Dell C400 recharge problem

[glyn]

I've been googling for help with a Dell laptop power problem and there seem to be some knowledgeble people on this forum. Unfortunately, my problem does not seem to be the same as in the previous Dell thread.

The laptop is a Dell C400. It works fine with either a charged battery plugged in OR the power adapter but not with both connected at the same time. When the power supply and battery are plugged in the adapter immediately switches itself off. I assume this is some sort of failsafe but I don't know what would be triggering it. The power supply is definitely ok as different supplies all exhibit the same behaviour and I have another working C400

I've dismantled the laptop but I can't see any loose connections or anything obvious and am not sure how to proceed. It is quite frustating having a fully working laptop which can't recharge its battery.

Does anyone have any ideas as to what might cause the power supply to shut down? It may help me narrow down the problem.

Thanks

Glyn

[arneson]

Re: Dell C400 recharge problem

Glyn,
I'm one of those with the 'other' dell power problem.
If your still inside be sure to totally clean out fan and rethermal coat proccessor.
You may carefully resolder power jack or just to be sure you may replace it, it's finicky.
I want to think your issue is with the bummer dell battery problem, what do you see in the bios? What bios version? page 5? show.
I've seen, charger none, charger unrecognized, and charger bad.
Your service tag lookup may also be a clue. The PA series adapters were made by more than one company, Liteon and Delta, which was yours?
Nothing I say may be helpful because I have not been successful.
Spent a lot of time and money and have a collection of dead dells.

[glyn]

Re: Dell C400 recharge problem

Thanks for the reply Jim. I'll have a go with resoldering the power jack.

I've tested it with different power suppliess and batteries because I have a second C400 (ebay purchase after the first one broke) so it isn't a battery or supply problem. I'll have a try with the bios and see what it says.

Anyone else got any ideas?

[Rainbow]

Re: Dell C400 recharge problem

The failure is probably in the battery charging circuit. There should be a chip that controls battery charging somewhere - and some transistors and other components around it - I'd check that.

[arneson]

Re: Dell C400 recharge problem

http://cgi.ebay.com/DELL-Latitude-D4...QQcmdZViewItem

This is the dock for that lap, It has a seperate power feed and may serve as a work around.
I don't see a lot of the D44's with problems, like the 1150's have.

[glyn]

Re: Dell C400 recharge problem

Hi again.

I've had another chance to get inside the laptop but I can't see anything obvious. In fact, I'm not even sure where the chips responsible for the recharging are. Can anyone identify them from the attached picture. The only chip that looks vaguely darker (by which I mean not shiny clean solder) is marked with the red arrow. The text on that chip is 4542 SSAD (delta symbol) w28a. The big chip to the left is just an inductor.

I've not tried resoldering the power jack since it looks fine and I can run the laptop off of it without any problems. However I may try this anyway if I can convince myself it may be responsible.Does anyone know what each pin on the supply does? On the supply they are labelled +,-,NC and I don't know what NC is. The supply is shutting down because it is detecting a short somewhere. Any tips on locating it?

Thanks for the tip about the laptop dock. I have a C400 but the principle is the same so I might get one.

Glyn

[arneson]

Re: Dell C400 recharge problem

I was able to fix Dell laptop mainboard only after getting a working board next to it for direct comparison.
Sorry this may not be helpful, but I ended up in total, with two dead boards and two working complete laptops. One to return to owner and one to sell.
I'm selling toasted boards as well since I bought them as is, not working, just to experiment.

[mutant]

Re: Dell C400 recharge problem

I also have one with the charger shutting off. I updated the bios to A12 and in a few weeks it quit charging the battery. I have another c400 mainboard using A11 and have no problems.
Here is what has been updated:

The following modifications were made to the A11 BIOS to create A12:

Issues Fixed:
1. Fixed issue in which the system continues to report the status
of the original battery if a battery swap is performed while in
Standby.
2. Optimized the battery charging algorithm.
3. Removed the SMBIOS Type D4h audio tokens since they do not have
any effect. The audio mode is always "full duplex".

Look at number 2. I haven't gone back to A11 yet.
Before it died it sounded like a high pitched whistle and it changed in pitch constantly.
I have taken it apart and there isn't any loose soldering or other connections.
I originally thought it was the battery. So I switched batteries. Same problem.
Lucky for me I don't have to rely on the battery so I have it plugged in all the time running folding@home 24/7.

So arneson what did you do to fix the laptop board?

[arneson]

Re: Dell C400 recharge problem

So arneson what did you do to fix the laptop board?

I'd love to give a simple answer to you but it was a costly bitch.
Heres the gist of it.
Four units, two complete,one smashed screen, one no screen no keyboard.
All of these are 1150's, four good batteries, four power bricks not all the same.
These laptops did not recognize the power supply even intermittantly but they powered off the battery until dead.
The best of the four worked with a brand new power brick, I imediately went to the latest bios and I'm folding and posting on it now.
The second successful one needed The jack replaced which I stripped from fourth board, again flashed new bios.
The third board only blinks lights, fan runs 2 seconds and will not start. Since the screen is ng, keyboard is ng and main board is ng this is in a junk box.
The fourth had a pin hole blown in the power control chip, also in junk box.

So bottom line with my dell fiasco was power brick first, resolder jack second,
get new bios when you can. Lesson learned, do not let any laptop overheat.