MX 5 THRESHOLD VOLUME INCREASE

[Bill ( So. Ca.)]

I recently purchased an MX 5 and when operating it (with headphones) I've noticed that after about 1 hour of detecting the threshold volume will start to increase. It went from an initial setting of 13, and as the sound amplitude increased I had to adjust it down to 1. Has anyone else had this issue? Thanks, Bill

 

[RLOH]

Bill, I have had two MX5's with the same issue. I never found it to hinder the performance of this fine detector. I just re-adjusted the threshold and kept on trucking. I called Whites several times and never got an answer to satisfy me. Send it in and we will look at it is what I was told.

 

[Hombre]

There have been recent posts about this issue and also another one involving a change in tones...and these MX5 were new in the box (new old stock) sold by a dealer.
I'm computer illiterate and don't have a link to prove it. The change in tones is a well known issue and it involves sending back to factory for a minor fix by removing 1 resistor.

 

[taterbill]

These are two different issues! I've had the same issue of threshold getting louder as mx5 gets warmer...had it this summer. On a warm day... about 85 deg...the outside of detector will get much warmer when exposed to the sun. As control box gets warmer, you have to keep turning threshold down to keep sound at a low level, which is where most people like to hunt. On a real hot day.....90 deg, & control unit in the sun, threshold sound gets so loud that you can't turn It down any further...no adjustment left. I remove coil, rod, & batteries, and place control box in a refrigerator for 5 minutes....or cool place to allow the box to cool down. Put it back together and it works great! I've repeated this process many times.
I talked with Whites, & sent it in three times...they couldn't

duplicate the problem. They replaced circuit board....didn't fix it.
To their credit, they sent me a new-in-box replacement. It does
the same thing, though I think it's a little less sensitive than my original. I really like the mx5, but I personally think its a design problem. This same problem has been described in another forum, but a fix was never described. If anyone has the problem of mx5 threshold getting too loud on a hot day....try cooling off the control box. Let me know if it works. I was thinking I was the only one having this problem.
Taterbill

 

[taterbill]

More info.... after cooling off control box, then re-assymbling, unit works great. However, after taking unit back out into hot sun, & warms up, problem returns. There's something in the control box that doesn't like the heat....maybe a weak component. This problem is only noticeable when using ear phones.
Taterbill

 

[Bill ( So. Ca.)]

Hi Tater, I've come to the same conclusion you have that the problem is thermal. When the detector gets hot in the sun it starts a thermal runaway condition. Whites engineers should be able to correct this issue with a component change or circuit redesign. I sent whites a message regarding this problem, lets see what their response is. Thanks for your input. Bill

 

[Hunt4Fun]

Hi Bill, wishing you good luck finding the solution to the threshold problem.

 

[amberjack]

its an mx5 what else is there to say.

AJ

 

[taterbill]

"Bill (So Cal)"...did u ever find out , from Whites, anymore info on the mx5 threshold thermo problem?
taterbill. You can email answer if u wish..