help needed with old detector

[kt315]

golden pins... when it was... pnp type, high HFE, 200mHz.

[homefire]

Yep PNP . Most new detectors use something like the MPSA-13 or the like.

[dbanner]

2N4403 connected to coil, not audio. Audio somehow is on smaller board maybe, since i see green wire connected from smaller board to headphone jack. We need some more pics of wiring between boards and controls etc. otherwise can't make heads or tales. This metal detector may have quite unusual design. Could be nice to reverse engineer to see what's really going on. Please provide more pics of internal wiring.

[keith777]

now you are all talking double dutch to me now i have dyslexia quit bad. so that doesn't help much either. i will take some more pics later. not quit sure what to take as i have already taken quite a few now.

[dbanner]

We need pics of wires coming from coil cable attached to mainboard connector strip and better pics of all internal wiring. The idea is for us to be able to see specific wires and where they are connected so we can work out generally how this detector is put together. Then we will know where to look for the fault. If you know how to use a VOM to check for continuity then its easy to check each transistor and diode. There are five PNP transistors 2N3638A(the four black top ones on mainboard and one on smaller board), one 2N4403 PNP( the small one on mainboard) and another transistor on smaller board which i cant see the number on it, plus a few diodes. All these components are easy to check for integrity with a multimeter(VOM). Even you can do it without much any knowledge of electronics.
I think this metal detector is quite rare and worth fixing, but this is just my opinion.

[kt315]

load pls pic of bottom board side but not in perspective you did, in direct projection. i wll do lay pic.

[dbanner]

O.K I need better pics of wiring in this area only.

[keith777]

We need pics of wires coming from coil cable attached to mainboard connector strip and better pics of all internal wiring. The idea is for us to be able to see specific wires and where they are connected so we can work out generally how this detector is put together. Then we will know where to look for the fault. If you know how to use a VOM to check for continuity then its easy to check each transistor and diode. There are five PNP transistors 2N3638A(the four black top ones on mainboard and one on smaller board), one 2N4403 PNP( the small one on mainboard) and another transistor on smaller board which i cant see the number on it, plus a few diodes. All these components are easy to check for integrity with a multimeter(VOM). Even you can do it without much any knowledge of electronics.
I think this metal detector is quite rare and worth fixing, but this is just my opinion.

this is the only multimeter that i have which i only know how to test voltage and testing wire for brakes.

[kt315]

reconnect negative black probe on COM/MON socket.

[dbanner]

Yes. This is multimeter. Testing wire for brakes is what i mean by "testing for continuity". Setup your meter as shown in pic.
The selector switch is set as shown, the black probe connected to COM as shown.

With multimeter setup like this, you are now ready to test for continuity or test diodes and transistors.

[keith777]

thanks guys. i really appreciate the help.

[keith777]

O.K I need better pics of wiring in this area only.

i have done a drawing of the wiring on the inside. would this help you any better?

[kt315]

ignore?

do i have to initialize your answer??? i need a pic of pcb back side.

[keith777]

kt i haven't getting around to it yet. give me half an hour and i will take it out and take a photo for you......

[keith777]

KT is this any good for you.....