Can you explain a little more? I use a 1236 X2 frequently and find it to be stable, with a lot of adjustability.
I suspect you are encountering one of two things: iron in the soil, or electrical interference - and are unaware of it.
Just today I was in some iron infested spots, which were right under or around power lines. These conditions were driving my pals Whites Classic ID bonkers. This is normally a pretty stable machine, but it was nearly unusable in some spots we hunted. Not so the Fisher 1236X2. In fact, he tried my 1236X2 for awhile and exclaimed, "DO NOT sell this detector. It is great!"
Keep in mind that iron is the Number One issue with these Fishers. All other metals will act normally, but iron will cause the detector to appear erratic if you do not know it is there. So, you have to make some changes to your style so you can gain an "iron awareness."
1. Get the DISC up to around "4.5"
Any lower, and it will hit hard on nearly all iron.
2. Use the intrinsically fast target response to good advantage
Sweep at a goodly clip. Targets will come in clear and sharp
3. Use the intrinsically slow speed response to good advantage.
Once you have narrowed down on a target, remember one thing - targets of good metal will remain clear as you slow down over them and raise your coil. But iron will break up quickly and disappear as the coil raises away from them. This gives it away.
4. Keep your SENS down at preset or below unless you are in clear, trash-free soil.
As always, elevated SENS settings cause erratic operation.
5. Hunt with the SILENCER off, and listen to the pops and crackles caused by iron.
This is how you will know it is there... by getting to know it. The 1236X2 is a good iron discerning unit, if you let it be that. It is famous, in fact, for it's "snap crackle and pop" response over iron, so don't fight it
6. Switch to Pinpoint if you think you have an iron target.
This will "bloom" the target and swell its audio response widely, a sure sign it is iron. Good metal items and coins will, by comparison, give a tight, sharp response in pinpoint.
7. Switch to the SILENCER when there is just more iron than you can tolerate.
Each site is different, and each person has a different trash tolerance.
8. Understand what the frequency shift does.
As I mentioned, I hunted right under large power lines, with a substation directly across the street. I had to reduce my SENS to near preset and work the FREQ shift, until I found the "happy zone" where the detector stopped "chattering" from the electrical interference.
Practice all this at home, so you will know what is going on in the field. Remember, iron is the WORST trash target we face. Pull tabs and foil are easy to detect and discern, and we can discriminate them pretty reliably.
But, iron causes more problems than most people know, because it masks the other responses we desire and makes you think your detector is erratic.
The 1236X2 will let you accomplish the necessary "iron learning," if you let the detector teach you. Once you get the hang of it, you'll find the 1236X2 to be a great detector.
