Mini Eliminator II modification

[Mike(Mont)]

I hope this uploads. Next time I'll try to figure out how to crop it.

I got this used Mini Eliminator II and it was pretty much worn out. I put a new IC8038 in it and it helped quite a bit, but I am spoiled with the ease and accuracy of the digital frequency generators so I couldn't help myself and made this hack. Just remove the IC8038 and hook up the generator wires + to pin 9 and - to pin 11. Pretty simple and it works great. I really do like this locator. I can feel the signal in my hands. Wished I'd got one of these a long time ago.

[Napsterce]

Nice job.

[Mike(Mont)]

:lol: Well, I just could be the world's worst photographer. I don't know how the photo got upside down. I consider it lucky just to get it posted. I'll see if I can do a better job next time.

[Mike(Mont)]

i spent about two hours trying to post another photo and gave up, P.O.'d. I don't care. But did want to say that Mini II has such a good signal I can feel it just walking through the line, even practicing inside the house. I'll go out on a limb and say I can feel it better than any other locator I have used. Darned near unmistakable. I had forgotten which room i tossed the target, and when I walked into the correct room it just like someone shocked me. And that's on the Medium target size setting which is half the power of the Small setting. Of course this is an above ground target and I did modify it with the DDS generator and probably running more power. Well, that's enough secrets to give out for now. :D

[Mike(Mont)]

Just a little free advice from someone who has been at this for over 35 years-- if you think you can do-it-yourself better and cheaper, and faster, well, you are living in self delusion. yeah, it's a hard-learned and costly lesson. Money, yes, but the real cost is time lost. I know most/all people on this forum hate the L-rods but like I said to someone, if you hate the L-rods you will REALLY hate the electronic locators. :lol: Price has no bearing. I know a guy said he tried one that cost several thousands. It did not work. One guy that spent eight years and tons of money on one said over 100 people had tried it and every one of them went back to their L-rods.

[Mike(Mont)]

And I said you probably won't listen. :lol: Speaking from first hand experience here, everybody thinks they are smarter than the next guy, smarter than all the electronic engineers, people with decades of experience in the LRL field, metal detector designers, yeah smarter!!! The old saying if you want to start a restaurant, get a job washing dishes first. Yeah, get-rich-quick fever is a serious illness.

[Mike(Mont)]

Got cold weather here so I have been practicing indoors with a twenty dollar bill and no L-rod. i just hold my arms out to each side and circle the Mini II until I feel the ion buzz in my hands. Just a little tingle right when my hand is over the line to the $20 bill. Not trying to brag, just that I can hit the line almost every time. No L-rod. :D Of course this is a very small search area. I like the paper money because when I toss it, nothing gets broken. And yes, the DDS generator has more power so I run it on the "Medium" target size. Otherwise it is not as easy to pinpoint on the "Small" setting. Just too sensitive.

[Mike(Mont)]

I guess I should say here if you don't know what you are doing, DO NOT ATTEMPT TO MODIFY. Have somebody who knows what they are doing do it for you. For starters, you need to ground yourself so no static electricity damages the circuits. Then you need the proper soldering iron--something with the proper temperature. And you need to be extremely careful not to damage the tracings. That means keep the soldering tip away from the board. And I do not recommend just sticking the wires into the chip socket. That will damage it for sure. I turned the board over and soldered to where the feet stick out the back. Tin your wires first and then just touch the solder tip to the wire. Don't even touch it to the feet. And you have to remove the IC BEFORE any soldering, and you leave it out--not needed. Pin 9 is "+" off the DDS output and Pin 11 is "-" off the DDS output. And then a good idea to turn the amplitude on the DDS down to less than 1 volt. And you still need the nine volt batteries in the device and turn on the power when using and also need battery for the DDS.

What you get is a device that has very accurate tuning with no drift, no warm-up time, easy to change frequency (no need to carry frequency counter), wider frequency range, I'm sure I'm missing something else but I think you get the picture. It's not that difficult to modify, just pull the IC and solder two wires. And I drilled a couple small holes to feed the wires through the side of the box near the nine volt batteries.

[ozanmelih]

Hello Mike. Do you still working on MFD locators? How is it going to?

[Mike(Mont)]

Hello Ozanmelih,

Yes, still "working" on the electronic receiver. Not much has changed since one year ago. :lol: I have never even taken it out into the field, so I don't really know how well it will work. And now i just ordered a copy of the "Inside The Metal Detector" book, so that will probably send me on ten different tangents. Sometimes I just can't help myself. :lol: But maybe I will learn something. I wanted to do some work on ground balancing GEB. Supposed to get here late this week. Still have a long ways to go on this project and I'm too slow.

[Mike(Mont)]

Just a quick update on the Mini Eliminator II. I for one never thought much of his equipment, mainly from what I was told by Dell Winders, not that he had ever used one. Bob told me a little of the development of the TRN. It evolved over several years. I don't know much about it, but the top antenna has a negative voltage and the ground probe positive. I did measure the resistance through the target size selector. Got 10 Mohms, 20, 30. These run through the top antenna. I held an transistor radio up to the unit and when I turned on the TRN I got a strong signal at the probe outlet. I checked it with a spectrum analyzer and there is some strange stuff happening with the harmonics. This thing is a lot more complicated than most people realize.

[Mike(Mont)]

Doing a little head scratching, not much hair left to pull out :lol:, I might have figured out how to incorporate the Mini Eliminator II into my contraption. I've been told sarcastically that I am no electronics genius. Tell me something I don't know. :D Yeah, I'm slow. This has taken me since November to get this idea. Haven't attempted it yet, so it might be a while before I know.

[Mike(Mont)]

Don't know if it was a swing and a miss or just a foul ball, but my great plans have folded like a house of cards. I still might be able to partially salvage the main TRN but at this point it will not be switchable--just TRN all the time. I don't know if that will work or not and i didn't try anything out yet. So tomorrow will see what happens. Right now, I'm real disappointed, but I guess I should save the crying until I know for sure. :barf:

[Mike(Mont)]

Obviously I don't know WTF I'm doing. That's the understatement for the week or year. I'm going by Carl's schematic, or at least what I think I understand about it. :lol: And Bob Fitz said it wasn't correct, so I'm beyond lost right now with a touch of delirium added in for spice. Well, I hope everyone gets a good laugh out of this. Laughing is good for you. Maybe I'm just over reacting and when I hook it up tomorrow it will work just fine. Okay, you can stop laughing now. :lol:

[Mike(Mont)]

Once again I am giving up on this quest. I got a signal but it was weak. Not knowing enough about the Mini Eliminator, I can only take a guess that somewhere the amperage is being reduced. I don't want to burn it up so this story is over.

[Mike(Mont)]

I don't know. It doesn't make sense to me. I thought for sure there would be plenty of power but maybe it needs impedance matching or something. Whatever the case it's getting too much for me. I don't blame the equipment, it's something I don't understand. Actually probably a combination of things--the two systems do not match.