Last week i a got a call from Ralph at Sun Ray Electronics, who brought other good information to my attention about the F75 and chattering.

I have to say that i never used notch on the F75 before (just disc) but after playing with notch and disc i was able to reproduce what Ralph talked about.

Here is some examples what can happen if you use notch and disc:

1. If you set DISC to 0 and use Notch to cancel out target group 1 to 7 you still have accepted 0 and that causes the detector to be unstable.

2. If you have DISC set anywhere from 1 to 7 and up and you go to notch and select any number from 1 to 7 you have NOT notched out the numbers, you have notched them back in (accepted them), because Notch does the opposite from the current disc setting. That will cause the detector to be unstable again, because accepted numbers from 0 to 5 run a higher preamp gain.

3. If you think you have messed up your Disc/Notch settings do a factory reset by turning the detector off and then push the trigger forward and press menu button while turning the detector back on.

I hope that will help some guys not to have to send the detector in for repair for something that is not broken.

Thanks Ralph for the input,

Andy,NM

F75 FAQ's :

Q 1. : Why is only one rubber washer for the lower stem in the box ? Is one missing ?

A: The F75 comes with only one rubber washer, because that's all you need. If you feel you need a second one contact the factory at: 915-225-0333

I bet they will be happy to send you a second one.

Q 2. What are the best settings to start with ?

A: When you start the F75 up the first time it starts in DE processing, Disc at 10 and sensitivity at 60. I found it to be a perfect setup to start with. Before you change anything make sure you get a feel for the detector with the above settings.

Q 3. After I ground balanced the detector with fastgrab it can't find a coin on the surface. Why is that ?

A: Make sure you don't see the words " can't GB" on the display while pumping the coil up and down over the ground.If that happens the detectors performance is close to zero after you release the trigger.

Q 4. The detector seems to pick up ground noice after ground balancing with fastgrab. What is wrong ?

A: When using fast-grab the detectors seems to be right on with the ground balance. It is so good that after ground balancing every tiny change in the ground matrix is seen as a target. I use fast-grab first and then change to manual ground balance and GB the detector plus 3 numbers. So if fastgrab was 70 I set it to 73 (positive offset). That way the detector doesn't see very small changes in the ground matrix as a target anymore. 3 numbers plus is about what a 1/8 turn on a 4 turn tesoro ground balance would be.

Q 5. I can't find the warranty card in the box of the F75. How can i make sure i get warranty service ?

A: Just keep you receipt from the dealer who sold it to you. You have 5 years warranty from the day you bought it. I taped the receipt in the F75 box to make sure it won't get lost.

Q 6. What are the hottest setting for the F75 ?

A: What sensitivity and modes can be used are controlled by the ground conditions and location (interference free or not).
I always start in the DE mode, Disc 10, sensitivity 50.
If you can push sensitivity high in that mode, it is an indication that you may be able to use the JE mode. But before you switch over to the JE mode make sure to lower the sensitivity. Because you can run sensitivity at 90 in DE mode doesn't mean you can run that same sensitivity in JE mode. On the other hand sensitivity at 60 in JE mode can be deeper than sens at 90 in DE mode. Some locations may not allow to use JE mode but DE mode could work just fine.
The target is to run as much sensitivity as possible while remain a very stable detector. That balance changes with ground condition and location.

Q 7. I can't get the F75 to work at the beach. Do you have some beach settings ?

A: First you need to know that most beaches ground balance under 40. That means you can NOT use fastgrab. You have to use manual GB to balance to ground under 40.

To avoid reflections from the salt use the DE mode and lower the sensitivity (Not JE mode because the gain is to high for salty ground).

Q 8. Even in DE mode the F75 is very unstable and noisy. Why is that ?

A: If you set the Disc lower than 5 or higher than 19 the detector runs at a higher gain in DE processing. That higher gain means more depth in interference free and mild ground areas but if interference or bad ground is present the detector becomes noisy and unstable.

For best stability run disc between 5 and 19 in DE mode. Reduce sensitivity too if needed.
The JE processing mode has a much higher preamp gain than the DE mode and is very sensitive to interference sources like cellphones, lightbulbs, power lines. If the detector goes crazy in that mode go back to DE mode and set Disc between 5 and 19.