Jeohunter - Visual Ground Scanner

[Funfinder]

Workaround update and precautions!

Hi geo-i

thx for your kind words and that you you're so tough in
such a frustrating situation. Also my respect that you
wanna try to repair it and I have a good feeling that
you could make the Jeohunter work again.

And Thank you bro for the new very good makro pictures!



Before you start some additional precautions:



- if you think the soldering pins are to tiny
for you better find some with good soldering skills!
(or buy a soldering iron with a very small tip)

But if you work cautious by the method I have
described (soldering tin only at the wire-contacts,
holding wire onto the marked point and heat wire with
soldering iron until metal melts and creates connection)
you should have no problems.


- be very careful at the C4 spot (see picture - dot of the "!")
here you must try to solder as short as possible
because otherwise to much heat will destroy the C4
(this is a very small capacitor, surface mount device and
we don't have the value, so we can't replace it)
But the marked spot for soldering at the left side of C4
is pretty "large" so you should make it.
Just try to solder as short as possible at this location!



- you can find the replacement resistors in old
electronic stuff like broken TVs, VCRs, radios etc.
All you need is a pliers to break them carefully off
(plug of mains and be careful if you disassemble TVs,
those can contain loaded high voltage capacitors...)

The color codes of the needed resistors are:
--------------------------------------------------
51k resistor: green-brown-orange-gold (or silver)
(or gold-orange-brown-green if you hold it reversed)

5.1k resistor: green-brown-red-gold (or silver instead of gold)
(or gold-red-brown-green if you hold it reversed)

If you don't find them you could try to use a resistor
that is very close to the given values:
for the 51k R. from 45k to 55k)
for the 5.1k R. from 4.5k to 5.5k)

pleas google for resistor color codes and how to use them.

- try to clean or carefully remove the burned area
of U1 to avoid shortcuts form there
but I hope it will work without it, because
if the IC is burned there is no more dangerous
connection inside of this digital potentiometer
(a potentiometer is just a variable resistor)


! geo-i, perhaps you can call yourself really lucky
that only replacable parts got burned!
Let's hope nothing else has been damaged!
If nothing else was destroyed the chances are
really good that our workaround will work!

But this time you really have to do it PERFECT !!!
Good luck and take good care!

[geo-i]

for all answer

hello sir Qiaozhi each human being had made a mistake i am responible for the all answer i will try to change my mistake sir thanks.



regards
geo-i

[geo-i]

thanks you my friend

hello my friend fun finder thanks you so much again
you are the friend i will try to very carefully the best
i can thanks for all my friend.


regards
geo-i

[geo-i]

some brown

hello my best friend fun finder this are
the picture that some brown burned stuff
that i see with the special lenz.


regards
geo-i

[Funfinder]

geo-i

listen very carefully:

I found out an unrisky and possible workaround.

BUT:

You have to work extremly carefully, you should
get some experience first in soldering extremly
small contacts and it's fully your own risk. But
because now the damage already is done you
have not much to risk anyway!

What you have to do is to solder 4 isolated wires
to the shown contacts. At the end of the left 2 wires
solder a 51kOhm resistor and the both ends of the
right 2 wires (those are near the U1 chip) will
became the "variable resistor" area.

The wires are important because for testing you have
to reattach the vertical board and after this you don't
have any access to the below area.

For the resistor test wires to the right on the picture:
In the beginning you will start with a very high
resistor (100kOhm) to find out the effect.
Perhaps nothing will happen, so you can try a
lower one (50k) and test again.


How can you solder such tiny contacts?

You have to use very thin isolated wires.

Now solder a small amount of soldering-tin
to the contacts of those wires.

Press the tinned tip of the wire exactly over
the soldering pin and heat it from above
carefully until the wire is soldered onto the pin!

Try and repeat this technique first at a test
board until you have enough expierence.


For the moment this is your only chance if you
don't wanna send the mainboard to Makro Group!


Describtion of this workaround:

Usual the digital potentiometer will create a
variable resistor output between the pins 2 (LB)
and 4 (WB). But because you have told me this
IC was burned there is no longer any current
flow or resistor activity!

At the moment Pin 2 and Pin4 are cutted off
and that's the big problem.

By the way your crazy screen indicates that
before this IC was still functioning but already very bad.

Anyway - if you bridge Pin2 and Pin4 with your own
resistor, you can re-activate the needed connection.

But this has to be done very carefully!
You have to make shure that the end of the wires
will create no shortcut! Isolate them if you don't
use them for tests!

You should use ca. 20cm long wires for the
workaround connection so those are long enough
after you have plugged everything as it was before.

And as I have told already:
First go shure your accu-pack works correct.


You have nothing to lose! At the moment the board
doesn't work and it makes no big difference if there's
one malfunction or another one additional if it comes
to replacement.

But what you can gain:
- saving ALOT of money and time
- having the great feeling that YOU could "repair" it
- getting experience in electronics

Best wishes and good success!

[Funfinder]

@ geo-i

Looks like your later accu-pack wiring
has destroyed parts of the power circuit.


Before you do anything further you have
to be 100% shure that your accu-pack
really has 14,8V and correct polarity!


Your picture is OK but very hard to see -
seems R24 was burned and U1 5403 EUB.

R24 is replaceable if you are very careful
with a small 51kOhm resistor but the U1
which seems to controls the LCD screen:

http://www.digchip.com/datasheets/parts/datasheet/280/MAX5403EUB.php

will be a problem.

Perhaps there is a simple bypass possibility
so you will have a fixed screen brightness...

Are you really shure that U1 has been damaged?
Can you recognize some brown, burned stuff there?


