Sign in to follow this  
Followers 0
fussylizard

40x2 Green-on-Black Optrex Displays - ORDERING INSTRUCTIONS

74 posts in this topic

@fussylizard: yes, great packing, now I have enough bubble wrap for a batch of sammichSID kits ;)

Glad I could help. :-)

It was also nice to get rid of a bunch of bubble wrap I'd accumulated over the years and held onto in case I needed it for something.  I bought fresh bubble wrap for individual LCD packing, but used the "recycled" bubble wrap to fill out each box of displays.

Share this post


Link to post
Share on other sites

Optrex provides the datasheets, pinouts, drawings, etc. via their web site, but you have to sign up and they email it to you.  There's nothing special to it (uses a standard pinout), but I posted a PNG of the drawing and pinout at the start of this thread (http://www.midibox.org/forum/index.php/topic,14045.msg120798.html#msg120798) in case you want it without hassling with the Optrex site.

Share this post


Link to post
Share on other sites

Received mine today. Thanks!!!

Share this post


Link to post
Share on other sites

same, received this morning.

Smoothie!

thanks, Chris.

Share this post


Link to post
Share on other sites

@vcfool, kartoshka - thanks for letting me know!  I like checking names off my list.

If anyone else has received their LCDs yet but has not posted here or sent me an email/PM, please do so.  I'm holding a few LCDs in reserve in case someone's package gets lost but once everyone has theirs I can make those available to others that might be interested in them.

Thx,

C

Share this post


Link to post
Share on other sites

Got my lcd's today, thank you very much!!!

Share this post


Link to post
Share on other sites

items received : thanks :)

super well packed !!!

Share this post


Link to post
Share on other sites

@mirmidi, julianvoirin - great, thanks!

Share this post


Link to post
Share on other sites

yay!! today they showed up!

thank you very much, very good packing!

:D

Share this post


Link to post
Share on other sites

@rosch - Great!  Sorry that it took so long in transit.  BTW Thx again for the PCB+chips!

Is anyone else from the initial batch of orders still waiting for their LCDs to arrive?

Share this post


Link to post
Share on other sites

Wilba's got mine, but that's something I'll have to nag him about  ;)

Where's my eucalyptus stick when I need it?

Oh there it is

*whack*

Share this post


Link to post
Share on other sites

I bitter git on wuth ut eh bro?

Share this post


Link to post
Share on other sites

Retrieved mine from the customs few days earlier.

Thank you very much! :)

Share this post


Link to post
Share on other sites

All,

Nsunier and I were discussing offline the background brightness of the Optrex LCDs. The LCD I'm using on my MB-FM has an only slightly brighter background than the yellow-on-black CrystalFontz LCD I have on my MB-6582 (which I'm very happy with), so I was fairly happy with background brightness on the Optrex display using a regular core module.

However, Nsunier was wanting a dimmer background so for fun I did some hacking about today on my core board (R4d from SmashTV). The LCD backlight brightness is controlled by the resistance through the 10k trimpot P1 and 1k resistor R4. These affect how much current the backlight gets through transistor T1. So with the default parts you basically can vary from 1k to 11k in resistance. (Those with more electronics knowledge than me, feel free to jump in with corrections!)

After experimenting with a 500k trimpot I found my preferred brightness around 35k - 40k total resistance with the LCD I have. I had to adjust contrast trimpot P2 slightly but I got a fairly dark background with minimal dimming of the characters. Greater resistances seemed to dim the characters at about the same rate as the background so no further gains in display quality were forthcoming.

I plan on changing out P1 on my core board with a 50k trimpot (Mouser part number 531-PT6KV-50K). I'll probably leave R4 as-is (the bulk of the resistance will be coming from the trimpot), though other values could be used of course. A 100k trimpot could also be used, especially if you want an even darker background.

Overall I think you will be fine with the "default" 10K trimpot as specified in the design (and supplied by SmashTV for example), but for those wanting near perfection, I recommend using a 50K trimpot for P1.

