Metrotech 220

[metalfoot]

Hey all, I was at the "Junkmans" corner rooting through potential treasures when up high in a moutain of junk...er I mean potential treasure I saw an old looking part of ble headphones sticking out and decided to invesigate. Well, after pulling out the wires to the head phones it led me to a Metrotech 220 in very good cosmetic shape. Had minimal difficulty finding a battery at Battries Plus. Well at their shop the battery produced a needle jump and a tone. I noticed the needle stuck and saw it was due to the plastic lens pushed in on to needle so I took it apart to fix this and now I can not remember which of the two meter wires went where. I have tried both possibilities and bot produce odd results but neither seems right. Does anyone have this same unit that they could send pic of how it should be? I did get an electronic copy of user manual from Metrotech but that was minimumaly helpful. If anyone has wiring diagram that would be perfect. Thanks for any help or advise. TTFN.

[Rayman]

Doubt you'll see this since the post is three years old. I have a working 220A.

[metalfoot]

Hey Rayman, I got it working (took me a little while to understand that the plug on the headphones turned it on. I was actuall lucky enough to get a copy of the manual from the Metrotech, in fact they still will work on them and have replacement parts. Thanks.

[Rayman]

You wouldn't mind sharing any documentation you have on it would you? I've done some searching but come up empty handed.

[docholiday]

Metro tech

Hi Rayman
Just as a note of interest to you--the first MD I owned was a METROTech. Found a lot of minie' balls with it--40 years ago. Good luck!!!!!

[Rayman]

I live in Fredericksburg, VA and surrounded by civil war battlefields. Whoa to the one who get's caught in one with a MD.

[sdesic]

Do you still have a MetroTech 220 detector ?
I have a faulty one and need to place one wire to somewhere... brown wire is disconnected.

[Rayman]

>sdesic... Yes, I still have it. If you could include a pic that would be helpful. But I can check mine tonight and look for the brown wire and see where it's connected. Do you have an operator's manual? I'm still trying to track one down.

[sdesic]

Rayman

I will post few pics in 15 minutes.
i have no manual ... sorry, if I find it I will post it here.
I got detector and speaker box.

Thank you.

Regards
Sinisa

[sdesic]

I am posting pictures of Matrotech 220 A
Brown wire is loose.
I guess it needs to be on pot by looking at connections ...







Don't know how to open MD head enclosure of this type.

[Rayman]

sdesic

The brown wire connects to the potentiometer on the end tab. That same tab should also have a bare wire that connects to the headphone jack. I've attached your pic and highlighted the correct location for the wire.

[sdesic]

Rayman,

Thank you !
I assumed so... I will try that tonight.
I have also problem in MD head - something is loose...

[Rayman]

Sinisa

Good luck with the repair. As for the MD head, I doubt there is anything wrong with it. It is a simple inductive coil consisting of a copper wire wrapped around a non metalic form.

Rayman

[sdesic]

I just tried it with brown wire connected ... no luck
Speaker box seems to be problem No. 3
It has some kind of electronic circuit in it but no sound from plain audio device - gives 11k6 resistance on connector.
Will try headphones but I think this device needs piezo headphones - or hi resistance with transformer.

I will try to measure resistance of coils - 1 connector - 3 pins (big stereo phones connector)

[sdesic]

Tested resistance of coil - it is on two pins ... third is not connected I think
about 3 Ohms ... 66 uH (micro H)

Opened top of detector head - by removing "radioactive" logo
under it it is a hole ... you can see peace of (probably) aluminium (3-4 cm long)
which is connected to button on top which is sensitivity button
(it rotates this peace of metal inside and disturbes magnetic field ...)
and I discovered one more loose peace of aluminium
which is flying around inside head...