help with lm317t regulator circiut

hi, i know this is basic stuff but i have been away from the soldering iron for quite some time.

i live in the middle of nowhere and mainly use solar power/lead acid. problem is the stupid switch mode power supplies for the laptops are all fried one by one, 12v and 220v. it happens. but now i have none.

what i do have is an lm317 and a few 2n3055's and my 11.5v-14v solar/battery system. the silly laptops want 9.5v and wont accept a couple of hundred mV either side.

i built the standard circuit one would expect and the lm317 is stable but the output from the 2n3055 (2x in parallel) drops when i apply the load (up to 2 eeepc701 netbooks).

is there just not enough overhead of volts to regulate effectively?

now is not a good time to revise my theory, i need a working circuit and fast, and it has to be with these parts as i cant get anything else.

please help me, its boring as hell here with no music or proper internet access or movies. the netbooks run my projector and stereo, no other media fit devices here, just this old thin client running linux on a 300mhz cpu! if that gives up ........

Can you upload a schematic? I would like to see how you are using the 2n3055. How much current do you expect that you need? Also do you have any bulk capacitance that you can put on the output of you circuit?

sorry, but i cant send images and dont have a link. heres a basic rundown,

1.4k from adjust to ground
220 from adj to out
10 from out to final output from emitters 2n3055
out conected to bases of 2n3055

100nf from in and out of 317 to neg rail
100nf final out to neg rail

2n3055 x2 in paralel

that was the basis....

then i tried removing the 10r... no difference
then moved 220r from adj to adj-final output.... no better.
then i removed the 220r and linked adj straight to final output rail.. no better

the laptops draw between 100ma and 2 amps each original smp rated 2.5a

the power tr's bolted to heavy ali heatsink/case from a cb amp, (+chassis )
lm317 is clamped on a mica sliver with heat paste. nothing gets very warm.

hope that makes sense cody, make my day so i can watch that xmas episode of doctor who!

i have a few electrolytics, 1000mf or about that, can scrap some boards if needed

willing to start again from scratch for a circuit that will definitely work. i have:

2x 2n3055, 1x lm317t, enough resistors to make any value i dont have, capacitors but not many power grade (remember im using 12v dc input), and several 1n400x diodes from scrap gear (may help drop a few volts.)

i need the output to stay +- 200mv of 9.5,

input current available is 100+ amp from lead battteries, voltage range is from 11-14.5v.

output current i hope to be 0 to 5 amp without affecting output voltage.

It is highly likely that your regulator doesn't have enough headroom and that's why it drops out. You need a low dropout linear regulator so go look one up on the Web, something capable of say 3A with Vce < 1V or so. You can't find one make one. They are simple & cheap. There you go.

By the way the electronics, etc, are not stupid because they do what Mother Nature has intended. You may not like it but you can become the master of the situation if you simply take time to understand what is going on & choose to let Mama work for you.

You can use about 5 parts, $1 in cost to make your regulator. Slam dunk.

Hi ED,
I have a other solution.
The EEEPC 701 does work from 12 V see.
"klick link(eeepc 701 on 12v)":http://wiki.eeeuser.com/hardware_power_consumption#using_a_12v_battery

i used mine several times during long car travels on that way.

just make sure that you are not charging the 12 volt battery at the same time.
If you have a old CB unit you will find a few power diodes to drop voltage a little and protect.

And yes my EEEPC is my little life line to the civil world.

Update:

see below link
"click link to ASUS(asus)":http://eeepc.asus.com/au/accessories1.html?n=2

It is a ASUS original power supply as well for the 700 serie and the output is 12v 3Amp.

Just make sure not to feed 13Volt and more.

ok i revise the use of the word stupid from applying to smpsu's to only applying to modern economic theory, ie; build it as cheap as posible and when it fails we can sell another unit.

also i draw your attention to the fact that i live 'in the middle of nowhere' ie; i dont have radioshack ten minutes down the road. im snowed in at the moment and when it thaws i still have a 2 hour 4x4 trek to the nearest village where i will be lucky to get basics like wood, petrol, beer, hammer. mama nature is firmly in control.

as for dropout, well really that was one of my original questions, trouble is how to get round it. practical circuits please only!!! i have the parts listed, also a bag of general purpose npn transistors, about 50 glass valves, and a multimeter.

im not sure if the eastern europe model 701 are different, but i can assure you that these ones (i have 3 for the family) do not like 12 volts or anything near. they go to protection mode where the charge led flashes but wont suck power. the last charger to die was a car charger and it failed high, ie the output went up to the full 12. maybe the usa domestic market demands better input voltage acceptance. the 701 is very popular here as it was the first netbook normal bulgarians could afford (just about afford) but that was 5 years back and the stores in the bigger cities dont carry spares, just try to sell a wrong charger thinking im an idiot, plus here you cant take bad products back for a refund, they will laugh in your face.
its a different world, but we do have an amazing amount of freedom, low taxes, better gun laws, not the nanny police state in the uk where i came from.

Make sure that the battery is not charged at the same time. use a diode as protection and drop a little the voltage or use two in series to drop more.
I have the same if my engine runs it does not work because of the charger but as soon the engine is off, the EEEPC is charging normal.
The same model is sold world wide with only a different cable and or battery capacity.

OK, had some fun with this -- and now the disclaimer: Analog design in NOT my forte, but, since no one else has offered anything like this, here it is:

The CircuitLab link:

* https://www.circuitlab.com/circuit/c2s896/eeweb_9_5vregusing2n3055s_02/

and a PNG is attached.

R7 represents your laptop(s). This is not the most efficient circuit, and it will loose _regulation_ slightly above the minimum specified voltage (11.5V). I italicized _regulation_ because, the regulation on this thing isn't the best, and possibly might not conform to your specification of "a couple of hundred mV either side".

With a PNP power transistor I could, probably, make a low drop out version of this that would work down to 11.5V. It _will_ work down to 11.5V if Q4 is removed, but R4, R3, R6, R8 & R9 would all have to be divided by around 30, which would put quite a drain on your battery (i.e. even more inefficient!).

Also, I left it to you to work out the resistor wattages.

Perhaps one of the analog designers, out there, will jump in and spruce this up

Try this.

BTW: regarding the fried switchmode supplies: perhaps due to stepped sinewave approximation in inverter? Not sure if that is even a factor--I have no experience with this, but thought I would throw it out there.

This circuit may be similar what you want.

I also using linux-ubuntu on thinkpad x100e.