Goldscan 5 damaged:sadwalk:

[Draco]

Hi all, I just fail Goldscan May, somewhere in Europe where you can fix?.
When I turn, humbral goes crazy, suddenly sounding serious and increases the volume as if it were detecting a ferrous metal. It has been stored in a closet with the battery disconnected. No has pododo occur. Always well treated. Someone has this ever happened?

Sorry for my bad English, I use online translator.

Thank you.

Hola a todos, mi Goldscan 5 acaba de averiarse, alg

 

[Draco]

YouTube video of the problem. Thanks for looking.


[video]http://youtu.be/Y3P7w9pIdqw[/video]

 

[Draco]

n/t

 

[Reg]

Hi Draco,

Has anyone tried to adjust any of the controls on the pc board? There is one that might cause this. You might try passing your ring very close to the coil and see if the audio does go back to the low threshold setting. If a stong signal works then the setting might be the problem or part of the problem. So, try a strong signal from your ring passing very close to the coil and see if things reset ok.

If the audio doesn't reset, then when a very strong response happens does the lingering audio remain much stronger? If it does, then it sort of points to a certain part of the circuitry.

What is happening is probably the result of one of the circuits not resetting. The logical one is the second filter which has a long time constant. There is an added capacitor than can be jumpered if it is the problem but a picture of the pc board will be needed to see if it is an add on or has been installed on the pc board on a later version. The area that has to be looked at is under the upper audio board.

Working on the GS 5 is difficult and taking the main board out is a challenge.

Good luck finding someone to work on your detector.

Reg

 

[Draco]

Thanks for answering Reg. The Gs5 never been adjusted, or tampered with since I have it. That the previous owner was sent to Eric Foster, to update it, not any more ...

It's the first time I open it this way. I saw that in the small plate, there is like a loose bridge.

I tried what you mentioned, but still the same.

Thanks again

Gracias por contestar Reg. El Gs5 nunca ha sido ajustado, ni manipulado desde que yo lo tengo. Se que el anterior due

 

[Reg]

Hi Draco,

When looking inside the detector box with the coil lead to the left you can see most of the layout of the lower board, but not all.

There are two pc boards, the larger lower one is the main lower pc board and sitting above the main board at the right end is the smaller audio board located above the larger one. The two white standoffs that look something like knobs, with one on each end hold the small board in place. Unscrew these two standoffs and carefully lift the small board and sort of fold it back so you can take pictures of the parts below it.

I need to see the lower board. The upper end of your present pics is the area of interest. I use a spring loaded clothes pin to hold the board back when taking pics. Other types of spring clamps can be used to hold the smaller board back as long as they are not so strong that they would break parts.

Below the audio board at the upper end you will see wheresome parts were added. I need a close up picture of those parts. So, you may have to move some wiring out of the way a little also. Look those parts over closely and see if one of the wires has come loose.

Let me know what you find. Also, take pics of the lower board below the upper one while concentrating on the upper end of the lower board.

Reg

 

[Reg]

Hi All GS 5 owners,

The pics posted by Draco show quite a few small blue pots located on both boards. Whatever you do, DO NOT ADJUST ANY OF THEM. There is no pot inside that will enhance the sensitivity or reduce noise. Instead, each pot has to be calibrated using special test equipment and special test procedures to properly align the detector. All of these pots have to be properly aligned for maximum depth.

Some adjustments require a scope to make the adjustment while others can be done with a high end digital voltmeter that allows accurate readings down to 1 mv. So, don't try to mark the pots and hope to get them back to the right position because it won't work.

Even the slightest wrong adjustment can and will result in loss of depth at best to the worst which is stopping the detector from working at all.

Reg

 

[Reg]

What I hope to see under the audio board is some added parts that have been added to the main board. Hopefully, one of those parts has come unsoldered and causing the problem. Also, if the parts are positioned correctly, a small jumper can be added to eliminate this addition as the possible problem.

Unfortunately, the GS 5 has had several modifications in its evolution and one of which included redesigning the pc board and installing these parts properly. So, depending upon the board itself, the parts can be either sitting on top of the board as an addition or installed because of a board change. If added on top, there is a slight possibility that one of the parts has come loose.

If there are parts on top, there will be three parts involved, a .47 uf cap, a 5.6 meg resistor and a FET. I am hoping the ground end of the resistor came loose and that is causing the audio to wander. If this is the case, then a simple solution would be to jumper the cap to eliminate the problem for good.

This special parts addition was installed to eliminate drift of the threshold. However the use of special parts that don't drift eliminated the need for this mod. Also, the main drift problem was determined to be primarily caused by something else. So, the removal of this addition will not cause any problems but might eliminate some.

Reg

 

[Draco]

Thanks Reg, I hope I understand your question.

 

[Reg]

Hi Draco,

I need a picture of the lower board but it has to be larger. Your pictures are too small for me to determine anything. Please make your pictures larger and give me three or so of the general area of the lower board.

Thanks,

Reg

 

[Reg]

Draco,

Also, turn off the ground balance and check to see if the signal still varies or acts normal with the GB off.

Reg

 

[Draco]

Codigo THUMBNAIL HTML:
http://subefotos.com/ver/?5969a22ddd4d5920101f596bde678930o.jpg
http://subefotos.com/ver/?d063acf10471615f63292dfa5239d272o.jpg

Hi Reg, I hope you can see them well now. The forum not allowed to expand the images.
Click on the link and then click on the photo, will be much larger.

The problem persists in both straight Pi, as in ground balance.


Thanks for your patience.

 

[Reg]

Hi Draco,

Now, when you get time try using a high conductor object instead of your ring and see if a low tone causes the same signal wandering once the target is removed.

