MINELAB F1A4 ex military metal detectors - tips, settings, questions

[Goldtarget]

I'm no expert but as a painter just go really steady on the stripper, and use something easily neutralized. Cotton bud top might be your best bet for applicator. Acetone works wonders, but perhaps try a bit of softening up with some diluted turps on a nice warm day before bringing out the big guns. Electronics are not forgiving to anything with a bit of bite.

 

[AtomRat]

I use Ethanol to clean my electronics boards when they are grubby and acid like. Not the easiest thing to get your hands on, but the next closest thing when I run out is metho as I have found it evaporates before it can do damage like eating or peeling at the board.

 

[stalker]

Is It enamel or acrylic paint they used. ..not being a smart ass but ethanol is also called ethyl alcohol and or pure alcohol . It's also In e85 . Very easy to get. I run my old valiant on It.

 

[mozzie1957]

Thanks all. Got a replacement from Jaycar and back on the board. Now just to sneak everything back into the box. Need the arms of an octopus.

 

[mozzie1957]

Woo Hoo, it WORKS!!!!!!!!!
What a bloody heart starter

 

[Guest]

Awesome..

If you can get the parts, you can fix almost anything on these old machines..

 

[mozzie1957]

Hi Mozzie,

That cap you broke is a 47uf 16v. Try and get a short one at they foul with the ferrite on the coil plug. The + side is closest to the edge of the board.
Don't use paint stripper, it is bad stuff and goes under the components and can cause headaches later on down the track.

Lt, please explain how you snap off a 10 turn trim pot?!

AuMan

You know how sometimes when you're de soldering something, and the bugger just wont let go?? well i figured I'd wiggle it a bit... gave it a little too much force and ripped the legs right off.. I've since purchased a far better soldering station, Hakko FX-951 Rhino tools one was a POS..

Reason i was replacing that pot, was because it controls tone.. Now my F1 sounds like a 2200.. happy days..

One of these days, which I'm rich and more infamous, I'll pay some bugger to level 2 me machine. In the meantime I'm adding a separate adjustable tone control.
Mounting it in a box with the amp. All trial and error, and swearing, but still a bit o' fun.

 

[Guest]

Mozzie, to save you the time and swearing, you can't adjust the tone from the output, it only acts as a volume control.

that little pot i spoke of above, that suffered an unintended decisive removal, that's where you want to adjust the tone... its 10 turn so you can get an alright tone out of it..

BUT! if you want a better range, get yourself a 20k or 50k liner pot... desolder (not using my method) the 3 legs, solder in some wires. connect to the pot.
Test it before you put things together, clockwise should be higher tone than counter clockwise..

Anyway.. yeah.. do that.. drill a hole in the front panel, and BAM.. tone action.

 

[mozzie1957]

How's one of these pots LT? 50k.

 

[heavymetal]

Desperately chasing 3 F1A4 detectors if anyone know where I can get them ! HELP !!! Thanks

 

[AuMan]

Mozzie, be careful drilling into the front panel if not done correctly you will rip it to bits. If you intend to get it modded at a later point in time, the holes need to go into specific positions. There's a bit more to it than just drilling a hole!
I would suggest just adjusting the on board trimmer to get a tone level that you are happy with, if it does not go low enough, replace it with a 50 or 100k 10 turn trimmer.

AuMan

 

[Guest]

How's one of these pots LT? 50k.
https://www.prospectingaustralia.com/forum/img/member-images/1655/1409227111_img_0744.jpg

Mozzie, AuMan is right on, I never explain things all that well..

You indeed need to be careful where you drill with these machines, small tracks run under the front panel.. take a look at where they put the toggle switches on the Level 2 modified machines.. those spots are 'safe' to drill..

Snagged the photo off google images since i'm lazy and didn't want to take one myself.

that pot you picked is perfect, it has what you would call a tiny arse! or footprint... So should fit in no problem. just make sure wherever it goes it isn't gonna poke something or short on the board (unlikely).. also make sure the case thickness isn't an issue, I removed my internal speaker (because they suck) so i had plenty of room for the Pot..

 

[Guest]

GL, they're getting kinda hard to get hold of.

