Issue with the Minelab Excalibur ii constant noise

[Bjorni]

Hi,

Just purchased a used Minelab Excalibur II from 2015 that is in excellent condition, hardly used. When I connect the battery I hear this weird noise from the headphones and it does not matter if the threshold is turned on/off. I read some forum post on the forum about checking the battery connector and adding som silicone grease on this to see if that helps will try that later today, but im not sure if this behavior is from a shorted battery connetor. I made a short video to show the issue and all suggestions are appirchated.




Bj?rn

 

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[Treasure_Hunter]

Check the voltage on your battery, Excal needs min of 12 volts to run properly, you may be getting low battery alarm if battery is below 12 volts.

 

[Bjorni]

Check the voltage on your battery, Excal needs min of 12 volts to run properly, you may be getting low battery alarm if battery is below 12 volts.

Yes, i thought it was the battery. When i measured it yesterday it was 12.2V but charged the battery overnight and now the battery is at 14.4V and i expect this to be normal battery voltage for the NiMh battery pack. Any other suggestions?

 

[Treasure_Hunter]

Yes, i thought it was the battery. When i measured it yesterday it was 12.2V but charged the battery overnight and now the battery is at 14.4V and i expect this to be normal battery voltage for the NiMh battery pack. Any other suggestions?

Yes that is good voltage so it is something else.

First, on the excal volume should always be max, volume is what gives you the different tones.

Does it give you the same static noise if you are outside away from any electrical lines over head or under ground? It could be a bad headphones or it could be a bad capacitor. If it is still doing it out side away from any overhead or under ground lines then you need to send it into Minelab repair.

 

[Bjorni]

I have some unfortunate news regarding the noise issue.

I bought the other day a used Minelab Excalibur II and the guy I bought it from only used a handful of times on the beach. He sent me a video of the detector in full working order without issues before sending it to me. See video:



When i had my first dive trip with the detector the other day i noticed issues with the detection and the sounds coming from the headphones so at 10m and only 10min in the dive I aborted it. When I came back up I thought it was the battery so I put it on charge overnight and when I tried the detector today the was a constant noise from the headphones even if the detector was off. See video:



So took a closer look and saw that there was a liquid inside the main control unit. So I thought it was best to get this liquid out as soon as possible so I open the tube and drained the fluid.See video:



After further investigation of the end cap with the cables going to the battery and coil I saw there was a crack in the plastic were one of the set screws are and I suspect this is causing the leak into the control unit. See video:



I have soldered off the wires on both ends of the PCB and cleaned the PCB with a ultra sonic cleaner and let it dry and tried to reconnect the cables without luck. There is no sound coming from the headphones.

Voltage/Ohm reading between pins on PCB Rev 3.3:

Power side:
-B & +B : 13.66V

Coil side:
RXA & TXA: 1.396V
RXB & TXB: 1.623V

Headphone side:
2pin connector Red & Black: 13.06V
2pin connector Red & Red screen headphone cable: 13.64V

Potmeters:
Discrimination: 0.3-29.16Ohm
Sensitivity: 0.3-30.07Ohm between 3 pins & pot.switch ok
Volume: 0.3-10.16kOhm between 3 pins
Threshold: 0.4-30.30kOhm & pot.switch ok
Pinpoint/disc: 3pins all readings show 0Ohm & pot switch ok

From those measurements I think the pinpoint/disc potmeter is destroyed as there is no change in the Ohm value when turning the potmeter.

So my question is what options are there with trying to get this unit back in working order as a land only unit. Is it possible to order a new PCB/parts(potmeter). Is there a way to easily jump the pot meter to see if that makes the board come to life? Any thoughts are much appreciated, sorry for the long post

 

[Treasure_Hunter]

Beat advice I can give is send it in to Minelab repair, Minelab will not sell parts so you would have to find it on your own and soldering on MB is tricky as the etchings are thinner than human hair and you can destroy the etchings if not very careful..

 

[Bjorni]

I think I can fix this, just need some guidance on which parts to replace. I found the potmeters on digikey, but I don’t understand why the values I’m measuring differ from the other forum posts from OBN saying the potmeters are 10KOhm and 100KOhm. Does anyone know the model code for the potmeters on Excalibur II. And would it make sens that the fault would be no sound out from the pcb?

Link to digikey:

39SB-1RB-103 POT 10K OHM 1/4W PLASTIC LINEAR
https://www.digikey.com/en/products/detail/bourns-inc/39SB-1RB-103/954399

39SB-1RB-104 POT 100K OHM 1/4W PLASTIC LINEAR
https://www.digikey.com/en/products/detail/bourns-inc/39SB-1RB-104/2564488

Data sheet Potmeters:
https://www.bourns.com/docs/Product-Datasheets/39.pdf

I know that you need to mod the rod on these potmeters to have them work but that should be okay.

I will move the wire further away from the coil

 

[ARC]

Well one of your problems is your wire... it is wrapped too close to coil / laying on coil.

Remember... IT contains metals.

 

[Treasure_Hunter]

Here are a couple repair centers in Europe

[FONT=&quot]International Detector Center GmbH[/FONT]
[FONT=&quot]Bunde-West, Germany
T: +49 (0)49537082810
E: [email protected]
W: www.idc-detektor.de [/FONT]
[FONT=&quot]MSR
[/FONT]
[FONT=&quot]Surrey, United Kingdom[/FONT]
[FONT=&quot]T:[/FONT][FONT=&quot] +44 (0) 208 241 4789[/FONT]
[FONT=&quot]E: [/FONT][email protected]
W:[FONT=&quot] [/FONT]metaldetectorrepair.com[FONT=&quot]



[/FONT]

 

[OBN]

Sorry I did not see this earlier! Anytime you hear static in your audio it is water intrusion ....some where. Head Phones, Control pod, power cable, or fitting. Water in the coil or coil cable will make the machine false just setting. Water in the control pod will also cause the machine to act stupid, falsing.
Here is a lead on the Pot..Tsetsa Tsetsellin share this... https://minelabfrance.com/?fbclid=IwAR3I1GoOoha6PLb5QEkkQzgvUw9DU-bdG_x-ejvZP4DWmFJD4K-hjv-s4zs