Alesis D4 Display replacement(?)

[Mraverty]

Hey all

My D4 screen has started to go south on me. It's still readable (for now), but about 1/4 of the display has been replaced by black squares.

Anybody savvy with this sort of situation? I believe it is some type of backlit LED screen.

I'm not afraid to crack 'er open and do a little soldering, but a techo-whiz I am not, so I would like to avoid any complex circuit board corrections. Thanks for the help in advance!

[jrcel]

Possibly here;

http://www.mpja.com/

http://www.futurlec.com/LCDDisp.shtml

http://www.junun.org/MarkIII/Info.jsp?item=35

http://www.google.com/products?sourceid=navclient&ie=UTF-8&q=16x2+lcd+display&um=1&sa=X&oi=product_result_group&resnum=1&ct=title

[delude]

You could use the form on the Alesis website to contact them and ask specifically what type of LCD screen is in the D4, so you could replace it smoothly.

http://alesis.com/contact/index.php

[stevewahl]

My D4 LCD replacement experience.

I just replaced my D4's LCD last week. I was not very satisfied with what I
could learn about doing this with a google search. So, I wrote this up!

Alesis D4 LCD Module replacement

The backlight went out long ago on my Alesis D4, and since putting
together an edrum kit, I wanted it working again. Replacing just the
backlight might be possible, but replacing the module is what I went with.

Part: The original LCD module was a DataVision, with a P19-141 marking
on it, and CSI-024C on the backlight. I could not find one of these,
nor much info about it on the web.

I used a Lumex LCM-S01602DSF/C. Available from DigiKey and Mouser,
and others I'm sure. It has a green LED backlight, different from the
original D4. The circuit board was the same width, but not quite as
high as the original.

HINT: at the same time, order some header pins to connect the ribbon
cable to if you don't have some on hand. The LCD module comes with
empty holes.

What you need to know:

1. Because the ribbon cable connector is soldered to the back of the
LCD module, its pins are swapped. The pins on the motherboard are
swapped to match this. This should not affect you if you solder
header pins to the new module in the same way. But if you take some
other aproach (see below), beware that in the ribbon cable, the red
stripe conductor is pin 2, followed by 1, 4, 3, 6, 5, and so on.

2. Some information on the web talks about swapped power and ground
pins. I don't know how that relates to the pins being swapped in the
cable; I *think* if you just solder in header pins, you don't need to
reverse the power pins. But I don't guarantee that, so, after you
hook up your brand new LCD module, use a meter to check for certain
that the ground pin on the module is connected to some other ground on
the motherboard -- BEFORE you apply power!

3. Pin 3, LCD Drive voltage, was a negative voltage on the old module,
which is incorrect in the new module. But you must connect pin 3 to
something, leaving it unconnected yields only a blank display.

4. At least in the version of the module I got, there are pads for a
surface mount resistor and a solder bridge to connect the backlight to
the main +5V supply for the LCD module. And this is how the original
module supplied power to the backlight as well; I believe the resistor
was 20 ohms.

Discussion...

If you have the pins for the header, it should work to do this: Solder
pins out the back of the module (just as the original did), except
leave out pin 3 so the ribbon cable doesn't connect there. Instead,
connect a resistor from pin 3 to ground (I don't have a specific value
for you, sorry; I just grabbed one at random and it worked). Put a
resistor across the pads for backlight power, and solder bridge the
other pads. Connect it with the power off and make absolutely certain
that ground on the LCD is the same as ground on the motherboard.
Cross your fingers and power up.

I did not have header pins handy, but I did have a ribbon cable that I
soldered directly to the LCD. I don't particularly recommend this
approach. I probably wasted an hour in frustration because I didn't
notice the reversed pins issue at first!

Once I got the LCD itself working, I stole whatever backlight power
resistor was on the original module to put on the new one.

The swapped pins really threw me for a loop. Hopefully this will help
the next guy avoid such confusion!

--> Steve Wahl