 

[AuMan]

LT, the only place a pot will fit is in the centre area where the speaker lives.
As I said, there is a bit more to it than just drilling a hole, if you had drilled through these you should know this. Sorry, but I'm not inclined to give secrets away. If you figure out something for yourself, well good on you, but don't set about to just copy what someone else has come up with.
I hope you will give Mozzie a new end plate if he follows your advice and wrecks his, hopefully he does not wreck it.

AuMan

 

[Guest]

LT, the only place a pot will fit is in the centre area where the speaker lives.
As I said, there is a bit more to it than just drilling a hole, if you had drilled through these you should know this. Sorry, but I'm not inclined to give secrets away. If you figure out something for yourself, well good on you, but don't set about to just copy what someone else has come up with.
I hope you will give Mozzie a new end plate if he follows your advice and wrecks his, hopefully he does not wreck it.

AuMan

I'm not sharing yours or anyone else secrets, this is information available online...
I made mention of removing the speaker so as to fit the pot, apparently you didn't read that or don't care, too worried about all your secrets being shared..

I've not copied anyone, I post that picture 'which i will have Nugget remove' as representation of available space...

Mozzie and anyone else considering modding, I'm sure you all understand the dangers of modifying these machines.. If you aren't sure, ask or give it a miss..
I'm no expert, nor authority on these machines, I don't need to be, what i do with my detectors is my business.. If you decide to mod, do your research, the info i share has worked for me, might not for you.. Mod at your own risk, I've got a bunch of machines and enjoy tinkering, nothing more....

Again, Any info i get comes from forums like Geotech/detectormods/minelabmods/ etc etc... Its shared freely by others...

Disclaimer rant over..

 

[AuMan]

Ok LT, What I was referring to was your comments over on minelabmods. The tone mod is out there, that is fine.
I don't care about the picture, there is no reason to remove it. You did well identifying the safe drilling areas.

What I was referring to regarding drilling into the endplate, was not the speaker removal. This is quite obvious. Since the tone mod is out there, I will give you the bits of information that will enable people to drill their own endplate as safely as possible. What I was referring to is the slots in the speaker section. If you just drill through them as soon as the drill bit hits the slots, it will grab and tear the slots out as well as the decal.
So to prevent this, fill the slots with epoxy using a syringe applicator. Ensure to push from the decal side so the epoxy does not fill between the decal and speaker slots as this will make the area too thick and then you won't get the nut on the pot. Make sure you use the washer that comes with the pot too as this adds a bit of strength. Only fill the grooves, do not fill above the grooves as this will also become too thick. Allow at least 24hrs for the epoxy to set before drilling.

Then when it comes time to drill, use a 7mm drill bit. Carefully select your spot so your drill is centered between 2 slots and as far to the outside as possible leaving enough room for the pot to mount. The 4XXXX serial range has a bit more room, whereas the 5XXXX and above are a little bit tighter. You don't want the pot to ride up on the plastic ridge(5xxxx and above) as this will cause dramas. Use only light pressure on the drill, if you push too hard it will grab and then bye bye decal.

Once you have drilled the hole, then you need to either add foil tape on the back for grounding(this needs to be connected to the black wire), or you could also use some thin wire connected to the black grounding wire to ground the body of the pot. Cut the locating lug off the pot so the pot sits flat on the enplate once it is installed.

AuMan

 

[Guest]

Excellent information..

As to minelab mods, I've gone ahead and removed all those posts between myself a Barry.

Though I'm not sure what coil plug configurations, switch wiring, and a couple other minor bits of information was hurting, but hey.. better to be safe than kill someones detector with my miss information..

Anyway GL all.. Mod on! .. or pay someone who knows what they're doing... not me.. clearly

 

[AuMan]

Just an amendment to the above instructions where I said "Carefully select your spot so your drill is centered between 2 slots"
Should read "Carefully select your spot so your drill is centered in the slot between the ridges"

AuMan

 

[the duck]

Good information hopefully his detector should now work fine

 

[Guest]

It will, nothing he's doing (if done properly) should effect it in a negative way... Let us know how it works out Mozzie.