Re: IIc Flat Panel Display

[Michael J. Mahon <mjmahon@aol.com>]

<giorgio.morocutti@alice.it> wrote:
> Il Sat, 02 Jun 2012 16:29:17 -0500, Michael J. Mahon <mjmahon@aol.com>
> ha scritto:
> 
>> <giorgio.morocutti@alice.it> wrote:
>>> Il Sat, 02 Jun 2012 12:45:47 -0500, Michael J. Mahon <mjmahon@aol.com>
>>> ha scritto:
>>> 
>>>> Wayne Stewart <waynejstewart@gmail.com> wrote:
>>>>> I have a couple. The only place where they're really easily readable
>>>>> is outside in sunlight
>>>> 
>>>> Has anyone ever opened one up and played with the LCD bias?
>>>> 
>>> And there are some schematics?
>>> 
>>> Thanks
>>> 
>>> Giorgio
>>> 
>>> 
>>> Apple II and Apple III forever !!!
>> 
>> It should be quite easy even without schematics. 
>> 
>> But after posting, I realized that a panel of this vintage probably has a
>> bias adjustment, labelled "contrast" or something similar. If this control
>> can change the display from "off" to "black", then that's all that bias can
>> do. If it is all the way at one end for best display, then changing the
>> bias range could make a real improvement. 
>> 
> Sorry, no trimmer or potentiometer on inside printed circuit.
> The external contrast knob is already at maximum.
> 
> Thanks for your suggestion
> 
> Giorgio
> 
> Apple II and Apple III forever !!!

If it's at maximum and the display is still improving when it hits the
stop, then it's a good candidate for a modification to improve the range of
adjustment. 

This could be as easy as reducing the value of a resistor connected to the
pot or as hard as providing a DC voltage source a couple if volts higher
than the current voltage. 

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon