has anyone ever owned this White's metal detector before? AF350

[keith777]

Hi all.

has anyone owned a White's AF350 metal detector before. or heard of it before. it needed the battery connector on the PCB board repaired first before i could test it, but that is done now. on doing some tests it powered on and the needle on the meter moves to the end. moving a metal object in front of the coil the needle moved up and down, but there was no sound from the speaker. i plugged in a set of headphones and this time i was getting a quiet threshold. so i moved a metal object in front of the coil again and this time the machine was giving a brake in the threshold every time the object past the coil.
any thoughts on this detector. is it working properly. can it be modified?

thanks in advance.

[keith777]

Some More Photos.

[Carl-NC]

The White's Inverness facility made a lot of their own custom products that were not part of the official White's catalog, usually for specific regional sales or maybe even for a specific customer. They would get all the parts from the Sweet Home factory and do the assembly in Inverness. This unit appears to be based on a "Classic" board. Otherwise, I've never heard of it.

[keith777]

here is my old whites classic board that i moded next to the AF350
what do you think the three pots are used for. i haven't tried having a fiddle with them yet. maybe Threshold etc. a Schematics for it would be very handy.

[kt315]

i grasp the meter used model was done for deaf men. it is specific detector vs classic.

[keith777]

i had a better play about with the machine late last. why i was just getting a quiet threshold sound when the tune knob had to be turned right the way up to hear any thing. was the headphones that i first tried on it. the jack plug was not compatible with it. once i tried a different pair of headphones the threshold works fine. the machine still won't give any sound when not using head phones. i am not sure what is going on there at the moment. the machine is some kind of PI by the looks of it. turn the tune pot till the needle on the meter gets to number 10. this give you a nice low/quiet threshold sound and that's it. you are ready to go. i tell you what. it has some really good depth on it on large and way impressive depths on very, very tiny objects.
i did try having a bit of a play with the 3 pots on the PCB board, but they didn't seem to make any difference to the operation of the machine that i could tell. i was picking up this tiny flat headed screw in the photo at over 3 inches in depth. which i assume would be good for a machine of it's age?
the screw actually looks bigger in the photo for some reason.

[Carl-NC]

No, the detector is a VLF based on a Classic or Classic/ID board.
The speaker may be blown, or the headphone jack not making contact. Not much else it could be if the headphones work.
The trim pots are:

• VR1 sets the GB point
• VR3 sets the quadrature phase
• VR5 adjusts the meter (full scale?)

[keith777]

No, the detector is a VLF based on a Classic or Classic/ID board.
The speaker may be blown, or the headphone jack not making contact. Not much else it could be if the headphones work.
The trim pots are:

• VR1 sets the GB point
• VR3 sets the quadrature phase
• VR5 adjusts the meter (full scale?)

what does. sets the quadrature phase mean.

thanks.

[Carl-NC]

It's the clock for the X-channel demod. Usually this is just set 90° from the GB point but for some reason the Classic design had it adjustable. It may have been used to calibrate target IDs.

[keith777]

i have found some info on the internet. next to non out there. it looks like there is also two other models of it out there but the 3 level sensitivity toggle switch is a potentiometer instead.

Whites AF-350 Metal Detector

3 Levels of sensitivity High, Medium and Low.
Finger trigger Battery check.
All Metal.
Whites 950 waterproof search head.
Built in speaker.
6.35cm (1/4") stereo jack.
8 x AA 1.5v batteries.
Simple but powerful.
An industrial metal detector.
High powered all metal machine with 3 levels of senitivity.
For confirming the locations of plumbing and steel plates laid. Detectable depth depends on size,type and orientation of metal and type of soil.

Whites AF-350 Metal Detector
Technical specifications
1 - Operating frequency: 6,592 kHz
2- Panelmeter: Analogue
3 - Detection depth: Depths may vary depending on ground conditions and the size of the target.
4 - Ground balance: Automatic
5 - Threshold signal: It can be adjusted by the user.
6 - Discrimination: Detects all metals, has no discrimination feature.
7 - Weight (Net): 2.04 kg
8 - Height: Adjustable between 115 cm and 135 cm.
9 - Standard head: Bulumax 950 (24.5 cm diameter)
10 - Operating ambient temperature: : -10 C to 60 C o
11 - Operating voltage: 12 Volts
12- Rated current: 50 mA
13 - Power source: 8 x 1.5 Volt AA batteries.

White's AF 350 is a metal search detector that finds buried or under asphalt valves, meter boxes, culvert covers, and manhole and manhole cover locators.


For example aluminums, brass and yellows, coppers, irons, nickels, steels, tins, and other types of metals. It offers effective search at maximum depth with its extreme sensitivity setting.

Features :
» It will automatically cancel the ground frequency interferences that may occur due to ground mineral.
» The electronic stability system of the AF 350, on the one hand, shows the detection intensity on the screen, on the other hand, it provides the user with an easy and fast setting for searching.
» The 25 cm head is designed to be absolutely waterproof. It is very easy to use and reliable.

» It is the most useful and economical detector that can easily locate underground manhole covers, valves, rebars and other metal objects. » Excellent sensitivity (3 steps) » Density measurement » Detects all kinds of metals

» Automatically adjusts the threshold signal with the SAT (Self Adjusting Threshold) system

» Automatic ground balance is powered by 8 1.5 Volt AA batteries.


TECHNICIAL SPECIFICATIONS :

>> Working Frequency: ……………………………….... 6.592 Khz

>>Panelmeter : ………………………………….…………Analog

>> Detection Depth:……………………………….Depths May Vary According to Ground Conditions and Target Size,

>> Ground Setting: ……………………………………….Automatic

>> Threshold Signal: ………………………………………… Adjustable by the User According to the Function.

>> Discrimination:……………………………………………………Detects All Metals, No Discrimination Feature.

>> Weight (Net) :…………………………………..1.3kg

>> Length:………………………………………………………… Adjustable between 115 cm and 135 cm

>> Standal Head :…………………………………….Buluemax 950 (24.6 Cm Diameter)

>> Use Ambient Temperature: ………………… -10 © to 60 ©

>> Operating Voltage:……………………………….12 Volts

>> Rated Current:…………………………………50 mA

[keith777]

The speaker may be blown[/LIST]

yes Carl you are right the speaker is blown. i don't have one to fit so i have bought a replacement one.
do you think that a discrimination potentiometer pot could be added to the board with out any modifications needed done to the board. i think it is the P7 socket slot that is used on the classic board.

cheers........

[Carl-NC]

P7 should be the Disc pot but I don't know what else might be needed to make it work. Not sure if omitting the pot then requires a kludge somewhere.