Vallon VMH3CS Mine Detector

[Mdtoday]

One problem that has been raised in this thread, is that the balance of the VMH3CS is a bit coil light due to the heavy D batteries which weigh about 140gm each. Today I received some AA to D battery converters in which you can put 1-3 AA cells. I have some rechargeable ones with a capacity of 2300mAh so 2 cells in each converter give 4600mAh. Each of these pseudo D cells weighs 75gm so there will be considerably less weight on the back end of the detector to bring the coil down. It should run the detector for about 15 hours so no problems there.

I have a scrap Vallon battery tube, so I loaded three pseudo D's into that and charged them all up together. Everthing worked fine and the detector felt much better balanced. As you have seen from my recent posts, I have a range of coil sizes, all of different weights, so now I have more options to get the best balance. Put another cell in each converter, or leave one out, plus adjusting the length of the telescopic shaft.

The converters I bought appear to be rugged and the AA batteries fitted snuggly. In fact they need not be removed from the 3 converters as the whole lot is charged together. In old money, the detector is about 0.5lbs lighter with the 2 cell arrangement.

Eric.

That's a good idea, more options, better balance, less weight, has to be a win!

Brian

[Ferric Toes]

AA batteries for Vallon power

One problem that has been raised in this thread, is that the balance of the VMH3CS is a bit coil light due to the heavy D batteries which weigh about 140gm each. Today I received some AA to D battery converters in which you can put 1-3 AA cells. I have some rechargeable ones with a capacity of 2300mAh so 2 cells in each converter give 4600mAh. Each of these pseudo D cells weighs 75gm so there will be considerably less weight on the back end of the detector to bring the coil down. It should run the detector for about 15 hours so no problems there.

I have a scrap Vallon battery tube, so I loaded three pseudo D's into that and charged them all up together. Everthing worked fine and the detector felt much better balanced. As you have seen from my recent posts, I have a range of coil sizes, all of different weights, so now I have more options to get the best balance. Put another cell in each converter, or leave one out, plus adjusting the length of the telescopic shaft.

The converters I bought appear to be rugged and the AA batteries fitted snuggly. In fact they need not be removed from the 3 converters as the whole lot is charged together. In old money, the detector is about 0.5lbs lighter with the 2 cell arrangement.

Eric.

[kingswood]

Well almost the full kit, as I have a few other ideas to investigate.
All I need now is an unthrashed area with lots of buried treasure. Nuggets, rings, coins or Spanish gold will do.

Eric.

[ATTACH]39793[/ATTACH]

Excellent work Eric!
Looking forward to seeing photos of all your good finds

[Mdtoday]

Hi Nelson,

Yes they are quite sensitive aren't they.
I'm so please that Eric started this post as I would not have been on the look out for a Vallon otherwise.
Hope you have fun with your detector.

Brian

[Mdtoday]

[QUOTE=Ferric Toes;231920]Well almost the full kit, as I have a few other ideas to investigate.
All I need now is an unthrashed area with lots of buried treasure. Nuggets, rings, coins or Spanish gold will do.

Eric.

/QUOTE]

Really nice job there Eric, great bit of kit!
Yeah, a bit of Spanish gold sound good

Brian

[Mdtoday]

Be careful, as the end cap of the main box is not symmetrical. The coil cable goes in via the hole on the left in the front view. You can see a fibre washer and under that is an O ring. The black aluminium tube screws down on this to make a watertight seal. You will see spanner flats at the other end of the tube. Notice that the bottom edge of the cap steps down a bit; so now look at the inside view. The molding is full thickness where the cable comes through, to accommodate the seal and the threaded section to screw in the tube.
You cannot have a similar tube screw into the other side (left) as there is not enough thickness and the hole cannot be on the same level which is right on the inner lip of the end cap.

Eric.

Ok, yes I see the problem, I thought there would be a bit more thickness but had not taken the end off to investigate, thanks for pointing it out Eric.
I will think about it and come up with a solution.

Does the battery tube assembly come off from the outside by first removing that screw on the outer tubing at the body end or do you remove the end panel first?