> i am quite confuse about the connection

If so please ask before - the diagram is really clear.
the both "power-line"-pins are connected together by
an orange cable. However it is very simple to solder
the cable to the correct pins - which you have done well.

Good luck, geo-i, if we're lucky we'll find a workaround.

If it's the U1 we need the pin-outs of this IC and
have to find out how exactly it functions.



@ Qiaozhi
I guess there was no more guarantee and geo-i
thought "no risk, no fun". Perhaps the price for learning
now is high but perhaps we will have a chance to repair
this "perfection in it's nature" detector.

Shure, the missing special reset button at the older
models is a problem, but the new ones have it by default.

[Qiaozhi]

What amazes me is why someone would spend 2500 euros on a detector that, according to the advertising is "perfection in its nature", and then frig around with the innards when they don't really know what they're doing.
That's certainly one way that's going to make the guarantee null and void.

[geo-i]

direct soldering

hello my friend according to the picture diagram shown i am quite confuse
about the connection whether both of the 2 cabel orenge and black is been connected together see the picture.thanks




regards
geo-i

[geo-i]

correction of circuit

hello my best friend in your question there is a many answers
yes i switched off the power fist and remove all the accu pack
and i remembered last week when i build the joehunters accu
pack with the ultrafire i discover di scomfort smell burned in the
box of joehunters i quickly pull out the accu pack switch and
removed all cabel . after that incident i did not use the device
for one day and decided to build new joehunters accu pack
but with different case it can remove easily i waited for 7 hours ,
after i saw your modification reset button i am i feel more interest
to make one but i was doing it wrongly due to the circuit is not clearly
shown . i only decided the ciruit got burning smell shown in 2 red circle. thanks


regards

geo-i

[Funfinder]

Hi geo-i,

why you started with this Reset-Button-Mod without
informing me and using the great chance of direct help?
Because this was the first mistake.

And what was (the second) your big mistake?
Are you shure that you made a big mistake?

Perhaps this is also a problem if you translate all this
information by a computer and this computer-program
tells you wrong things. How good is your english?

I'm asking this because of the question:
Of exactly what circuit do you want a picture?

After the new drawn Jeohunter Connection Layout
everything should be pretty clear.

Please geo-i, tell me exactly what has happened
and what is the actual status quo, this means what
is the situation now with the Jeohunter.


As example: How did you connect the cables?


If you have problems to describe it take some pictures.
Show me pictures so I can compare it and see the
difference.

I'm feeling with you in this sad hours of possible loss
but you have to look forward!

First we have to find out if there is really nothing to do
and next you may perhaps have to find a way for a
replacement of the maybe fried or burned parts.


But you have to help and if you ignore all my formerly
questions for information etc. we won't come any further.
Do you understand this?

[geo-i]

mistake

hello my friend because the picture is not very clear
bro i am making big mistake sorry my friend can you
give me the picture of the circut from the front
side thanks.



regards
geo-i

[Funfinder]

Jeohunter Connection Layout

Hi geo-i,

hope the especially drawn 4 U schematic helps.

You must control that every cable of the
vertically pcb leads to the correct plug.

Check out first if you have the same mainboard
as shown below (the lower right region contains
the transmitter/receiver & detection circuit and
is usually hidden below an alu-housing so only
compare the rest of the board if it is identical).

Be very careful about the 2 black/red wired cables -
don't confuse them - one contains the full 14.8v.

Always draw a little schematic of the
correct wiring before you remove cables!

Check out that the cables really lead to the
correct plugs like you can see in the layout
and that the plugs have a good connection.

Make shure the color of the wires finally
will have the same position as shown!

Good Luck!

[Funfinder]

direct soldering!

geo-i, your DSC00660.JPG shows me that you have
removed the vertically printed circuit board. Why?

This board holds the on-off switch which is very
dangerous if the accu-pack was still attached!


This whole vertical circuit board removement
was not as described by me (see below),
because you can simply solder the both wires
easily without removing that PCB and
without creating possible troubles.

Because the both needed contacts are directly at the
opposite side of the upper flat-ribbon cable.

I hope nothing serious has happened at this action.

[Funfinder]

Hi geo-i,

this window screen is crazy!

Do you have really had connected the
coil-cable while shooting this first picture?


I really have no idea what's been happened,
but the Reset Button Mod cannot be the fault,
because even if you had created a shortcut this
only would have the same effect as if someone
presses all the time the touchpad reset button
while turning the off Jeohunter to on.


So there must be a different cause!

Perhaps while opening the box you have
created some loose-connection at one of
the plugs. Check out the 2 plugs with the
colored monitor wires in the back of the box.

Try to remember exactly what you have done
after opening the box.

- Have you switched off the power first
as I've told or removed the accu-pack?

- Was there a smell of any burned?

- Have you removed a cable and forgotten
to plug it back?

- Have you touched a part of the mainboard
by some piece of iron, wire etc.?

- Have you done the above described 4 step test?

- is the reset-button cable still there or removed?


I need answers to all of those questions
if we should have a chance to find out
what has happened. And if you may have
made a mistake you know about please tell it.

At the moment I can't make any predictions
if your Jeohunter is somehow broken or not.
It may be only some kind of plug problems.

It would be fine if you could make some
detailed pictures of the opened Jeohunter.
Let's hope the best for the moment.


PS: Yes, you have the identical touchpad -
it can be seen at your picture from here:

http://www.geotech1.com/forums/showpost.php?p=142775&postcount=466

[geo-i]

window screen joehunters

hello my friend fun finder thank every thing but i have a big problem
i am worry about my joehunters the screen does not produce
proper way and the picture do not stable no sound got out
it like dizziness please help me bro SOS
this are the picture of '' window screen goes like crazy''