Mine doesn't but easy enough to convert grams to that, although grams are slightly higher in weight units I think so that has a bit less resolution when trying to figure out how much scrap gold or silver weight you've got for ARI or something.

PS- Lacking a digital scale, you can always head up to your local post office and use theirs, or use the local UPS store. Just tell them you are weighing it for planned shipping and were curious. Easier to pull that off than say using the scale at the supermarket.

 

[Rob (IL)]

I've got a good digital scale, I used it for charging AC units, grams, oz,.

 

[david.di]

The battery supply can be made up of 8 x AAA lithium batteries.

or a 12-14 volt lithium battery pack if there are any lighter than an 8 x AA.

You could also make light weight, slim line battery pod out of pvc tubing(make a timber model that is the same dimensions of the standard Etrac/Explorer battery pack) heat it up and use it.

The battery tends to act as a counter weight to balance your coil, so you may want consider that as well.

David Di

 

[earthmansurfer]

Hi Dave,

Thanks for the assistance. I thought Lithium rechargeables had too high a voltage to use 8 of them? Unless you were talking just straight lithium energizers or the like. But, it is good that you mentioned 12-14 volts as being possible. I wondered where Minelab placed the top of the voltage regulator at. I heard around 14-15 volts. The Li-ion pack I ordered is 2800mAh and 12-12.6 volts output (which I have yet to test).

The other thing, the battery acting as a counter weight - I agree whole heartedly with. That is why I am going to compare the (I think) lighter Li-ion pack mentioned above with 8X AA rechargeable batteries and see which one balances the detector better. But, you mentioned using the stock Explorer/E-Trac battery pack and I disagree with that for the simple reason you mentioned here - counterweight. If you have a long weight along the upper shaft, that will not be as good of a counterweight (considering the heavier pro coil) than a shorter but equally heavy battery pack at the way back of the upper arm. Do you follow me? I have not tested this, but I can't see how the stock pack, which is long, would balance as well as a shorter pack under your elbow. I am actually placing the balance above the weight, at least within reason.

You know, when I took the E-Trac apart, the pieces are really quite lite. The replacement rods are only slightly lighter, but as others have said, it does add up. In particular the upper rod. The E-Trac's upper rod is a bit heavier than a regular aluminum rod and the battery weight, as mentioned above, is spread along it. I think this area is where the magic really happens (though it of course is a collective).

If Detech could come out with a light Pro-Coil replacement (think of how light the 13" Detech is), that might "fix" the E-Trac's balance woes considerably.

Thanks for all the help guys,
Albert

 

[Critterhunter]

If balance is what you are shooting for, I wouldn't correct that with a heavier battery. Balance is over rated IMO if you get the weight down far enough. Think of it like holding the end of a yard stick. Who cares about balance it's so light? Now, if it was a steel pipe, then yea...not the weight makes balance an issue holding it all the way at the end.

But, either way, I say you can still have your cake and eat it too. Use the lightest battery possible, but then stick it on a back shaft extension far enough back to balance the detector where you want it. Hold the detector at the grip only. If it's balanced right the coil end should dip down to just above the ground. That puts it in a natural hunting position by way of a perfect center of gravity point at the grip. I got lucky. With my light weight GT shaft build I didn't care about balance, yet it all panned out that it balances right about at the grip. Best of both worlds.

Are you going to remove that internal speaker? Since it just plugs in I'd ditch it and just the inside of the speaker hole with plastic to keep rain/dirt out. You can always throw the internal speaker back in when you convert back to stock for re-sale if you ever do. I'm going to remove my internal speaker on my GT next time I have it apart. Those speakers are not light, and they give lousy audio anyway. I only use it for filming Youtube videos, but I'm going to tape a headphone ear bud over my camcorder mic for future filiming. Want to give it better audio that way anyway as as it stands all the videos everybody does use the built in speaker for filming and it makes people think it's got the worst audio in the world when in fact it's awesome. Just that the built in speaker makes it sound like a train wreck.

Sidenote on that: In the other thread going on right now here in the mods forum, somebody mentioned he stuck the wireless transmitter for his headphones inside his machine and directly to the stereo jack, and used a regulator to power the TX off the detector's battery. Perfect idea. Never thought of it. I'm going to get those $45 wireless headphones that Kbron2000 says work fantastic on his GT (some don't work well with certain detectors) and I'm going to do the same thing the other guy did on his detector- linear regulator to run the TX, with it turning on/off with the detector, and being able to plug in regular headphones and bypass the TX for normal headphone use should I ever want to. When I'm in there I'm yoking out the internal speaker to save a bit more weight. Can always throw it back in for re-sale, as I can also return the rest of my mods to stock easily too if I ever did re-sale, though I don't suspect I'll ever get rid of this machine no matter what I own in the future. Just too unique for certain styles/days of hunting.

