Replacing a LCD Display and I need help

[Unkle77]

I have a Roland MC-505 drum machine and i need to replace its failing lcd display and i know absolutely nothing about this area.....

The LCD display (shown below) is a 16 x 2 and has lines missing, I believe this to be due to the lcd display rather than the controller bellow it, is this a fair assumption?

It is back lit but only has 14 connectors to it and as you can see the display is only attached to the controller by a Z-axis strip.

Is it still possible to get the display without he controller as i have looked at farnell and others but i can not find a controller and display that is suitable.

On the display all i have are the numbers DM1268 and IBI M2V0 which when using google dont seem to mean much.

[r221b]

This may be totally unrelated, but since I can't see the pictures, I'll give it a shot. Sometimes these displays are connected to the circuitry with a connector that looks like a piece of rubber. If the connections get dirty, then some or all of the display can go out. If you can sepatate the rubber connector and clean it with alcohol, you might be able to restore the operation Again, since I can't view the pictures for some reason, this is a total guess on my part.

sherlock

[dangus]

If there's 14 connections to the controller, that sounds like it might be the standard HD44780 style LCD controller and interface. So in a pinch another 16x2 display might work, but it may not fit in the case. But there's always duct tape and RTV and ribbon cable, if you don't mind how it looks.

But, first try r221b's suggestion: I've run into several different displays where the problem was just the interconnection between the LCD display proper and the controller board. Sometimes flipping the zebra strip end for end worked, or wiping the contacts clean with a Q-tip moistened with isopropanol.

A google search revealed that other people have had problems with the displays. Dealer cost on the display is said to be about $60.

[anatech]

Hi Unkle77,
I recognize that type of assembly. It's trouble and the connecting flex is the problem. You can not easily fix these, plus they are delicate. I believe it is sold as one assembly due to the way it's connected together.

If you are lucky, you may be able to replace the cable with an LCD socket and ribbon cable (soldering that to the PCB).

-Chris

[jleaman]

are you able to post pictures of what this failing display looks like ? have you tried to talk to the manufacture and see if they will sell you the lcd module ?

[gmphadte]

The ribbon cable is pasted to the display and make connections by pessure AFAIK. Some connections give up over time due to loss of pressure. Try applying pressure on the cable. If the display shows the missing lines, then u know how to fix it.

Gajanan Phadte

[Unkle77]

a few quick questions:

so if hook up a new lcd, but i do it wrong as i don't have the schematic of the MC-505 is there a chance i will fry something??


also i will try to phone roland but i dont think they sell the lcd, they only replace it so id have to send it off. but i dont really want to do this as i have already done some diy on it.

i have pressed down on the flex cable but nothing has improved. i'll play around with it a bit more i think.

[Unkle77]

Here is what the lcd looks like when it is on.





as you can see most are missing

[Unkle77]

Its £52 to get the LCD from Roland, which is almost as much as i paid for the whole drum machine!!

So the question is, if i by one of the recomended LCD displays above how should i go about connecting it and also if i get it wrong is there a chance of me breaking the entire drum machine??

ie frying some circuits or will it only be the LCD that would die?

[Elijah]

Just a clarification - when you 'played' with the connector, did you try running a suitably small/rounded object (maybe a smoothe/rounded pen cap) along the actual point of contact between the printed ribbon and the mating surface of the LCD?

Just curious if it might allow a few more dot's to properly display - at least momentarily while you gently press the individual contacts? That would help isolate the problem to that particular area... Possibly allow the use of some sort of clamp?

thanks, Elie