Blue excalibur falsing hotspot

[ntx4509]

I bought an excalibur used 6 months ago. I noticed right away when in the water it would false. I have read about the settings to be lowered and all and it does help. I have found 26 rings since May so I assumed it was working great. I lube the battery connector allso. Recently ive been paying more attention to the falsing and noticed its not so bad untill the housing gets dunked and the falsing is somewhat worse.
After work today I looked at the cables and connectors closely looking for leaks and found none. So I turned it on and listened as I gently spread and wiggled cables. What I found was a spot on the housing that caused falsing. I can tap this spot, slide a finger back and forth and even just barely not even touch it and it will false.
Is this normal? Is this bad shielding? The pic shows area of hotspot. Does anyone else have the blue excal 1000 to test theirs?
Thanks
Greg

 

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[OBN]

Not the normal, I have a couple I will have to check them out. No Moisture> Have you checked the O-Rings on the knob shaft, they maybe Dry-rotted. Also Check and see if you can see a moisture pack in that area, maybe it is shorting the PCB (main board)..............as you can see from the picture there is not much in that area..I have a couple apart right now, will check this area out...get back to you.......congrads on the 26 rings..almost worth not messing with her..I have found some excaliburs are hotter then others...and it is the ones that false more then the others.....overly senstive.....

 

[Hangingfor8]

I had this problem as well and it turned out to be a leaky O-ring. I ended up killing the main board while diving with it. Don't get it underwater or you risk killing it. It's not a cheap fix if you fry it, but to send it off while in the offseason to have it checked out is a lot easier and cheaper than having it die in the middle of the summer. Good luck with it.
Will

 

[ntx4509]

thank you guys for responses. this unit is no longer under warranty. i will open it and replace o-rings.just found it odd just touching the housing would cause problems.i will inspect inside closely.
thanks
Greg

 

[OBN]

O-ring sizes, get them at McMasterCarr...Plummer Grease or Dow Corning 111 to lubricate the O rings..make sure you turn all the knobs to the far left before pulling the PCB, MainBoard..keep us informed on the outcome....

Smaller oring 2 per shaft.................... 1.5mm thick x 3mm ID, 6mm OD

top Oring 1 per shaft...........................1.5mm thick x 5mm ID, 8mm OD

the large end cap housing o ring..........3mm thick x 32mm ID, 38mm OD

 

[ntx4509]

Ok I opened my excal and saw right away there were 3 gel packages wegded between the circuit boards and one was at the location of the falsing hotspot. I removed all three reassembled and the problem still existed. I was unable to remove and inspect the oring at this location. The set screw is broken. But a close look at the shaft shows no sign of leaking.
I have been a electronic hobbyist for quite some time and this problem seemed to me more like electrical interference. I talked with a instrument and electronics tech at work and he agrees. I tried some different settings and the problem is apparent without even touching the housing. This hotspot area is picking up stray electrical signals from the waves while detecting as well as my finger movement over this spot.
As a experiment I applied a patch of aluminum duct tape over this area. The problem dissapeared.This shield as far as on the bench test eliminated the falsing. Which makes sense when you read about the excal II having shielding.
Aluminum Tape may not be the best for salt water but I am going to try it anyway. I remember reading about someone else using copper but the thread ended and there was no end result as far as how well it worked.
Hmmm we shall see
Regards
Greg

 

[OBN]

The self adhesive copper worked great, got it from digkey..about 13 dollars..they only problem I had was grounding the shielding to the PCB, which I did by grounding the discrimination knob shaft to the copper then it goes thur to the PCB. Used it one summer, copper was not affected by the saltwter..maybe 15 hunts on this machine...this and a carbon fiber shaft allow more senstivity to be run......
http://search.digikey.com/us/en/products/11.5X12-6-1126/3M9885-ND/2649430

 

[ntx4509]

was grounding the shield necessary? did you try with and without ground?

 

[OBN]

I don't think it is necessary because the one's on the Excalibur II's are not grounded, as I was putting it together I was looking for a way that was easy, without major changes. As a test, this way worked but I have to switch to a different metal to use, I used coiled solder. Ran it under the copper shield then up to the shaft, turned the shaft to one, far left..then put the knob on. When I pulled all apart for winter inspection the solder hard started to corrode.

 

[ntx4509]

Thanks oldbeechnut for all the help. I think shielding is going to help me a lot. By the way that's a nice looking new skin. Is that available for download somewhere?

 

[stevemc]

Aluminum duct tape will hold up in salt water, beer cans last for many years. Even the steel top aluminum beer cans hold up for a while - being a disimilar metal combo. You can get it by the small or large roll in the A/C duct dept of any big hardware store.

 

[ntx4509]

Just happened to have a roll. next up will be decals to label the controls and cover up the shiny finish.

 

[OBN]

By the way that's a nice looking new skin. Is that available for download somewhere?

The file is big, I have to figure out where I can post it to download, they are photoshop files...they were test runs..one is lite color the other dark.. both got in some beach time and did very well..I will be doing a few more this winter..closer to stock..I would like to do one similar to the original sword model..let me check around for a place I can upload them, these were printed on vinyl...........And applied over one EMI copper shield, and one EMI Aluminum shielding..both worked, and I seen no difference in the two shieldongs. Like I said on the excal, and yours it seems...Some are hotter then others..the adjustments for that are on the third level PCB Board of the excalibur.....Give me a week and I'll see if I can get them to were they are downloadable

 

[ntx4509]

Don't worry over it too much oldbeechnut I can whip something up using google sketchup.

 

[Treasure_Hunter]

Some really nice decal work there OBN, let me know if you decide to sell any of them, I need to replace decal on one of mine....

 

[dbsmokey]

OBN,

You're the master at Excal tweaks. Thanks for the information and the templates!

 

[OBN]

Thanks TH and DBs.................Treasure Hunter, these were printed on vinyl, alittle heavier material then the original blue decal..I'm not real happy with that and have located a vendor that can do them very close to the original material..it maybe early spring, but I hope to work up a couple more designs..some closer to stock. I know there are alot of older excal's needing that.........these were about 8 dollars each to have made, not to bad for a face lift ...Thanks for asking, I'll keep you informed........

 

[stevemc]

I have an old blue sword excal if you want to see how it is done. All decals are still in good shape.

 

[Treasure_Hunter]

Thanks TH and DBs.................Treasure Hunter, these were printed on vinyl, alittle heavier material then the original blue decal..I'm not real happy with that and have located a vendor that can do them very close to the original material..it maybe early spring, but I hope to work up a couple more designs..some closer to stock. I know there are alot of older excal's needing that.........these were about 8 dollars each to have made, not to bad for a face lift ...Thanks for asking, I'll keep you informed........

Winter, Spring, Summer want matter, I will always have an Excal so it would be nice to have a clean looking detector...

 

[OBN]

Thanks Steve for the pic it will come in handy, that has to be one of the very earliest models..with the aqua handle sword..were your headphones aqua also? Can you see thur to the main board and see a number..might be one of the first batch.