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Another crazy portable hack of mine
- Thread starter techknight
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techknight
Well-known member
Out of the box its huge, it has a monstrous transformer in it.
techknight
Well-known member
Well it was a large A4 Sheet so it came with that big inverter.
But.... Because I cut it down, it should be much better now.
But my goal is to make a small expansion card that goes into the ROM slot. I will use a CPLD to decode the address bus to allow the control panel to work, but have a small MCU on it to act as the inverter controller. Ill use its PWM output to drive a mosfet, into a small transformer at 400Hz. the PWM will be the brightness control.
But.... Because I cut it down, it should be much better now.
But my goal is to make a small expansion card that goes into the ROM slot. I will use a CPLD to decode the address bus to allow the control panel to work, but have a small MCU on it to act as the inverter controller. Ill use its PWM output to drive a mosfet, into a small transformer at 400Hz. the PWM will be the brightness control.
CC_333
Well-known member
This is SO neat!
This makes me want to get a non-backlit Potable just so I can get one of these installed in it! It looks brigher and better than the backlit's old CCFL lamp, too (which, besides being old technology, likely hasn't aged well).
That being said, I wonder if one of those EL things can be retrofitted into a backlit Portable, using the original control circuitry?
c
This makes me want to get a non-backlit Potable just so I can get one of these installed in it! It looks brigher and better than the backlit's old CCFL lamp, too (which, besides being old technology, likely hasn't aged well).
That being said, I wonder if one of those EL things can be retrofitted into a backlit Portable, using the original control circuitry?
c
unity
Well-known member
^ It should be possible, sorta. All it comes down to is voltage and the voltage curve. The original, let say, ran at 12v but by 6 volt it may be off. With EL, which operates at a higher voltage, there may be an issue with the dimming "curve".
Just guessing though, you guys know more about this stuff that involves magic smoke and unicorns.
Just guessing though, you guys know more about this stuff that involves magic smoke and unicorns.
CC_333
Well-known member
Yeah, I'd imagine the EL panel would need, at a minimum, some sort of "glue" to make it compatible with the voltages and curves of the old backlight circuit. Then what about the original CCFL tube and reflector? Remove them? A backlit LCD is structured differently from a non-backlit panel, so I'm not sure how that would work.
Techknight would know best, I think.
c
Techknight would know best, I think.
c
techknight
Well-known member
You would need to change out the CCFL inverter for an EL inverter, and would need supporting circuitry, if not fully custom in order to convert the control signals from the portable, (should be PWM), to the signals needed to run an EL panel.
Basically, an inverter changeover would be the only thing needed here. CCFLs run at 800V to 2KV. EL runs around 90 to 120v roughly 400Hz.
They make these EL panels in various colors including white. but i stuck with light blue, I really wanted aqua. but light blue is good, looks nice
Aqua Green is what is in the emate, I believe.
Basically, an inverter changeover would be the only thing needed here. CCFLs run at 800V to 2KV. EL runs around 90 to 120v roughly 400Hz.
They make these EL panels in various colors including white. but i stuck with light blue, I really wanted aqua. but light blue is good, looks nice
Aqua Green is what is in the emate, I believe.
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techknight
Well-known member
Yup, and at a much lower current than EL.
EL runs at a low voltage, and higher current.
The reason why EL inverters are larger than CCFL, is the frequency. EL frequencies are anywhere from 400hz to 800hz or so. while CCFL runs well above 18khz. maybe even 20 to 30khz.
Easiest EL inverter is taking an old wall transformer, you know, the old 120v to 12v or 9v, and use it in reverse with a 555 timer and switching transistor.
EL runs at a low voltage, and higher current.
The reason why EL inverters are larger than CCFL, is the frequency. EL frequencies are anywhere from 400hz to 800hz or so. while CCFL runs well above 18khz. maybe even 20 to 30khz.
Easiest EL inverter is taking an old wall transformer, you know, the old 120v to 12v or 9v, and use it in reverse with a 555 timer and switching transistor.
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techknight
Well-known member
Probably. But we gotta see if it can deliver the current to the EL without overheating
techknight
Well-known member
Well, The results are bittersweet.
Here is the result after assembly: Looks nice! BUT... and I mean a big BUT...
If you look at the LCD, After its been on for at least 15 minutes, it begins to "develop" the film pull lines as if it were tunnel vision:
These displays are sensitive to this I suppose. I didnt use much heat when pulling the transflective film off, But I did pull hard. I am wondering if I damaged the LCD from doing this, it looks like I did.
Was worth a shot I guess. Next time, I just have to use more heat and pull slowly. be VERY careful. I was pulling on the sheet, HARD.. the tunnel vision "creases" appear to be at the points where I rested after pulling.
Oh well....Its not really affecting it that bad.
there is also a black line that develops on both sides of the LCD as well around the same time. This could have happened before I took the LCD apart ,as I have no idea if this LCD was good or not. I got it for parts, and started with it. This could have been a problem before I even started. I dont know.
Its not affected whether the EL is on or not, it still shows up after awhile. Just like tunnel vision.
Here is the result after assembly: Looks nice! BUT... and I mean a big BUT...
If you look at the LCD, After its been on for at least 15 minutes, it begins to "develop" the film pull lines as if it were tunnel vision:
These displays are sensitive to this I suppose. I didnt use much heat when pulling the transflective film off, But I did pull hard. I am wondering if I damaged the LCD from doing this, it looks like I did.
Was worth a shot I guess. Next time, I just have to use more heat and pull slowly. be VERY careful. I was pulling on the sheet, HARD.. the tunnel vision "creases" appear to be at the points where I rested after pulling.
Oh well....Its not really affecting it that bad.
there is also a black line that develops on both sides of the LCD as well around the same time. This could have happened before I took the LCD apart ,as I have no idea if this LCD was good or not. I got it for parts, and started with it. This could have been a problem before I even started. I dont know.
Its not affected whether the EL is on or not, it still shows up after awhile. Just like tunnel vision.
unity
Well-known member
Not sure what you mean by black lines, but my 170 has some odd black lines/edges. Looks like it was just part of the production process - primitive back then.
As for the creases, you maybe can try massaging to see if they go away. Also did you clean the display back with alcohol or something? My other though may be that its residue.
As for the creases, you maybe can try massaging to see if they go away. Also did you clean the display back with alcohol or something? My other though may be that its residue.
techknight
Well-known member
Nope, screen is clean.
I think the LCD is actually bad. Take a look at this:
That was after about 45 minutes or so? of being on.
Just powered it down, and it seems to have the creases and if you look very carefully, the About Finder "burned in" to the screen.. With the memory etc still present. The LCD panel itself seems to be holding a residual charge which isnt normal.
Thats definitely a bad LCD. Since this is an active matrix LCD, there are little PolySilicon transistors on each pixel. There should also be a ground plane in the panel to dissipate the charge when its not in use, etc, but its not functioning for some reason.
I think the LCD is actually bad. Take a look at this:
That was after about 45 minutes or so? of being on.
Just powered it down, and it seems to have the creases and if you look very carefully, the About Finder "burned in" to the screen.. With the memory etc still present. The LCD panel itself seems to be holding a residual charge which isnt normal.
Thats definitely a bad LCD. Since this is an active matrix LCD, there are little PolySilicon transistors on each pixel. There should also be a ground plane in the panel to dissipate the charge when its not in use, etc, but its not functioning for some reason.
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