TI-H: EL Backlight installed!

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TI-H: EL Backlight installed!


Greetings all!

I got the supplies for the first 7 EL backlight kits on Friday.
I spent a couple hours installing my kit, and found that
it works just fine, looks great.  There is a minor bug with
the display dimming when the inverter is running, but turning 
up the contrast a few notches makes it easily visible.  

I'm not sure what is causing this.  I thought it might be the 
inverting causing some AC noise in the power supply that could 
effect the power for the LCD, but a bypass cap on the inverter
power pins had no effected.  I thought perhaps the inverter
was pulling more current than my old battries were capable
of supplying, but an unregulated 6vdc wall supply did not
have any effect on the problem either.  I ran the inverter
and backlight off the calculator, but not installed, so
proximity to the LCD does not seem to be a factor either.
The inverter and lamp draw 38ma.
If you have any suggestions about this, please let me know.

I currently have the inverter powered directly off the battery
using a switch to power it.  However, I dislike having to 
switch the inverter off with the calculator, so I am going
to add a transistor (and base resistor) to switch the lamp
off with the calculator.  This way the lamp can be switched
on or off when the calc is running, but is always off when
the calc is off.

The inverter is larger than my supplier said it would be,
but it still fits in the TI-85, right beside the battery
case, on the left side of the calc (as viewed from the
back).

I will be providing detailed instructions on how to install
the backlight, along with pictures of my installation.  I'll
put these up on a website somewhere, in addition to mailing
them to those who order.

To those who have already sent me money for the kits, I have
to pick up some more heatshrink, but I should be sending out
the kits in about two days.

To those of you who are officially on my order list, but I
have not received payment from, I'll order and prepair your
kits as soon as I get your payment.

I'm posting this to the list in addition to the people who
ordered incase anyone else wants to start a new list.  There
are already one or two people who have expressed an intrest
in ordering, but I will need 6 or 7 people before I can order.

Thats all I can think of for now, let me know if you have
any questions about the kits or installation.

David Knaack,
With a turboed and EL backlit TI-85 :)
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