need minelab gp 3500 schematics ( for audio schematic)

[ademadem]

The audio output of my 3500 does not work.

perhaps, power (audio) cable may have inserted it incorrectly,

Waiting for help from people experienced in this field.

White coating on the PCB, the PCB can remove without causing any harm.

Best Regards

Adem Adem

[kt315]

White coating on the PCB

try to clear PCB by spirit. can you give pics inside or you mean only theoretical labour, labour of thought?

[kt315]

anything progressing?

[ademadem]

I tried cleaning with alcohol and lacquer thinner,

I checked the diode (2x A7W), no problem

[kt315]

try to use nail enamel remover, every woman uses it.

[Mechanic]

Hi Adem,

There are many reaonswhy the audio may no work on a 3500. If the coil is not connected, the audio will appear not to work. Have you checked thepower/audio cable? Different headphones? Are yu trying t drive a speakerdirectly from the detector audio output? It will not drive a speaker without a booster.

In my opinion, you are better off sending this to minelab and have them repair it than to attempt repairing it yourself. It will be money well spent. If you try and repair it yourself, you will

Nail polish remover will not touch the paint used on he ML boards, it will just dissolve the plastic coating of the wires and melt the capacitor casings!

Cheers Mick

[kt315]

Nail polish remover will not touch the paint used on he ML boards, it will just dissolve the plastic coating of the wires and melt the capacitor casings!

aceton+water is not so aggresive inveronment you so fear. please DO NOT SPREAD OUT A PANIC!

[Mechanic]

Nail polish remover will not touch the paint used on he ML boards, it will just dissolve the plastic coating of the wires and melt the capacitor casings!

aceton+water is not so aggresive inveronment you so fear. please DO NOT SPREAD OUT A PANIC!

KT, with all due respect, I have soaked a ML board in acetone for over 12 hours(with the capacitors removed) and it did nothing to the paint whatsoever. The only thing it did do was stuff the insulation on the wires that go to the board. I also tried high quality paint thinner and it had no effect either.

When he tries to fix it on your encouragement and fails, who is he going to send it to to have it repaired? ML won't touch it, will you fix it for him? I am giving sound advice, which I hope Adem listens to, it is not some cheap $2 toy detector in question. The 3500 will still fetch about $2500 here in Australia. Whats $150-$250 to have it repaired?????

Cheers Mick

[Nupi]

Hello, I do not think that minelab used a solvent paint thats would be risky for the parts.
You should think more of waterbased paint used. That is dificult to solve, remove.

[Nupi]

What happens to the paint as warming up with a soldering iron?
Will it be soft?

[Mechanic]

Hi Nupi,

Hot air from a rework station softens the paint which can then be removed with a small flat screwdriver(without bent edges). However, the part numbers are all scratched off the ic's, so even once the paint removed, you are still flying blind. It takes a lot of experience to be able to reverse engineer any of the ML pi's and a hell of a lot of time. For a one off repair it is just not worth it, whats your time worth??? $1/hour???

Adem, You say the audio is not working, can you confirm that the coil is pulsing? Do you have a scope? If you don't have a scope, I STRONGLY suggest you re-assemble it and send it off for repair, even if you do have a scope, still send it in for repair, or I will give you $200 once you have finished with it....

There are no schematics for this machine publicly available. It is very different to the sd2000.

Cheers Mick

[Nupi]

Hi Nupi,

Hot air from a rework station softens the paint which can then be removed with a small flat screwdriver(without bent edges)...........

Ok it's what I thought waterbased paint (thermoplastic)
Thanks for your info.

[Mechanic]

Ok it's what I thought waterbased paint (thermoplastic)
Thanks for your info.

Excellent Nupi, thank you for your info too! I had often wondered what sort of paint it was....

Cheers Mick

[sinclairuser]

on this occasion mechanic is right dont mess send it in, this detector is too expensive to mess with, soap powder blasting removes the paint, but the markings are missing anyway, its not worth messing up.

[Finderskeepers]

Had my gp3500 sent of to Minelab last year for repair - a resistor in the transmit section of the circuit was gone. Great service department to deal with and was fixed and service within two weeks. Cost of works was au$90 (excluding postage). These detectors are precision equipment and best left for Minelab to repair. I highly recommend that you get some sort of postage insurance.