OESF Portables Forum

Everything Else => Sharp Zaurus => Model Specific Forums => Distros, Development, and Model Specific Forums => Archived Forums => 5x00 Hardware => Topic started by: jalex on August 31, 2004, 09:44:30 pm

Title: 5500 charging circuit
Post by: jalex on August 31, 2004, 09:44:30 pm

I have a 5500, serial 27030301.  It runs and boots from battery.  However, I cannot charge the battery, even when I turn charge on from Diag menu.   The AC adapter that came with it, Phihong PSC10A-050 says it is 5V at 2A current.  However, when I test it with a multimeter I get 3.8 Amps, at 5.01V.   I suspect this AC adapter may have damaged the Z, but no way to know since I received it second hand and the previous person seemed to think it worked or something.

I am getting very low volts/amps from the battery terminals, even when it was running with the ilght on.  I can get to the diag menu on battery, but AC doesn't seem to register.  I do see the volts cycle on the middle connector of the battery connections, which is good, since it uses a little cycle to detect the battery.

Without AC registering or charging, I cannot flash the ROM.    

I was wondering if someone had a link or document with the voltage/current of a good, healthy zaurus on hand.  I think this would be helpful.    

Also, where is the charging circuit on the Z and how do I identify the components.  The resistors, transistors and capacitors all look very different from the big old ones I am used to seeing.  Some of the components even have numbers on them.  

I will probably end up sending it this Z tio Romax in Texas.  I got their info from the 1-800-be-sharp messages.  Unfortunately, I can't help but believe I am screwed and it will cost 100+ dollars to fix.

Before I sell it for parts, it would be absolutely awesome if someone with a healthy Z has some info on what to expect from it and what may be possible.

Thanks.

Title: 5500 charging circuit
Post by: zbones on September 01, 2004, 04:09:46 am

See the bottom of this page :-

http://www.tekprosystems.com/zaurus/internals.htm (http://www.tekprosystems.com/zaurus/internals.htm)

Let us know if you get it working.

Peter

Title: 5500 charging circuit
Post by: omega on September 01, 2004, 04:56:59 am

how did you measure 3.8 amps at 5volts?   Amps is only capacity... it's not important as long as you have enough. Your Z will only take what it needs.

Title: 5500 charging circuit
Post by: jalex on September 01, 2004, 05:44:40 am

I measured current with a multimeter.    When you initially put the AC adapter into the Z, it will cause a very quick short - not sure if this is normal.  Continuity tester showed the same thing - a quick beep just as you hit the connectors.  If this is normal, and the current is too high, damage is possible, I would think.

My connectors are fine.  I get close to 5V at the terminals under the keyboard and at the AC jack terminals.  The terminals measure the same if I am using the USB docking cradle or AC directly.

Title: 5500 charging circuit
Post by: dansawyer on September 01, 2004, 11:43:38 am

I also have a Z with a charging problem. The charging circuit seems to function. However the s/w control or sensing circuit detects the battery is fully chrged almost immediatly after it starts to charge. I have worked part way through the diag menu. Has anyone sorted out how that works?? There is a setting in that menu that turns on charging. That actually works if forced.