Compadre Schematics

[bklein]

My unit does not have a drain wire. There are just two twisted pair wires coming out of the cable, going to the pcb. On Esteban's post #3 with the photos of the board etc. you can see the coil wires attached on the underside at the left. No separate ground wire but one of each pair likely connects to ground on the board. The Compadre coil is fixed connection but there is an alternate they offered to sell me that would have to be wired in.

Barry

[simonbaker]

oh, and are you sure about the drain wire? There is none on mine.
Just two twisted pair wires connecting to the pcb.

I recall my Compadre (5 1/4 " coil, new model) does not have outer shield connected, only two pairs of wires. I was surprised.


-SB

[Merc]

I don't have a Compadre so I can't be 100% sure. I have 4 other Tesoros that all have shielded cable with a drain wire. It's just hard to believe that Tesoro would use a different type cable on just one model. The ones that I have all have coil connectors so you can change out coils. Isn't the Compadre coil cable soldered straight to the board?

Merc

[bklein]

Yes. It is a shielded cable and the shield drain wire should be connected in the connector housing.

Merc

oh, and are you sure about the drain wire? There is none on mine.
Just two twisted pair wires connecting to the pcb.

[bklein]

Does your detector have this characteristic - beeping if you twist the coax slightly at the coil input? It may be due to some wires just simply moving or it may be due to a poor connection. Is this connection accessible if I take the coil cover off?

[Merc]

Yes. It is a shielded cable and the shield drain wire should be connected in the connector housing.

Merc

[bklein]

Has anyone taken this Amigo schematic and verified it against the Compadre and re-numerated the various components to correspond?
It is pretty aggravating trying to match it up as is.

My unit continues to randomly beep. It seems it does this if in the constant presence of metal or wetness of the soil. I see this coming from the outputs of the 393 comparators. This circuit looks kinda weird to me.
To work it gets a pulse on the lower comparator and a delayed one on the upper. R18 sets the delay timing of the upper one. The Q3 circuit sets a fixed bias for the threshold. Part of my unit's problem must be here somewhere. So I need to find the Q27 circuit and Q3 circuit and check them out. Weird how on my unit, only the VR4 trimmer seems to do something. Too far to the left and it beeps all the time, back off to the right and play with ground balance of the unit and it seems ok. But the others don't seem to change the way my unit works. How about you guys?

But I notice that if I (lightly) twist the cable going into the coil (remove/unscrew the connection cover) it beeps with movement. Does this coil have a shield that may be not making contact inside?

[Merc]

I had a problem my Golden Sabre(original factory built) beeping randomly when I would flex the coil cable where it entered the connector housing. I opened it up expecting to find a broken wire but there wasn't one. Looking close, however, there was an extra unused black wire in the cable and it looked like the strands of wire at the end were touching one of the receive coil wires. I cut the cable off and resoldered all connections and taped back the extra wire. I also connected the shield drain wire to the tab connected to the body of the connector. It only went to the middle pin of the connector before. Problem solved. No more beeping when I flexed the cable.

Merc

[simonbaker]

I'd say it picks up:
Penny 6 1/2"
dime 5 3/4"
quarter 7"

But... it beeps at a repetitive rate once it gets a hit or gets hit.
I opened the circuit board area up and just moving the coil wires a tiny bit
makes it sound. But it may be reacting to all the metal where I am.
I have a scope etc. and I think I'll try my way through the schematic to see if I can pin this down. Pretty weird that Tesoro thinks it is fine.
Maybe they use headphones and I'm not....
Maybe they use a different power source....
That is one thing. Originally I had a low battery and didn't know it.
Now with a new one it comes on with a real long beeeeeeeeeeep.
Annoying for sure. Didn't know that the beep at the beginning is a battery indicator.

I tend to agree with you that it doesn't seem quite right. Repetitive beeps are definitely not normal.

I have found with TGSL circuit (probably similar to Compadre) that sometimes while playing with the circuit, I get a situation where the speaker (or headphone) beep seems to cause a dip in the rail voltages which appears in the outputs of some op amps, and causing repetitive beeps. I'm not sure what sets that up exactly -- but you could check your V+, V--, and ground traces (rails) to see if that happens. Then make sure the voltage regulator chip is good; consider adding extra power supply filter capacitors or replacing the originals.

I find it very hard to diagnose exactly what causes these problems - often the signals look fine on the oscilloscope. But it is still worth checking the phases of the signals feeding into the Synchronous Detector to make sure they look right and that the discrimination knob moves the phase of it's driver signal appropriately. This could be tricky to know without having an additional perfect Compadre to compare with and excellent familiarity with the circuit.