Happy November!

Regards,

Chris

Edited by fussylizard

Share this post


Link to post
Share on other sites

for the record, if you already soldered the lcd pots and don't want to mess with the pcb, you can add a resistor between led+ wire/ pin 15 on the lcd, lcd on my mb6582 worked fine with an 8k res(low mA led lcd)

4069121116_1f662c3094.jpgbigger image here

you could try with a 50k potentiometer to get a proper value, then just replace the pot with a resistor thumbsup.png

Share this post


Link to post
Share on other sites

I've got one of these:

productLarge_9724.jpg

Very handy!

Hey, that's pretty handy. I just used a dual-gang 500k linear pot. One, er, "gang" was the resistance in the circuit via minigrabber clips and the other gang was hooked up to my multimeter. But having resistance pre-printed is rather nice...

Share this post


Link to post
Share on other sites

for the record, if you already soldered the lcd pots and don't want to mess with the pcb, you can add a resistor between led+ wire/ pin 15 on the lcd, lcd on my mb6582 worked fine with an 8k res(low mA led lcd)

4069121116_1f662c3094.jpgbigger image here

you could try with a 50k potentiometer to get a proper value, then just replace the pot with a resistor thumbsup.png

Doesn't this approach (soldering between LED+ and the wire) drop the backlight voltage? By changing resistance at P1 or R4 (per my recommendation) you are changing how much current flows through T1. I need to break out my electronics book to sort this out for sure (I'm sure there's an Ohm's law problem in here somewhere!) but I guess if this approach works also it is nice to have options. Might have to give this a try just to see if I can get even better results out of the display...thanks for the input!

Share this post


Link to post
Share on other sites

Doesn't this approach (soldering between LED+ and the wire) drop the backlight voltage? By changing resistance at P1 or R4 (per my recommendation) you are changing how much current flows through T1. I need to break out my electronics book to sort this out for sure (I'm sure there's an Ohm's law problem in here somewhere!) but I guess if this approach works also it is nice to have options. Might have to give this a try just to see if I can get even better results out of the display...thanks for the input!

ah, probably you are right(electronics newbie here), I just measured the backlight voltage after the resistor to be sure it was between this particular lcd specs... after burning a $30 lcd because I didn't read the datasheet and connected that lcd without any mods :)

of course I got the intended effect of a darker backlight after all.

let us know what you find out on your tests please ;)

Edited by sineSurfer

Share this post


Link to post
Share on other sites

Doesn't this approach (soldering between LED+ and the wire) drop the backlight voltage? By changing resistance at P1 or R4 (per my recommendation) you are changing how much current flows through T1. I need to break out my electronics book to sort this out for sure (I'm sure there's an Ohm's law problem in here somewhere!) but I guess if this approach works also it is nice to have options. Might have to give this a try just to see if I can get even better results out of the display...thanks for the input!

All resistors in the signal path add up since thay are connected in series. They will all have the effect of limeting the current flowing throw the cirquit. If the voltage at the LCD inlet is affected depends on what more resitance there is in the other parts of the signal path. It has the same effect to 1) change R4, 2) change the trimpot and 3) add additional resistors.

Thanks for the tip! I will change my resistor to make the LCDs even nicer!

Share this post


Link to post
Share on other sites

Hi Chris

I got my 4 Displays yesterday.

Thanks again for your effort

Regards

Jo

Share this post


Link to post
Share on other sites

Got my displays.

Thanks for this bulk order!

Share this post


Link to post
Share on other sites

Thanks to everyone who participated in the bulk order, you were great to work with. This bulk order is now closed. (Big sigh of relief!)

If anyone is interested in more of these displays, please post to this thread or send me an email. If there is enough additional interest I will consider doing another carton (80 pieces) assuming Optrex still has them on sale.

Hope everyone enjoys that green LCD goodness! Definitely look at the tweaks I posted earlier to get the most out of these great displays.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0