MicroLogic ML 250 GPS repair help

[David Hills]

Hello<br /><br />Does anyone know if a MicroLogic 250 ML should<br />still switch on if the internal battery was completely flat or removed?<br /><br />I am trying to repair one and the CR2430 internal 3 volt battery is dead.The unit will not display anything when I press the on button.I'm applying external 12 volts on pins 1 and 2 (red + on 1 and black - on 2)on the rear connnector.<br /><br />If its very "sick" there is not much point in buying a new battery which cost about £10 here.<br /><br />Many Thanks<br /><br />Dave Hills

 

[SlowlySinking]

Re: MicroLogic ML 250 GPS repair help

David, if you haven't done so already try removing the dead battery and see if it powers up.

 

[David Hills]

Re: MicroLogic ML 250 GPS repair help

Thanks SlowlySinking I've tried that but know responce. Someone has sugested I now short out the internal battery connections so the memory circuits are still powered.The internal battery was not open circuit but was only reading point .2 of a volt. What do you think?<br /><br />Thanks Dave

 

[SlowlySinking]

Re: MicroLogic ML 250 GPS repair help

Hi David, with .2 volts there's no doubt the battery is dead. I checked the web and this site in England has the batteries for 1.5 pound each.<br /> http://www.mdsbattery.co.uk/shop/productprofile.asp?ProductGroupID=833 <br /><br />Question, was the unit working and then just stopped? If so then replacing the battery should fix the problem. There is the possibility the unit needs the 3 volt battery to work at all, no way to be sure unless you have the operation manual which may indicate that. If you short out the CR battery terminals without the normal 12 volts operating power attached you won't damage anything since there is no power, I doubt it will damage anything since the CR memory battery doesn't connect to the 12 volt circuits. With 12 volts applied it may damage the unit but then it isn't working so what do you have to lose, I use that principal whenever I fix something. In the old days with tube (valve) equipment we would bypass the fuse and look for smoke, good luck.

 

[David Hills]

Re: MicroLogic ML 250 GPS repair help

Thanks slowlysinking<br /><br />I've odered some battries.The unit was working fine.I thought it would be unlikly the unit would not work at all because of a flat internal battery as this would seem to be a bad design feature. I 've been investigating with my ditigal volt meter and the main voltage regulator chip ouput goes to 5.3volts when you press the on switch on the front pannel for about half a second then back to zero.May be the unit powers up detects a fault with the 3volts and switches itself off again.I guess I will know when i put the new battery in!<br /><br />Thanks for your help<br /><br />Dave

 

[SlowlySinking]

Re: MicroLogic ML 250 GPS repair help

Hi David, that sounds about right, seems to me this is a GPS, if so the unit apparently has a safety feature that prevents it from operating with a dead memory battery, this way the memory coordinates and other data can be trusted. Glad to help, good luck, Ken

 

[a7878]

Re: MicroLogic ML 250 GPS repair help

If this was the battery that powers the GPS a good way of solving this dilemma is to test the battery independently of the GPS device. You should be able to do so by connecting the battery directly to 5V to a relatively high impedance charger, like an old cell phone charger. That way you can see if you can get the battery voltage to get anywhere close to 3.7V. If the GPS does not power on when a battery with 3.7V is connected, the problem must lie elsewhere (a defective logic board is likely). If you can not get the battery to at least that Voltage, the battery itself is defective. However you are mentioning the battery the supports the Ram when the device is turned off. Very unlikely that the fact that this battery is empty keeps the device from booting up, there will be an additional problem. Some GPS Repair places carry boards for the MicroLogic.