Do you have a schematic for your model?

Touching wires with fingers could trigger beep for many reasons. Try jiggling them with a long wood stick instead.

At least your battery check is working fine and dandy!

Regards,

-SB

[bklein]

I'd say it picks up:
Penny 6 1/2"
dime 5 3/4"
quarter 7"

But... it beeps at a repetitive rate once it gets a hit or gets hit.
I opened the circuit board area up and just moving the coil wires a tiny bit
makes it sound. But it may be reacting to all the metal where I am.
I have a scope etc. and I think I'll try my way through the schematic to see if I can pin this down. Pretty weird that Tesoro thinks it is fine.
Maybe they use headphones and I'm not....
Maybe they use a different power source....
That is one thing. Originally I had a low battery and didn't know it.
Now with a new one it comes on with a real long beeeeeeeeeeep.
Annoying for sure. Didn't know that the beep at the beginning is a battery indicator.

[simonbaker]

Mine has the 7" coil.
Just got it back from Tesoro today in fact. They said they set the sensitivity back higher. Could be - I'll test it tomorrow. Looks like they may have even just put a new coil on it! It still will beep if I bump the coil. Is this common? I understand how the cable can be microphonic and cause this but I don't think that is what is happening....

It depends on how hard the "bump" is. My newer Compadre (with 5.75" non-removable coil") doesn't beep with casual bumps. But it is not a very deep detector also.

I would be glad to have beeps when bumped if it meant more depth and sensitivity. Can you do some air tests with common coins for us?

Still, if it beeps at the very slightest bump, that seems unusual. If it beeps just by sweeping in the air fast, I would say there is something not right.

I would think having Tesoro look at it is about as good as it gets -- not sure anyone here can help more. Of course if you are a tinkerer at heart and don't mind sacrificing the machine, you could start opening things and checking with oscilloscope, etc.

Is the cable really secure against movement? If not, tape it down and check again.

Regards,

-SB

[bklein]

Mine has the 7" coil.
Just got it back from Tesoro today in fact. They said they set the sensitivity back higher. Could be - I'll test it tomorrow. Looks like they may have even just put a new coil on it! It still will beep if I bump the coil. Is this common? I understand how the cable can be microphonic and cause this but I don't think that is what is happening....

[simonbaker]

I know there seems to be a problem with the connection but that alone may not be enough to explain the behavior. The coil is unique to this detector and local dealers do not stock this model or coil. And if it is the coil I would just have to buy another - like Tesoro suggests. I am more interested to know what in the coil could cause this and how to fix it. Does the lower cover slip off with force and then make the insides accessible or is everything covered in epoxy or some goop?

What model Compadre do you have, the older one with 7" coil, or newer one with 5.75" coil? (I saw some ad for a "new" one with 8" coil, but not sure it's real).

-SB

[bklein]

I know there seems to be a problem with the connection but that alone may not be enough to explain the behavior. The coil is unique to this detector and local dealers do not stock this model or coil. And if it is the coil I would just have to buy another - like Tesoro suggests. I am more interested to know what in the coil could cause this and how to fix it. Does the lower cover slip off with force and then make the insides accessible or is everything covered in epoxy or some goop?

[Qiaozhi]

Hi guys,
I recently bought a used Compadre. I was amazed really at its detection abilities compared to other generic detectors I have had. But it had a problem in that it beeped at the ends of abrupt sweeps. This was not due to the cable moving in the detection area. I could just lightly bump the coil with the palm of my hand and it would sound. So I sent the unit in to Tesoro. I got it back with a note saying the battery was bad and to install a new one and that they found the sensitivity was too high. ARrrgh. With a new battery it constantly beeped at the no disc. setting and was not as sensitive as original. And it still was sensitive to mild shock. I called them and was told that the coil was likely the culprit and that they had a better one they could offer. As the beeping at no disc. is not normal and was not there before I sent the unit back to them and am awaiting their call, hoping they find something this time. Any of you experience this sensitivity to mild shock? Anyone ever take the coil apart - I wonder what could be moving in there. I found that if I just slightly rotate the cable coming into the coil (black connector housing slid back) it would sound. So maybe a bad connection there. But how to fix? I'm hoping they fix it this time but if not I'd like to give it a go myself and am open to suggestions. They do actually kind of discuss this behavior in the manual. But I have never experienced this with other detectors and think it abnormally sensitive to it on this one.

The easiest way to isolate the fault would be to try it with another coil. You could take it to your local metal detector shop for testing. They should be happy to assist you, especially if they think you might purchase a coil from them.