5500 Service Manual And Ccfl Inverter Question

[t.james]

Hello everyone,

I'm new tothis forum but, I've been watching it  for some time.

I've got my sl-5500 recently and would like to play with it abit.
I'm looking for service manuals (I'now you have them guys) and specialy looking after any info about CCFL inverter.

It is writen in OESF FAQ about power consumption:
Backlight at Full about 340mA
And that's much!

I've found this page:
http://www.spritesmods.com/?art=ledbl&page=1

Guy changed backlight in HP Jornada and cut power consumption from 125mA to 90mA using white leds. In his PDA CCFL tube is much longer than in Z so he had tu use 14 LEDs.

I'd like to do something simillar for Z I think that beacuse of shorter CCFL in Z I'll need less LEDs and therefore (should) acheive even lower power consumption! Not mentioning that proper LEDs should give brighter light than (mine) CCLF.

As can be seen here: http://www.tekprosystems.com/zaurus/internals.htm (last photo)
Inverter is connected with MB using 6 track "ribbon", but it seems that tracks 1 and 2 (counting from left) conduct the same signal (take a look at track layout on PCB)

So my gues:
(1,2) , 6 - Power (Vcc,GND)
3,4,5 - control

Now I'd like to design LED control that'd be compatible with original inverter especialy  dim control the only problem is I don't know how Z controls dimmming.
As far as I know there are two most common dim control options used in CCFL inverters:

- Analog (voltage) control
- Digital (PWM) control

I'm looking for any info about how Z control dimming and/or meaning of those 6 lines which are connecting MB and inverter.

So if someone has some knowledge about it please let me know.

Cheers,

James

[wayne]

It is writen in OESF FAQ about power consumption:
Backlight at Full about 340mA
And that's much!

This depends on the type of tube used and voltage driven. It also depends on where you measure.

I'd like to do something simillar for Z I think that beacuse of shorter CCFL in Z I'll need less LEDs and therefore (should) acheive even lower power consumption! Not mentioning that proper LEDs should give brighter light than (mine) CCLF.

Now that entirely depends on the type of LEDs you use and their efficiency. There are many types of white LEDs with different power consumptions. Be careful to select LEDs that will be efficient if you want to cut on power consumption.

Now I'd like to design LED control that'd be compatible with original inverter especialy  dim control the only problem is I don't know how Z controls dimmming.
As far as I know there are two most common dim control options used in CCFL inverters:

- Analog (voltage) control
- Digital (PWM) control

Since the Z can "turn on" a CCFL tube at the lowest intensity, my guess is PWM. Analog dimming works for CCFL tubes but not with as good results. Typically you'll need to turn on the tube at full power and then lower it to the desired level. With PWM you wouldn't need to do that.