New OLED Install: Gibberish Displayed

[who]

I found an OLED display that matches the original dimensions closely enough that no modifications were necessary to mount it.  The problem is it either displays nothing, or displays lines, dots and blocks as shown in the attached screenshots.  I checked the pinouts between the previously installed Optrex DMC-16207 and the new OLED and they appear to match:

New:

http://www.vishay.com/docs/37704/oled016n002e.pdf

OLD:

http://www.infidigm.net/projects/dtmf/16207cae.pdf

The hex inverter installed is a Texas Instruments SN74LS04N.

one two or three occasions, the first letter of both lines appeared correctly and would change as I pressed the page buttons.  (i.e. Preset Definition, Voice Definition, etc.)

Any ideas?

[alka]

Hideaway studios had a fix for this that's been helpful in most cases: http://eiiiforum.com/index.php?topic=2965.0

[who]

Thanks for your help Alka!  I had seen Hideaway Studio's post, but since he said the first line is always correct, I didn't think it applied.  Do you know otherwise?  Have you installed an OLED and had the same problem?

[who]

Hideway Studio doesn't mention much about the capacitor spec and there are numerous choices on Digikey.  How does this one look?

https://www.digikey.com/product-detail/en/panasonic-electronic-components/ECQ-E1475JF/P14624-ND/2567775

[alka]

Oh sorry not sure.. I had a similar issue after a new display was put in - can't recall what line as affected though.. hideaway's solution whereas helped many others did not help me. I have to keep an oscilloscope probe hooked to the pin of the display!!

In any case the cap you selected is too large - maybe one rated 16v-25v should be ok... not the 100v

[who]

I've made some progress:  I went back and checked my soldering and found pin 1 was not connected.  (Uggh!)  Now I consistently see the first character of line 1 and line 2.  Additionally, when I run the scanner disk I can confirm all buttons, sliders, keys and velocity work.   (see attached image)

My next thought is to try a different hex inverter, but I have no clue what I'm doing.  If anyone has a suggestion, I would appreciate it.

[who]

Oh, one more thing:  I tried Hideaway Studio's suggestion and unfortunately, it didn't help.

[lunatic]

Ok, so I have found the part numbers. I had some gibberish on my display at first too. Actually though changing the hex inverter to the Texas Instruments type you have installed did the trick. The one that was installed in my EII before was also a TI one, this: CD74HCT04E.

Have you checked the conductivity of your solder work?

[who]

Hi Lunatic,

Thanks for your response!  Which display make and model did you use?  I checked my soldering and I think it is good.

[Sandrow]

Hi all there.

I'm into a restoration of an Emulator II.

I've placed an OLED Gotek Floppy emulator, and i thought that a blue WINSTAR OLED on main display could be great.

Actually it is, pity that only the first "Column" of characters are correct, the other character slots are garbled.

So far:
- i've tried to Slow down pulse with 4n7 and several other different values capacitors between ground Pin 1 and Enable pin 6 but nope, it changes nothing.
- I've replaced the horrible flat cable with strip line ribbon cable in order to avoid further desoldering/soldering reworks on main PCB and display.
- Tried to place SN74LS04N , SN74HC04B, in Hex inverter chip 25 But nope again.

Meanwhile i've picked up an horrible standard LCD display in order to keep the machine giong on, but i'm very sad since the Oled looks waaaay better.


WINSTAR OLED:
http://www.winstar.com.tw/uploads/files/fd183ee5ec738b8c2201c3a151b44ed1.pdf

Original E-mu Display:
http://www.infidigm.net/projects/dtmf/16207cae.pdf

Any idea?