E-mu Emulator Sampler User Forum for the EIII EII EI and EIII XP - Emulator II+: new display problem

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Author Topic: Emulator II+: new display problem  (Read 7985 times)
cowboy
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« on: January 23, 2017, 01:51:42 PM »

Hello, I've just upgraded my EII+ with a Lotharek Drive and a new display (MIDAS MC21605A6WD-BNMLW). I've also replaced the IC25 with a SN74LS04N Hex Inverter, but the screen often shows strange character sequences.... Huh  Any ideas? Thanks for your support!!!


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* IMG_2789.JPG (695 KB, 2016x1512 - viewed 622 times.)
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dr.c
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« Reply #1 on: January 23, 2017, 02:15:21 PM »

One first rule is to never, when possible, change a few components at a time.
For example, change the drive first, and see how it works, etc..., otherways you will never know what's wrong !
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Wolfram
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« Reply #2 on: January 23, 2017, 02:34:54 PM »

And check the order of the Display connection.
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Electro disco club
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Sp 12 turbo / Emu II /


« Reply #3 on: January 24, 2017, 12:51:34 AM »

I have thé same issue with LS, SN etc.

I've just replaced thé PSU, wondering if it Will work with a good 5v adress?

I Will check and test with thé midas screen.

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2 hands with 10 fingers
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« Reply #4 on: January 24, 2017, 08:34:36 AM »

Sorry, the midas screen is always mad
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cowboy
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« Reply #5 on: January 24, 2017, 09:11:34 AM »

Thanks for your feedback. Can you recommend a display?
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alka
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« Reply #6 on: January 24, 2017, 06:24:09 PM »

I am using this Midas display with no trouble. Perhaps you have an issue in your Scanner circuit - I've had similar issues with odd characters but it was tracked to a bad IC. I forget which one at the moment... will look when I get a chance.
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HideawayStudio
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« Reply #7 on: May 24, 2017, 01:11:16 AM »

Sorry, the midas screen is always mad

Might be worth trying my usual mod for new displays on EII....  (I'm not saying it will work in your case but its worth a try)

This is actually a common issue which I've reported a fix I came up with before but perhaps not on this site.

The LCD timing on the EII is marginal and although it just about works with older HD44780 compliant LCD modules, many of the modern equivalents have faster timings. 

This often manifests itself by showing nothing, a solid bar or garbled characters on the bottom line of the display.  The top line is always fine with a new display fitted.

The fix I came up with several years ago has helped a number of other owners to make their new displays work so this is definitely worth a try....

FIX: Solder 4.7NF metal film capacitor between pin 1 (Ground) and pin 6 (Module Enable) on the LCD module header.

This works by slightly lengthening the Enable pulse to the display.
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Kalem
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« Reply #8 on: June 02, 2017, 09:35:37 AM »

And check the order of the Display connection.

Yep always check the order first.
« Last Edit: October 15, 2021, 12:41:14 PM by Kalem » Logged
Sandrow
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« Reply #9 on: February 09, 2018, 02:35:02 PM »

Installed same display on board and had the same issue on different menu pages.

Solved with a Ceramic 33pF capacitor between pin 1 and 6.
I'm testing it before soldering properly but at the moment no issues at all.

Cheers.

« Last Edit: February 09, 2018, 02:41:21 PM by Sandrow » Logged
Electro disco club
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« Reply #10 on: April 24, 2018, 09:54:12 AM »

Great,
It works well !

Underground music by night  Shocked

Thanks
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alka
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« Reply #11 on: May 07, 2018, 06:40:17 AM »

Just wanted to update this as I had replaced my display with the MIDAS one as per the instructions here: http://www.nattvard.com/cmi/e-mu-emulator-ii-lcd-screen-change/ and the IC25 change did nothing to correct the timing issue. Unfortunately neither did Dan's solution with the 4.7nf. However seeing that Sandrow had success with the same display with a 33pf capacitor from pin6 to ground i tried a 22pf (closest i had on hand) and it worked! Just thought I'd confirm that this lower value cap solution works across multiple machines.
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dfiorucci
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« Reply #12 on: June 04, 2018, 08:47:23 PM »

Did you remove the other fixes or was this in addition to the other fixes of the resistor and IC25 change?
Thanks,
Dana
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alka
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« Reply #13 on: June 11, 2018, 08:18:50 AM »

just a one-to-one replacement of the display as instructed here: http://www.nattvard.com/cmi/tag/midas-mc21605a6wd-bnmlw/ and one 22pf capacitor between ground and pin 6.
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dfiorucci
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« Reply #14 on: July 21, 2018, 09:49:11 PM »

Just replaced my display with this one.
<http://www.newark.com/midas/mc21605a6wd-bnmlw-v2/display-alphanumeric-16x2-white/dp/03AC3420?CMP=AFF-CJ-6455582-Newark%20Product%20Catalog&source=CJ&CAWELAID=120185550003512238>

Had to change IC25 with a SN74LS04N Hex Inverter and file a small clearance in the circuit board to fit the display in also had to slightly open up the mounting holes.

Looks great
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