Gpx 4500 problem

[Steefan]

Hello everyone
I have a problem with my gpx 4500. I used contact cleaner for connectors and shorted something. I open detector and saw what is fried. Its resistor 0,4 ohm i think(check picture). It’s power button circuit . I changed it with same but as soon i connect battery it is burnt again. Can you please help me with repairing?

 

[axtyr]

That is unfortunate. Either you have cross soldered another component or another component is also faulty. It looks like you now have 2 fried resistors.

If you are in Victoria then Mick the Mechanic in Dunolly should be able to fix it for you. He is currently unavailable until about June for the birth of another child. Send him a message and he will get back to you. www.detectronicsaustralia.com

You can send it off to Minelab but I don't know if they will repair it if you have attempted repairs yourself. Another choice might be the Miner's Den in Bendigo.

With any luck you will find the cause and be able to repair it yourself without having to send it away, hopefully. Good luck.

Regards Axtyr.

 

[davsgold]

are you sure it's not a faulty power cable, I would be checking it, a shorting out power cable can do this

 

[Steefan]

That is unfortunate. Either you have cross soldered another component or another component is also faulty. It looks like you now have 2 fried resistors.

If you are in Victoria then Mick the Mechanic in Dunolly should be able to fix it for you. He is currently unavailable until about June for the birth of another child. Send him a message and he will get back to you. www.detectronicsaustralia.com

You can send it off to Minelab but I don't know if they will repair it if you have attempted repairs yourself. Another choice might be the Miner's Den in Bendigo.

With any luck you will find the cause and be able to repair it yourself without having to send it away, hopefully. Good luck.

Regards Axtyr.

The picture attached is first blow. I think contact cleaner shorted somewhere because i didnt wait and connected power right after spraying. Unfortunately i dont know what blown element is- resistor or inductance. I have no schematics so i hope someone to help me. My last option is to send it in Australia because im in Europe, so first i will try repair myself.

 

[Steefan]

are you sure it's not a faulty power cable, I would be checking it, a shorting out power cable can do this

I will check but was working fine before contact cleaner.

 

[axtyr]

Bummer.

 

[user 4485]

The picture attached is first blow. I think contact cleaner shorted somewhere because i didnt wait and connected power right after spraying. Unfortunately i dont know what blown element is- resistor or inductance. I have no schematics so i hope someone to help me. My last option is to send it in Australia because im in Europe, so first i will try repair myself.

There are a number of Minelab Authorised Service centres in Europe (if you do no good):
https://www.minelab.com/anzea/support/service-support

 

[axtyr]

Steefan, one other option you have is to send an email to Mick and he might be able to tell you what those components are and their value.

Regards Axtyr.

 

[Steefan]

Steefan, one other option you have is to send an email to Mick and he might be able to tell you what those components are and their value.

Regards Axtyr.

I will try contact him!
Thanks

 

[Noodlez]

Unlikely that contact cleaner was the culprit as it's usually non conductive.

 

[Moneybox]

In all the years I've used the GPX4500 I've only had two faults. The most likely is the curly cable to the battery. It gets a good workout and usually breaks near the plug and providing no other damage is done it's an easy fix. I'd start there. The only other fault I had was the big nut securing the input plug came loose allowing the socket to move in the housing. It has to be tightened from inside.

 

[EVIE/BEE]

I won't be calling you to fix my plumbing.

 

[Steefan]

Unlikely that contact cleaner was the culprit as it's usually non conductive.

I know but the fact is after contact cleaner something shorted. The burned element is inductance, maybe some kind of fuse.

In all the years I've used the GPX4500 I've only had two faults. The most likely is the curly cable to the battery. It gets a good workout and usually breaks near the plug and providing no other damage is done it's an easy fix. I'd start there. The only other fault I had was the big nut securing the input plug came loose allowing the socket to move in the housing. It has to be tightened from inside.

I had the nut issue too.
Machine is working again. What i did is to solder:
INDUCTOR-SMD,2.2UH,20%,2012,0.16OHM,950M
After that i feed it direct 7,6v to power strip with dc power supply. Luckily machine boot up normal. Then tested audio from the machine itself and it was good. So my thoughts are something in the battery/cable is causing troubles. Cable was tested for shorts and its ok. Battery was opened and I did some measurements for shorted caps but nothing wrong. After that i connected everything as it was: battery power cable and detector. This time nothing burned. Machine boots normal.
I have tested it for 3-4 hours and it’s ok. But older problem, for which i used contact cleaner is here again: chattering and something like high EMI.
Thanks to everyone for the help!

 

[axtyr]

Well done Steefan, hope it keeps working.

I had an issue with my battery and had to replace some SMDs for the audio. I discussed the problem with Mick and he mentioned that the curly power cable was most likely the cause. It can break about 50mm from the end but only cause intermittent shorting. I did replace the plug but haven't been game to use it again. I bought a new one.

Glad you got it working and good luck with it continuing to work.

Regards Axtyr.

 

[Steefan]

Well done Steefan, hope it keeps working.

I had an issue with my battery and had to replace some SMDs for the audio. I discussed the problem with Mick and he mentioned that the curly power cable was most likely the cause. It can break about 50mm from the end but only cause intermittent shorting. I did replace the plug but haven't been game to use it again. I bought a new one.

Glad you got it working and good luck with it continuing to work.

Regards Axtyr.

Thank you Axtyr!
Can you tell me which SMDs you changed? I had sometimes problem with audio- from time to time sound level go down by itself. Fix is restarting machine. It’s happening on earphones. I don’t work with external speaker. Maybe i need to replace power cable too.

 

[axtyr]

Steefan, my problem was I lost the battery mounted audio boost. I could still hear the sound but it was veery faint. The problem is with the components on the battery PCB. Your problem sounds quite different in that you are getting static noises through the headphones/speakers. That really sounds like a cable problem. I really would suggest replacing the curly cable first. It would be very beneficial if you knew someone that also had a detector that used the curly cable so you could swap it and see if your problem goes away.

I ordered the Steelphase battery audio repair kit and it has been fine since. The kit comes with the components, the instructions for opening the battery case and replacing the components and a picture of where the components are located on the PDB.
.
The components are 2 Schottky Diodes, 2 analogue switches and an Op Amp.

I am reluctant to distribute the component identities due to the fact that Steelphase supplies this kit as a part of his income and by doing so might be detrimental to him.

However, you might try emailing or PMing him (when you have 10 posts up), explaining your situation and he might be kind enough to give you the information you need.
First up I would try another cable. If it doesn't work then you have a spare cable.

Regards Axtyr.

 

[gef12]

I know but the fact is after contact cleaner something shorted. The burned element is inductance, maybe some kind of fuse.

I had the nut issue too.
Machine is working again. What i did is to solder:
INDUCTOR-SMD,2.2UH,20%,2012,0.16OHM,950M
After that i feed it direct 7,6v to power strip with dc power supply. Luckily machine boot up normal. Then tested audio from the machine itself and it was good. So my thoughts are something in the battery/cable is causing troubles. Cable was tested for shorts and its ok. Battery was opened and I did some measurements for shorted caps but nothing wrong. After that i connected everything as it was: battery power cable and detector. This time nothing burned. Machine boots normal.
I have tested it for 3-4 hours and it’s ok. But older problem, for which i used contact cleaner is here again: chattering and something like high EMI.
Thanks to everyone for the help!

check cable for continuity .. whilst moving the cable near the end connectors ... often there are breakages there ..
good luck
gef