Emu XL-7 & MP-7 User's Group

• 24x2
• 118mmX36mmX10mm
• 14 pin

Someone on EBay is selling a used display for $40 you can mess with....auction number 290460335559.

Bob
El Segundo, CA


  ----- Original Message ----- 
  From: Bob S. 
  To: xl7@yahoogroups.com 
  Sent: Monday, August 23, 2010 18:21
  Subject: Re: [xl7] modding LCD ?


    
  You know, they say, if it ain't broke....don't try to fix it !!

  Why not use another approach....change the color of the backlight only!

  I believe the backlight on the command station is LED, so with a little careful surgery, you might be able to replace the LED chips with blue ones.....and if you screw it up, there is always a new display from EPR....

  Bob
  EL Segundo, CA

  -----Original Message-----

  From: James Ulibarri 

  Sent: Aug 23, 2010 5:47 PM

  To: xl7@yahoogroups.com

  Subject: [xl7] modding LCD ? [1 Attachment]

  [Attachment(s) from James Ulibarri included below]


  Ok, I have done a lot of research on this. I was going to keep it on the down low and then just kinda bring it to the forum when it was done, but I having a problem sourcing parts. 
  Has anyone successfully swapped the Command Station LCD?

  Here is what I know so far:

  The original unit is:

  24x2118mmX36mmX10mm14 pin
  I want a BLUE unit to go with my PX-7. But it's impossible to find a unit that is 14 pin. I talked to Chrsystal Fontz today and their tech said you probably could use this one, 

  At this point this won't work. 

  http://cpc.farnell.com/1/1/26079-lcd-module-alphanumeric-24x2-mc24021a9-sblw-everbouquet.html

  http://www.crystalfontz.com/product/CFAH2402ATMIJT.html

  The Farnell unit's connectors are in the wrong place. The factory connector would have to be scrapped and wired appropriately. Anyone have schematics and feeling ballsy? The Crystal Fontz unit is

  16 pin and their tech's said we might end up loosing contrast control. Crap. I don't want that. I've checked Ebay also and there are some good deals but nothing for this application really. 

  EPR sells the factory replacement for $79.80, and mine works fine. I have no use for that. I want a blue backlit unit. I checked out the Nortitake vacuum tube units also. No dice. 

  I have attached a picture of the original. 

  Anyone have any information on this mod? Has anyone else got anything else out there to work?

On Mon, 23 Aug 2010, James Ulibarri wrote:

> I want a BLUE unit to go with my PX-7.  But it's impossible to find a 
> unit that is 14 pin.  I talked to Chrsystal Fontz today and their tech 
> said you probably could use this one, At this point this won't work.
==================

i've done a fair bit of backlight modding, and if it was me, i'd try to 
find a "drop in" replacement of any color, then just swap the LED(s). but 
i'd do it on the spare, or at least have a spare on standby.

personally, i find green LED backlit LCD much easier on the eye's than 
blue LED. the K5000 is a nice blue, but that's EL, not LED.


-- 
         ...atom

  ________________________
  http://atom.smasher.org/
  762A 3B98 A3C3 96C9 C6B7 582A B88D 52E4 D9F5 7808
  -------------------------------------------------

 	"How often, or on what system, the Thought Police plugged in
 	 any individual wire was guesswork. It was even conceivable
 	 that they watched everybody all the time. But at any rate,
 	 they could plug in your wire whenever they wanted to."
 		-- George Orwell, "1984"

Swapping LEDs is probably not going to work. Different LED colours have 
different forward voltage drops and blue LEDs tend to require a larger forward 
voltage drop than most. A typical LED has a forward voltage drop of around 1.2 - 
1.8 volts, whereas blue LEDs often have forward voltage drops of 2.5 to 3.1 
volts. If you merely replace the LEDs you probably won't get enough current to 
get any useful backlighting. Also blue LEDs often require a higher current to 
generate the same luminosity as other LEDs.

Probably [I haven't checked] the backlight input requires 5Volt (or possibly 
3.3Volts) and in that case there will be a current limiting resistor which will 
be too large a value. You would need to find and replace the resistor(s) with 
smaller value ones. Alternatively, some LCDs just provide access to the anode 
and cathode of the LEDs for backlighting and you need to provide some surrent 
limiting of your own. In this case you will need to find that circuit (perhaps 
only a resistor) and modify it appropriately.