My idea is to RF shield the TX and regulator in a cup of RF foil that is grounded just like the existing RF shielding, so that the TX/regulator is being sheilded away from the internal detector electronics. That way no risk of EMI generation that could cause the detector to false at higher sensitivity levels for loss of performance. The exposed end of the "cup" will be outward out of the control box so it can still talk to the headphones. I might have to put a capacitor or a choke or two on the regulator to keep it from causing noise in the voltage feed that might feed back to the detector, but being that they are both feeding directly off the battery a battery in it's self acts as a damper on circuit noise, so I might not even have to do that.

Off topic but a helpful hint. If any of you guys ever are trying to power a DC circuit and need a source, battery chargers for cars often won't work due to the EMI noise they generate, but if you hook a 12V lead acid battery between them it'll dampen out the EMI and do the job. I've done that with small 12V emergency light batteries (two 6V in series). They were too small in capacity to run the DC device I wanted to power capacity wise, but with a car charger combo I had the capacity I needed (endless from the charger), yet with the quite power source I needed (the batteries buffering out the noise). Worked like a charm...

 

[david.di]

Albert,

Sorry, that was meant to read 12 volts only, NOT 12-14 volts.

There are single AA and AAA Lithium Batteries 1.5V 2900mAh, 1200mAh nipple rechargeable's available. That is 8 x 1.5v = 12 volts. Given that an alkaline battery is 1.5 volts, you can use li-ion rechargeable or primary batteries at 1.5v, as well. That Li-ion 2800mAh that has 12-12.6 volts output that you mentioned sounds perfect. If it's smaller as or smaller than a pack of 8 x AAA Lithium Batteries 1.5V 1200mAh, it's even better. I found that, the nipple, rather than the soldered versions of battery pack recharging has had issues of mis connections when being recharged in their clips and most of the time, recharging them meant taking them out and charging them individually, that is separate from each other, even though there are chargers that can charge banks of batteries, the nipple types are never as good as tab soldered ones when doing this when made into a pack and where there is a more guaranteed level of connection between the batteries by using the tab soldered versions.

Yes, balancing that involves counter weight is a also factor and doing away with the original battery pod and doing what I said with creating a new one to accommodate the stock configured long Ex or Etrac battery packs is simply just a re-shaping of the pod, with only a small weight reduction, if your are trying to make a detector that has it's power supply on board, so your are right in placing the battery pack, much like like say, that of the CTX3030, which works great with the weight that is supposed to counter from the coil at the other end. Where it then gets pivoted, by where we hold the search stem when we carry it is what will also help us determining how it suits us. So I do understand.

Just thought I would also mention to you that, if you remove the speaker and block the speaker vents with a black silicone or a urethane sealer and also block all other holes of the Etrac control box , it'll become a very water proof control box on it's own that can be submerged and it does not require an external shell or another custom made control box shell and if you trace back onto the ribbon wire of the front button panel , you should also be able to find the pin point connections of the Etrac control box and wire them out to an external pin point trigger/ switch mounted on the handle of your new search stem( control box panel one still works). It's rather handy and I have had it on my chest mounted Explorer search stem since the word go. It save me letting go of the scoop or using both hands to operate what I can do with one.

First thing I did when I got the Etrac was open control box up and look inside to see I could decided on converting it for a water based detector and chest mount it like I did with one of my Explorers. At the end of it all, I guess all I was interested in was simply using it for dry land hunting, which I did a lot of and forewent any modifications, which I nearly did.........just before I got the CTX 3030. I've kept the Etrac original , because if anything , I am now of the opinion that the Etrac is light enough and can be balanced in another way that basically sees a battery pack mod, making it similar to the CTX3030 battery pack( a small group of batteries with their weight placed the most extreme opposite end of the coil rather, than being distributed along the arm.

None the less, 'tis great to see all the ideas that might inspire conversions/mods.

Disregard the roughness of my mod, it works as a waterproofed unit. Probably unsaleable but who's ever going to sell it anyway. The metal base box is also water proof and caries a bank of 8 x tab AA Nimh that a are recharged from outside. Whenever I connect to the coil , power and pinpoint buttons it gets a squirt of Inox, silicone spray or a new product that crc have brought out which is a non permanent spray on wax membrane, that water proofs the connections from the outside.

Can go all day in the water and on land without problems. Yes , the display is actually in your face , but I like it.

 

[Critterhunter]

If you are charging the batteries via an external plug so you don't have to go through the hassle of removing them to charge then coat the ends of the batteries with a very slight coat of dialectric grease (auto parts stores). It will prevent oxide build up that can happen with very low amp draws on devices like detectors. Just don't cake it on. Put it on and them wipe off with your finger so only a thin film remains. Too much will stop current flow on a low amp draw device.

I use the stuff whenever I unplug/plug in any electrical connections while doing work on my vehicles. It's great at preventing oxide build up and shorts on DC devices. If you are removing the batteries to re-charge then no need for it, as the act of removable/installation will clean the battery terminals.