fitting a new lithium battery to an old original minelab sovereign

[MartinB]

E71 will give you a circuit... his site. http://eddy71.ucoz.net/publ/prostoj_...orov/1-1-0-101

Too much porn on that site

[kt315]

k777
you will be stricken to know that ML super druper firm does not use impulse converter in sov.
you will see 7810 stab there. it's all. i could be deleted it but maybe in future.

[Vadim18]

Too much porn on that site

Just try without porn https://www.eddy.com.ua/

[kt315]

LiPo battery are in a foil pouch. Since that is ~12V means it is a 3S (3 cells).

I've never seen a LiPo in the type of case but it may be possible to remove the case. Just be VERY CAREFUL not to puncture the foil.

guide the knife edge out from the lipo foil/middle. then you never puncture it.

[keith777]

Hi again guys.

i eventually got around to doing something with that lithium battery that i showed in the first of this thread for the sovereign xs. when i took the battery apart there was a lot of empty space at the top of the battery. so i was able to shrink the battery down nicely to fit in the battery compartment.
i have ran it to a problem which was a stupid mistake of my own. the machine is still working. but, yes there is a but. i don't know how i did it. but for some stupid reason when i cut the out put wire end on the battery and wired it up to the - and + wires on the machine i solder every thing up. plus set the heat shrink on. i didn't double check the wires first before doing so. i some how had put the wires on back to front. when i turned the machine on it made a noise on the speaker but not the right noise for the machine switching on. i thought that's not right. i turned it off and back on again and got the same. i thought i am sure i wired it up right. i took the shrink rap back off and to my horror i had wired them back to front. i re-dun the wires again praying that the machine was ok. i turned the machine on. this was without the coil attached and the detector came on ok as it should do. i thought great. i plugged the coil in. give the detector a test and it all seem to be working fine. i thought great. i turned the machine off. then after a few seconds i turned it back on again, but the detector just made a loud humming noise and stand like that. each time i turned it off and back on again it just did the same thing. i unscrewed the coil cable. un-clipped the machine of the shaft. turned it back on again and the detector switched on ok. i plugged the coil back in and the detector is working fine again. i thought, what the heck is going on here. a long story cut short. i have found that the only way that the detector will work properly now. is is you switch the machine on first. then plug the coil in after words?
can anyone help on what the problem is other than. Yes i made a Daft Mistake not double checking what i was doing in the first place.
P.S. you will probably notice that i wired up the external silent search and mutilate tone ID switches also to the back of the case. these were added before i messed up on the battery connection.

thanks in advance guys for any help and advice given........

[Altra]

In case you missed this thread, see post three. It's the same model you have

https://www.geotech1.com/forums/show...991-Sch-matics

[keith777]

thanks for the link Altra. i wish i new more about electronics to be able to to fix the problem. maybe someone could show me were on the board i need to test for a fault and how..........

[Altra]

If I read your post correctly you basically connected the battery in reverse? So you'll want to check the power supply.

The power supply part on the board is where the the three large electrolytic capacitors located. I remember Q7 BS170 mosfet would cause problems and u24 a TLO62 could also be damaged? Maybe one of the guys from the schematic thread can chime in.

[keith777]

i have this image of a board which i think is like mine. i could take a photo of my board if need be..........

[keith777]

please could anyone help to assist me on testing and finding the main fault..........

[Carl-NC]

The problem is obviously a loading issue caused by the transmitter when the coil is connected. So the first place to look is at the power supplies, especially the switcher that creates -5V. Zed's schematic also shows a 2.5V reference that goes to the TX, I'd look at that. The TX has what looks like a snubber and maybe energy recovery circuitry that is all tied into the timing but without a serious deep-dive I can't say how any of it works.

It is unlikely anyone will be able to point to a part and say, "Replace this," and you're done. This will require an oscope and some figuring out. Fortunately you have 2 states that you can compare.

[keith777]

i have just taken a photo of my Sovereign board and it does match that of the one that i put up in the other post.

[Altra]

Do you have a voltmeter?

Attached photo of test points

No coil connected turn on power and use your finger to see if any of the marked parts are warm or hot. If so replace

You can check voltage U24 TLO62 pins 4 and 8 should be equal to the battery voltage 11 to 12 volts if using a lithium.

U24 pins 8 and 1 should read about 2.5v

U21 pins 11 and 4 = 10v

Do any of the large electrolytics have bulging tops or swollen? Can't tell from your photo.

The three (yellow/orange) tantilum capacitors need to be check for cracks. May have been damaged by reversed battery

Try these test

[Carl-NC]

I'm sorry, when I replied I had SD2000 on my mind and was looking at those schematics. Follow Altra's advice.

[keith777]

Do you have a voltmeter?

Attached photo of test points

No coil connected turn on power and use your finger to see if any of the marked parts are warm or hot. If so replace




You can check voltage U24 TLO62 pins 4 and 8 should be equal to the battery voltage 11 to 12 volts if using a lithium.

U24 pins 8 and 1 should read about 2.5v

U21 pins 11 and 4 = 10v

Do any of the large electrolytics have bulging tops or swollen? Can't tell from your photo.

The three (yellow/orange) tantalum capacitors need to be check for cracks. May have been damaged by reversed battery

Try these test

[ATTACH]58036[/ATTACH]

[ATTACH]58037[/ATTACH]

thanks so much Altra for the help.....

i checked them areas that you pointed out with the multi meter.
U24 TLO62 pins 4 and 8 give 11.50v
U24 pins 8 and 1 give 2.41v
U21 pins 11 and 4 give 9.84v
i couldn't feel any components any ware on the board that were warn or hot.
the large electrolytics have no bulging tops or swelling to them.
the tantalum capacitors have no cracks that i can see. plus i cannot see any physical damage to any of the other components on the board.