Minelab SD2000 problem

[mitecho]

Hi All
I just purchased Minelab SD2000 , apparently it has a problem with low sensitivity . The detector doesn't have any mods done and looks like never been opened. Tried different coils, even a new one. Just wondering if anyone has any experience with this problem and can help. Never done PI machine before and wondering where do i start from ? Will remove the paint and start to measure timing and transmit trains (samples) according to the schematic diagram, will this help somehow and give me any idea or the problem is more likely to be in the receiving section?
Cheers
Dimi

[kt315]

Will remove the paint
--
try dissolver for oil paints. all resistors values you can measured not desoldering them. but capacitors
in smd you need to desolder. also you have to check electrolitics on ESR using ESR tester.

[ivconic]

First try to look up for most trivial causes, like power cords connection and connector.
Is there enough current flow from battery to detector and similar.
Than check coil cords and connectors too.
Use oscilloscope to monitor what's happening at coil, RX front end etc.
There is a chance that it is something most trivial and stupid that you can't imagine.

[mitecho]

Will do thanks, however before start removing components like to trace everything possible to localize where the problem is.

[mitecho]

Power cord and all connectors ok, will check the current , what should get from measuring RX front ends?

[ivconic]

Will do thanks, however before start removing components like to trace everything possible to localize where the problem is.

Sure!
I had similar problem with SD2100. Very "faint" behavior and low sensitivity.
At the end it turns out that it was lose power cord and very small current flow because of that.
So detector was not supplied with enough current from battery.
Most trivial case that i remember. But it was not easy to locate it because symptoms were pretty confusing.

[ivconic]

Power cord and all connectors ok, will check the current , what should get from measuring RX front ends?

First check the pulse from TX and than check the signal at RX front end output. Is there any noise, with and without detection etc.
But first check the current with ampere meter, also in both cases; with and without detection.


P.S.
Maybe you don't have this:

[mitecho]

First check the pulse from TX and than check the signal at RX front end output. Is there any noise, with and without detection etc.
But first check the current with ampere meter, also in both cases; with and without detection.


P.S.
Maybe you don't have this:

Thanks will check these out and let you know.

[kt315]

ok. can you send me pics of inside on board and pots on email? in exchange i send all files on this bear.
(you will be not needed to find up the files in the forum)

[kt315]

Will do thanks, however before start removing components like to trace everything possible to localize where the problem is.

you are right. while schematic is drawn but there is not full info to begin to copy. its problem.
so having full info people will get new life start.

[mitecho]

ok. can you send me pics of inside on board and pots on email? in exchange i send all files on this bear.
(you will be not needed to find up the files in the forum)

I've sent you an email

[mitecho]

But first check the current with ampere meter, also in both cases; with and without detection.



:

The current with no coil is 120mA, with coil with detection 540mA ,is this ok?