MP800 will not charge or power on

Hi everyone,

First post here but I have been browsing for a few weeks; great website. I bought an MP800 from Rich on eBay (no AC adapter or battery) and it was working fine with a universal adapter. I went on vacation last week and while on vacation received my new battery from alancomputech. When I got home today I inserted the battery, plugged in the AC adapter, and nothing: the charging light did not light up and I could not turn the unit on. I opened it up (not at all difficult and I would be happy to provide guidance to anyone who needs it) and poked around a bit with my multimeter; the power seems to be getting to the motherboard, so the connector for the AC adapter is working fine. Any ideas as to where the problem could be? Also, while I had the unit open, I checked the backup battery and it has 1.60 volts; this should get back to 3 volts when I get the charging working and charge the main battery fully, correct? Thanks in advance.

-Erik

Edited by Upgraded MP780 2006-03-20 5:10 AM

Try a hard reset before inserting the battery to charge and see what happens. If nothing, then push the soft reset button and see if that does anything...

If not, then remove the battery and see if it runs off the ac...if it does it is possible there is something amiss with the battery.

Rich

Hi Rich,

Thanks for the suggestions; I have tried all of the above and none of them woks. Any other ideas?

-Erik

What's your multimeter show when attached to the battery? Any voltage at all? Open circuit?

What power supply are you using now Erik? What is the voltage/current rating? If it doesn't supply the rated current, the device will not turn on with the battery in place because it is too much of a current drain to both charge the battery and run the unit.

Send me an email with your normal email address and let's see if we can figure this out....

Rich

Edited by Rich Hawley 2006-03-20 3:58 PM

12V 800 mA is enough for my mp800 without a battery (will get a battery for it soon though - hope it will charge when the unit is off)

IIRC the 800 series needs 2.6 amps to charge and power the unit. According to my MP890 adpater anyway. I have a 800ma adapter I mean to try for a power source for my 800 but I'm not expecting it to charge the battery.

it doesnt matter what is written on the adapter itself.
you know the j720 adapter says 2 A, and i could charge its battery with a 500 mA adapter, while unit was on and at full screen brightness... when i tried to use the modem to browse, that was when my adapter gave up on charging i lowered brightness and it again charged OK.

wallythacker: Don't know why I didn't think of checking voltage with the battery in; I can do that this evening. However, I doubt that the battery has any charge in it unless alancomputech charges them.

Rich: The adapter I have been using is a universal from RadioShack. The voltage is adjustable in whole volt increments (12, 13, 14, etc.); I was using it at 13V without the battery and that was fine. I think the adapter can output 80W or so, so if I understand correctly, that should amount to plenty of amps. I checked the adapter with my voltmeter, and it seems to be fine. I also rigged the proper tip with a TI laptop adapter I bought on eBay which outputs 13.5V, 2.77A; that doesn't work either.

Rich, I would be happy to discuss via email (just changed my setting to make it viewable) but I think it might be a good idea to keep this discussion on the website, especially as people may be exploring DIY AC adapter solutions for their MP800s.

Thanks to all of you for the help; I can't tell you how much it is appreciated.

-Erik

What is the current output on the adapter...300mA, 800mA, etc? Does the 800 work without the battery in place?

Rich

I'd expect some voltage from the battery. Aren't lions killed if you discharge them to nearly 0 volts? I've read contradictory info on this.

The adapter should be supplying 2.6 Amps, same as the original MP800 adapter. No, doesn't work without the battery.

Doesn't work without the battery? Bad news I believe as it should work on the a/c adapter alone. Send the unit back to me and I'll swap it out with one that I was holding onto just in case I had sent anyone a faulty unit....

I checked these things out as well as I could, made sure all the ports worked and the units charged a battery fine, the digitizer, etc...but you never know with used equipment what gremlins there might be...

Rich

That would be awesome, Rich. I will send it in the next couple of days.

-Erik

Got it today, will put the replacement unit in the mail to you. It appears that the power jack somehow got broken. Runs perfectly off the battery, but is not getting power from the a/c adapter to the unit. I was able to jump the current directly from the adpater to some parallel solder traces on the circuit board and it then worked fine off the ac. Just the jack itself went bad somehow.

I've been wanting to have some reason to pull the jack off one of these things and mount a standard phone type jack instead...now I have it.

Rich