Troy X3 problem

[m23585]

I thought that maybe better I will put this here. So, after playing with pcb a bit, my Troy X3 is not reacting to metal. After plugging original coil, when I start it, it makes one longer beep (normally is one short) and there is no reaction to metal. Pinpoint button also not working, battery check works ok. I checked all the wires coming from pcb to the plug and looks like all wires are ok. I'm 90% sure I have not done accidental shorts on the pcb and 99% sure no mechanical damage to any of the components. Any ideas what could cause the problem? Thanks

Greg

[ivconic]

TX is working?
You can scope it and see.

[kt315]

do you check a speaker? have you connect another speaker and check with it?

[ivconic]

KT315 you must be joking, man is hearing the sound; so speaker is alright.
If he hears long sound after switching On and later there is no detection; than one of the possibilities can be TX failure, due various reasons.
So i would focus my attention first on TX and later on other things.
Look the photo and check if there is TX signal at all.
(btw if you played with those trimmers ... well... )
Or maybe you switched the trimmers and put one on wrong place?
You didn't provide us with enough informations about your "playing" with pcb... as you mentioned.
Give us more "fabric" so we can form some sort of analytic thinking here... man!

[ivconic]

Trimmer 100k (on schematic) must be precisely adjusted to noted default.
Otherwise you can push it "out of band" and choke the oscillator way out of the defined resonance.
I don't know what have you done, i can only assume, so now i am assuming that you wanted to trace pcb and you maybe removed some components from the board.
Later when returning them back to board; i assume that you mixed up some trimmers, components or something like that.
Assumptions like this one can look pretty funny in case you didn't done something like that.
But you said: "after playing with pcb"... and that gives me quite "picture" of what you could do with it!
When i "play" with my pcb's that usually leads to "greenfield pcb" ... or 5kg hammer(ed) pcb at the end!
Sch:

[kt315]

a time to play...to draw a schematic. in this time the forum will get good schematic or there will be only again and again insinuations. that is the question!

[m23585]

I will try to explain what I did, so you may have better idea about this. I built a 2D coil for this detector but I stuck at the stage of nulling. I soldered Tx wires (of that homemade coil) to coil cable I have, and that cable to the pcb on the components side (will do picture later). After that I tried to arrange loops to find low residual voltage in Rx. With no success, I decided to connect Rx to pcb as well. When I did it, I checked how detector responded to a coin. It was working ok but depth wasn't great. So, I decided to de-solder that Tx and Rx wires from pcb and put detector back together. When finished, I plugged original Troy coil to it and noticed what I described in first post. Now, there is a small chance I could do short circuit in that area where I soldered Tx and Rx wires to. Also, I'm not so sure about wires coming out from pcb to the plug. Because they are a bit twisted and maybe one of them is broken? But I checked connectivity from one end to other and they seems to be ok. Speaker does work and original coil too, no doubts about it. Hopefully this helps. Thanks in advance for any inputs. Will get back to you after work. Cheers

[ivconic]

I will try to explain what I did, so you may have better idea about this. I built a 2D coil for this detector but I stuck at the stage of nulling. I soldered Tx wires (of that homemade coil) to coil cable I have, and that cable to the pcb on the components side (will do picture later). After that I tried to arrange loops to find low residual voltage in Rx. With no success, I decided to connect Rx to pcb as well. When I did it, I checked how detector responded to a coin. It was working ok but depth wasn't great. So, I decided to de-solder that Tx and Rx wires from pcb and put detector back together. When finished, I plugged original Troy coil to it and noticed what I described in first post. Now, there is a small chance I could do short circuit in that area where I soldered Tx and Rx wires to. Also, I'm not so sure about wires coming out from pcb to the plug. Because they are a bit twisted and maybe one of them is broken? But I checked connectivity from one end to other and they seems to be ok. Speaker does work and original coil too, no doubts about it. Hopefully this helps. Thanks in advance for any inputs.

Ah so!
Than you have nothing to worry about: you just mixed up the wires.
We will fix it here, no problem.
First take ohmeter and distinguish which pin on plug is for what. Define which pins are for TX and which are for RX. This of course with coil connector plugged into plug.
Let me see through my documentation if i can find my drawings to make your job easier...

[m23585]

No, no ivconic. I didn't remove original cables from pcb.

[ivconic]

No, no ivconic. I didn't remove original cables from pcb.

I saw this : "...So, I decided to de-solder that Tx and Rx wires from pcb and put detector back together..."

Anyway here is the skim drawing i did just moment ago, so you can compare it with present situation on your device:

[ivconic]

Maybe you shorted some traces... maybe you made some breaks in traces...
In case you shorted TX traces there is a chance that you burned TX...
And that returns us to the beginning: the TX.
Check it! Just check it's functioning first.

[ivconic]

Here is the pin assignments for TX transistor (which may be burned, worst scenario).
In case it is dead (wish you not) than you can temporary replace it with 2N2907 or BC327/40 (i tried those and are working fine).
How to distinguish if TX is working?
Simplest possible is to use scope and check for signal on collector.

[m23585]

My playing with pcb wasn't so delightful as yours seems to be ivconic I just soldered and de-soldered wires where the plug is on the pcb (first your picture shows that area).

Anyway will try to check those things. It may take me some time as I'm a bit busy during week days. Thanks a lot ivconic.