I don't see the additional circuitry that might cause the problem, so your unit must be a little older one, and the problem is somewhere else from what I was hoping.

Does turning back the gain control reduce the wandering signal?

What happens to the audio signal if you place an object near the coil? It should start strong if the object close to the coil, but then fairly quickly reduce in audio to the threshold level. Does it do this?

Finally, if you turn the unit on and just let it set, does the signal begin to wander or does it require you pass over a target before it starts?

Reg

 

[Reg]

Draco,

You flipped a toggle switch down on the side of the GS 5 in your video. What does that toggle switch do? I don't have a GS 5 now to look at and I couldn't read what it said above that toggle switch.

Thanks,

Reg

 

[Draco]

Hi Reg, so does the problem when I turn it on and not any objective way. The video did so, you could see every possible way, both Pi so straight, as in ground balance.
When high objet spent a driver, does not return to normal background tone.

If I put an object near the coil, low audio signal humbral level, but with strong ups and downs, as heard in the video ..

I will make another video if you feel it necessary.

Ps: In the video, active ground lever balance

Tank you

 

[Reg]

Hi Draco,

When I ask a question the answer will help me determine what might be wrong. That is why I ask them.

For example, when you wave a high conductor and the tone goes low, what happens. I don't care what the tone is doing once it takes off because strange things can happen.

What happens when you turn the gain down? Does it get worse or better?

When you look inside close to the center of the main lower board, some of the GS 5's have a jumper across two points that say switch. Close to this jumper is another point with a G. The G stands for ground. The Jumper at the location where it says switch is a test setup that can be used to align the detector. What it will do is effectively short out the signals coming from the coil and early circuitry.

On other GS 5's, there are two pins instead of a jumper and those pins have a small black shorting plug placed on the pins. Please look and see which you setup have. You may want to take a pic of the center of the board but make sure it is wide enough because the area I am talking about is a little to one side which would be the high side in your pics.

I am hoping you have the shorting plug. If you do, I will ask you to pull the black plug off and see if the audio still changes if you let it set for a while.

I have attached two different pics, one showing the black shorting plug and the other showing the jumper on the pc board. Hopefully, from the two pics you can find the same location on your detector to see if you have the black shorting plug or the jumper

The two pics are taken looking at the same place but from the opposite side of the board. That is why they don't appear identical. They are looking at the same point and each has a red arrow pointing to the area of concern.

If you have the black shorting plug, let me know and we will have you remove that shorting plug and see if the audio wanders or not. Removing this shorting plug will not harm the detector but it will or should make the detector fail to detect anything and have a nice solid non changing hum. If this eliminates the audio changing, then the problem is before or at the shorting plug.

Do you have any test equipment?

Reg

 

[Draco]

Hi Reg, sometimes the problem is the online translator.
I have taken several photos from different angles, so you can see nice pictures. I have found no bridge pins.

Whether you are in PI mode rectum as ground balance mode. After switching on, the threshold tone changes, is heard as if a tall object detecting driver and when I pass the ring near the coil is detected, but a bit away, about a vacuum threshold tone. Do not know how to explain better.

After removing the wires to take the pictures, looks better, but not like before.

Hope this helps, I have explained.

Thank you again.

http://subefotos.com/ver/?2208990a252765668dff7d71627d106bo.jpg
http://subefotos.com/ver/?1d84ec8a91abcc2ba7971ab4ae9b3e3co.jpg
http://subefotos.com/ver/?e005357b268fe83d084fd4ebb5b26714o.jpg
http://subefotos.com/ver/?640a9fb6a3ad8e76f3b83afeaebb038co.jpg

 

[Reg]

Hi Draco,

I am certain the three wires I asked about go to the GB switch. Let me know if this is true.

Now, before going any farther, what happened before you began having trouble with your GS 5? Did you let it sit for a long time? Did you drop the detector or bump it hard? Was there something else that might have caused the problem?

The reason I ask is to try to determine what the problem might be. If a detector sits for a long time and isn't used, sometimes one of the capacitors can fail. Dropping the detector may cause one of the small internal pots to break. Severe static might cause one of the internal components to fail. Then there is the nature failure of a part.

So, there are lots of different reasons why a detector fails. It helps to know just what happened to cause the failure if there is a reason such as dropping the detector.

Fortunately, the operational amplifiers are all in sockets so if one of those fail, they can be easily replaced without having to take the detector all apart. Unfortunately, lets hope you don't have to change one because some of them require special equipment to calibrate the detector once certain amplifiers are changed.

Do you work on metal detectors? Do you have test equipment or have a friend who has test equipment that can work on them? Answers to these questions can help find someone who might be able to fix the detector so you don't have to spend excessive money sending it somewhere.

Getting back to the GB circuitry, I consider this part of the detector about the half way point in the design. So, if we can determine whether the problem is before this point or after this point will help in determining just where to look for the problem.

Finally, I hope you don't mind all the questions. It is my way of helping you to determine what might be wrong and where to look for the problem.

Reg

 

[Draco]

Hi Reg, I do not mind if I do all the questions it considers necessary, is an honor.

The detector was kept for some time, never received any blow.
I do not work in metal detectors, although I have done some out of a technology forum. I have no computer, but my brother if you ask to see.

The problem is in any position of the GB and regular PI mode. After removing the cables to take pictures, it seems that the GS5 is better, but not like before. Now is more sensitive to the low drivers, but less high. The potentiometer on and setting of treshold, before damage, it was a little to the left of center, to hear a buzz and now I have to put a little to the right of center. The threshold before and now was soft chirps. If under the range, then I can put treshold adjustment to the left of the center and be heard ringing becomes soft.

Thanks for helping.

 

[Draco]

The Goldscan already been fixed, thanks to the invaluable help of Reg

Thank you very much friend.