4500 SUDDENLY UNABLE TO TUNE

Yesterday I was detecting when the detector suddenly went out of tune. I tried to auto tune, changed the settings, turned it off and on. This continued for about 15 min then it suddenly came good. I had no other detectors in this area any thoughts.

A buried Telstra cable will do this nearly every time. But other considerations may be worth a look.
Most importantly: How old is your GPX 4500?

Cheers,

M.

No telstra 3 weeks old .

How far were you from power lines etc? Depending on time of day if there is a household line nearby interference can come in strong for a short period of time then fade off again, this is caused by people along the line turning on things like heaters/air conditioners, computers etc.

A buried Telstra cable will usually be constant once you get within close proximity as they tend to channel the Sferics, whereas a hammering coming in then suddenly going suggests a mains type interference as demand is increased on the line, best bet is to leave your menu select on Manual Tune and try adjusting a couple of points up or down at a time to see if you can get away from the worst of it rather than doing a complete auto tune.

If you have to Auto Tune then crank up the Gain and Motion filters to flat out first a these controls are pre auto tune, meaning the auto tune will take their information into account during the tuning process.

Hope this helps,

JP

A quick question for JP, when you say crank up the motion filter is that "very slow" or "fast" ? Which way is up ?
Cheers Mark.

Gday Bruno


This sounds exactly what happens to my detector, but it only ever happens in the Karratha area of WA, it has never happened anywhere else, I have put it down to some sort of communications or transmission lines as there is nothing else to see that might cause it.

It will happen all of a sudden and without warning and as you say will last several minutes, no alteration of settings will make it work any better, I just switch it off and wait for a few minutes, or walk away from that spot until it changes.

At first I thought that it was just my machine but there are two other people who are also using the 4500 and it happens to them as well so it is definately some sort of external interference, I have not used any other model of detector in that area so I cant say whether it effects them the same as the 4500.


cheers

stayyerAU

This has happened to my 2200v2 as well and iv'e put it down to aircraft.
I noticed a plane once when it happened and another time when i took off my headphones i could hear one in the distance.
It lasts about five min or so and you might as well take a seat and take in the scenery because no amount of tweaking will settle it down.

mark, Jp is saying to turn the motion to fast and gain to 15, then do a tune, then put motion and gain settings back to the levels you want to detect in.
Tributer

Gday Fisherman


One area that I used to detect a bit was between Paynes Find and Yalgoo and on occasion my 3500 would play up, a bit like lightning strikes in the distance, the only factor I could put it down to was the planes going overhead as like you I would hear them, seems that area is under the flight path to the North of WA.

I just put it down to something to do with the pulses from their radar or the like, some other areas I detected in were also along the same route but the further North you go the less the interference, I put that down to the planes being at a higher altitude, as you would not hear them but you would sometimes see the vapour trails.

cheers

stayyerAU

stayyerAU wrote:
One area that I used to detect a bit was between Paynes Find and Yalgoo and on occasion my 3500 would play up, a bit like lightning strikes in the distance, the only factor I could put it down to was the planes going overhead as like you I would hear them, seems that area is under the flight path to the North of WA.

G'day Stayyer, Here in Vic most of the goldfields are under a flight path and the planes are generally not extremely high yet due to the proximity of the two mayjor airports. Your right with the interferrence from planes, It is rather like a lightening strike they give you a real ping!

G day all
The type of interference i'm talking about isn't like the ping of lightning it's a sudden wobble in the threshold that quickly builds to something like an alarm going off.
It usually lasts a few minutes then fades off again leaving you with a steady threshold and a blank look on your face
It's only happened to me maybe five or six times and i have given up trying to do anything about it, i just turn the detector off and sit it out.

Fisherman wrote:it's a sudden wobble in the threshold that quickly builds to something like an alarm going off.

I've encountered this a few times as well. I have spoken to others who have had this happen.

It's a high then low tone. Very annoying!! Has anyone an explanation for this?

I had it only hapen to me once had a feeling it was somthing electronical that got stuck .

My wife and I have been detecting in an area of Dunolly in Victoria for several months now. I with a 4500 and she with a 4000. We both suffer this "warble" in varying degrees. Yes, we are under a major flight path.
I sent the 4000 back to Minelab to be checked with a detailed account of the warble. It came back with a report saying it was in perfect health.
The 4000 seems to suffer more than the 4500 at a ratio of about five to one.
We just switch off and wait several minutes. There's nothing else you can do.

Robert

Robert do you believe something is sticking within the circuit ? That's the feeling i get. There seems to be a lot of people having similar problems with their machines, I believe it can't be a coincidence that numerous people are having the same problem when external factors in certain areas don't seem to play a part in the reaction that the detector is having with the ground mineralisation.

This may have been said before, but when this happened did you try adjusting the manual tune ?.
If it the same thing several of us have experienced (starts of with slow a high/low and the high/low seems to increase in speed up to were it almost no high/low and then starts to slow down) if this sounds familiar a simple adjustment of the manual tune function will remove it.
As for the source many have there own reasoning to explain the interference some say planes overhead etc. But it seems to happen when no planes are visible go figure?????.
There is probably nothing wrong,but if in doubt send it back for a health check up.
Regards
John

Hi John i have often tuned out interferance with my old 4000 the 4500 in the same area with extra setings i believe is a powerful tool don't have the experience of most of you guys but i have been out 4 days always picked up yellow , compaired to 4000 feels like taking off gumboots and puting on runners i feel it might just be an inherant bug i will be back in the same area this weekend and see what happens.

Hi guys, if it could be determined that there was sizable aircraft around when this happens it could possibly be the Radar Altimeter. Larger Planes and military aircraft and helicopters use these and could be the source. It would explain the short duration of the interference as the area covered by the transmission is relatively small, and would disappear as the aircraft passes overhead.

SD

BRUNO C wrote:Robert do you believe something is sticking within the circuit ? That's the feeling i get. There seems to be a lot of people having similar problems with their machines, I believe it can't be a coincidence that numerous people are having the same problem when external factors in certain areas don't seem to play a part in the reaction that the detector is having with the ground mineralisation.

Hi Bruno,

Sorry for the tardy reply.
No, I don't think it's a circuitry problem but, then again, I'm no electronics whiz.
My 4500 does it far less than my wife's 4000.
As it's nearly out of warranty, I'm sending the 4000 to ML for a brain scan and physical.
I'll raise the issue again with them and ask-if it is an aircraft related problem or some such problem-why can't some sort of suppression be built in to the detectors.
Manually tuning can work but we find the easiest way is just to turn the detector off a wait a couple of minutes.

have a great day

Robert