Brian

[nelson]

Last weekend i did a test with vallon, that show it can detect this two tiny copper wires, the smallest one at 1 1/2 inch, the second one at 3 1/2 inches. Very good.

[Ferric Toes]

The Full Kit

Well almost the full kit, as I have a few other ideas to investigate.
All I need now is an unthrashed area with lots of buried treasure. Nuggets, rings, coins or Spanish gold will do.

Eric.

[Ferric Toes]

Hi Eric,

Having removed the threaded collar and end guide assembly, I now understand what you have been talking about.
What I have noticed is that most of the design is symmetrical which means the arm rest has identical holes on the opposite side to the holes where the black coil cable rod passes through.
The end guide (attached pics for those interested) is only machined on one side to take the black cable rod, however, there is plenty of room to machine an exact copy on the other side.
[ATTACH]39788[/ATTACH][ATTACH]39789[/ATTACH]
The idea then, is to get rid of the existing audio /data connector and run the audio cable from inside the electronics housing up through another rod and into the modified end guide.
I think the best thing to do is machine complete new end guide that matches the exiting for fitment but will be wide enough and deep enough to accommodate a 6mm jack socket and wireless module + support power.
I have some delrin laying around that will fit the bill nicely.

Will post up some CAD drawings once I figure it out.
Now to see if I can open the main housing without damage

Brian

Be careful, as the end cap of the main box is not symmetrical. The coil cable goes in via the hole on the left in the front view. You can see a fibre washer and under that is an O ring. The black aluminium tube screws down on this to make a watertight seal. You will see spanner flats at the other end of the tube. Notice that the bottom edge of the cap steps down a bit; so now look at the inside view. The molding is full thickness where the cable comes through, to accommodate the seal and the threaded section to screw in the tube.
You cannot have a similar tube screw into the other side (left) as there is not enough thickness and the hole cannot be on the same level which is right on the inner lip of the end cap.

Eric.

[Mdtoday]

Hi Eric,

Having removed the threaded collar and end guide assembly, I now understand what you have been talking about.
What I have noticed is that most of the design is symmetrical which means the arm rest has identical holes on the opposite side to the holes where the black coil cable rod passes through.
The end guide (attached pics for those interested) is only machined on one side to take the black cable rod, however, there is plenty of room to machine an exact copy on the other side.

The idea then, is to get rid of the existing audio /data connector and run the audio cable from inside the electronics housing up through another rod and into the modified end guide.
I think the best thing to do is machine complete new end guide that matches the exiting for fitment but will be wide enough and deep enough to accommodate a 6mm jack socket and wireless module + support power.
I have some delrin laying around that will fit the bill nicely.

Will post up some CAD drawings once I figure it out.
Now to see if I can open the main housing without damage

Brian

[Mdtoday]

Hi Eric,

OK thanks for that, I will look at the post.
If the coil cable runs right to the battery cap area, then I will revert back to either machining a light-weight cover, or a vacuum mold to fit the full length of the under side of the body.
The arm cradle will also be modified and stay fixed at the battery cap end
I don't like exposed cables so your idea on the audio cable is great.

Brian

[Ferric Toes]

made up a little board with Eric's audio transformer mod. See pic
I was about to machine a cover to to fit on both under sides of the Vallon body to give more options to route cable but it may not be required.
Eric, does removing the single grub screw on the end near battery cap release that part?
I'm thinking of putting the cable through as you have one but retain coil cable in shaft
[ATTACH]39786[/ATTACH]

Brian

You need to do steps 1 - 5 on post 649 to remove the rear support. How are you planning to deal with the coil cable which at present runs through the black tube?

Eric.

[Mdtoday]

made up a little board with Eric's audio transformer mod. See pic
I was about to machine a cover to to fit on both under sides of the Vallon body to give more options to route cable but it may not be required.
Eric, does removing the single grub screw on the end near battery cap release that part?
I'm thinking of putting the cable through as you have one but retain coil cable in shaft


Brian

[Mdtoday]

Great work Eric!

Brian

[mschmahl]

Great work Eric! This s a nice solution.