Loud steady hum, no adjustable threshold on excal II

[softsand]

Last year I had a problem with excal II. When I first got to location, turned it on, it was fine. If I shut it off for a minute or two, all I could get was a very loud, unadjustable threshold noise, could not recognize a target. I sent it to Kelly's. They couldn't find anything except put new battery in, and recommended trickle charger which I've been using.
This year less than 20 uses, loud steady noise is immediate, doesn't even start out working right. Battery tests at 14.5 volts.
Any ideas I hate to send it in again, until I have an idea whats going on. Thanks

 

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[ripp1]

I’ve recently developed the same symptoms with my 1st generation Excal. It will reset after charging but now only last 20 minutes before the tone comes back. Unit is 11 years old. Might be done for.

 

[bklein]

1. Test the battery voltage while it is in failing state. Could try replacing with a dc power supply. Vary the voltage to see if it stays working within 10.5-14V. Load is around 120mA.
2. Try shorting the threshold pot wiper to ground with a jumper while it is in failing mode. If that works but turning the knob doesnt you probably have a bad pot. (Yes, have to open it up) Can check pots with a meter.
3. Look for corrosion on any pcb traces or wire solder connections.
4. Try replacing the coil with another. Look for cracks in housing or coil cable.
5. Sell it to me really cheap. (Or trade ya a working surf pi....)

 

[Tommybuckets]

Are you in the water? Sounds like a battery short (low battery warning) as if water is getting into the battery connection.

 

[OBN]

I’ve recently developed the same symptoms with my 1st generation Excal. It will reset after charging but now only last 20 minutes before the tone comes back. Unit is 11 years old. Might be done for.

how old is the battery...I hope not 11 years old.

 

[Treasure_Hunter]

OBN is right, you could have a bad cell and still have 14.5 volts, measure the voltage with battery connected and turned on. Don't connect the locking nut, hook small strand of wire to each terminal of battery cable and plug it in to battery being sure not to short them together, hook up your ohm meter and measure voltage when you turn excal on, if voltage drops low you have a bad cell in the battery.

 

[AngerManagement]

Watching this thread... Have seen a few similar symptoms but different causes every time...

A: Battery
B: Bad wiring/connector to the Battery
C: Coil ?

 

[pat-tekker-cat]

I have the same thing happening on my older Excal, I think It's the battery.....
because, I take my other newer battery, hook it up and it doesn't happen.
Charge the old battery, it doesn't happen. I think on the old battery, it's just wearing out, doesn't hold the charge like it used to. Maybe good for short hunts, but for them all day long hunts..... I use the new battery.

Will be watching thread also.....

 

[lisfisher]

This is a longshot, but I had the same issue just last weekend. My battery is a brand new RNB lipo so I ruled that out. The problem was the discriminate/ threshold knob was stuck in between the two settings. Turned all the way to discriminate and the noise went away. Just grasping at straws here.