________________________________
From: Atom Smasher <atom@...>
To: xl7@yahoogroups.com
Sent: Wed, August 25, 2010 10:00:30 PM
Subject: Re: [xl7] modding LCD ?

  
On Mon, 23 Aug 2010, James Ulibarri wrote:

> I want a BLUE unit to go with my PX-7.  But it's impossible to find a 
> unit that is 14 pin.  I talked to Chrsystal Fontz today and their tech 
> said you probably could use this one, At this point this won't work.
==================

i've done a fair bit of backlight modding, and if it was me, i'd try to 
find a "drop in" replacement of any color, then just swap the LED(s). but 
i'd do it on the spare, or at least have a spare on standby.

personally, i find green LED backlit LCD much easier on the eye's than 
blue LED. the K5000 is a nice blue, but that's EL, not LED.

-- 
...atom

EPR Electronics sells a blue LCD especially for the command station, about $79 !

http://www.eprelectronics.com/store/html/Products/E-mu-Accessories/MISC/index.html

They are E-mu's parts supplier...

Bob
El Segundo, CA


-----Original Message----- 
From: James Ulibarri 
Sent: Aug 27, 2010 7:01 PM 
To: xl7@yahoogroups.com 
Subject: Re: [xl7] modding LCD ? 

  



The part arrived today.  I will drop off my PX-7 to the tech in OC and let you guys know how it goes in about a week. 
The Crystal Fontz unit seems really solid and built like a little brick over the stock unit (Nippon Electric Glass Inc).   I will be so stoked if it works.






On Wed, Aug 25, 2010 at 4:15 PM, James Ulibarri <jamesulibarri@...> wrote:

I ordered the blue LCD from Chrystal Fontz and it will be here next week.  I have a tech in Orange County that is really good.  I am not gonna mess with it.
If it was plug and play then fine, I could do it.  But he has to create a work around I think for a couple of the pins, or lack there of (I don't remember).  He already knows of a couple solutions.  My biggest concern is losing contrast control.   I'll only be out like $30 plus labor if it doesn't work out.  Not a big deal. 
I'll let you know what happens soon. 







On Wed, Aug 25, 2010 at 4:08 PM, Jack Pratt <woodsworth1@...> wrote:


  




Swapping LEDs is probably not going to work. Different LED colours have different forward voltage drops and blue LEDs tend to require a larger forward voltage drop than most. A typical LED has a forward voltage drop of around 1.2 - 1.8 volts, whereas blue LEDs often have forward voltage drops of 2.5 to 3.1 volts. If you merely replace the LEDs you probably won't get enough current to get any useful backlighting. Also blue LEDs often require a higher current to generate the same luminosity as other LEDs.

Probably [I haven't checked] the backlight input requires 5Volt (or possibly 3.3Volts) and in that case there will be a current limiting resistor which will be too large a value. You would need to find and replace the resistor(s) with smaller value ones. Alternatively, some LCDs just provide access to the anode and cathode of the LEDs for backlighting and you need to provide some surrent limiting of your own. In this case you will need to find that circuit (perhaps only a resistor) and modify it appropriately.









From: Atom Smasher <atom@...>
To: xl7@yahoogroups.com
Sent: Wed, August 25, 2010 10:00:30 PM

Subject: Re: [xl7] modding LCD ?

  

On Mon, 23 Aug 2010, James Ulibarri wrote:


> I want a BLUE unit to go with my PX-7. But it's impossible to find a 
> unit that is 14 pin. I talked to Chrsystal Fontz today and their tech 
> said you probably could use this one, At this point this won't work.
==================

i've done a fair bit of backlight modding, and if it was me, i'd try to 
find a "drop in" replacement of any color, then just swap the LED(s). but 
i'd do it on the spare, or at least have a spare on standby.

personally, i find green LED backlit LCD much easier on the eye's than 
blue LED. the K5000 is a nice blue, but that's EL, not LED.

-- 
...atom