Front panel LED died

[dvdborn]

The blinking red sampe LED  on my EIII stopped working.

Has anyone ever replaced and sourced one of these?

[ARES]

the led of my "sample" button doesn't work too...

So ... HEEEEELP 

[dr.c]

Just buy a f... led and replace it !


Its not a self blinking model

[midipuppies]

Hey DVD, I had a similar problem with my keyboard. It was the master module led. Turns out that the ribbon cable that goes to the front panel (the large 60 contact one) had a bad wire. Most of my internal ribbon cables had to be replaced for this reason. Also, check where that cable connects to the front panel. It is not your average connector. Make sure that the clip is fastened down tightly as on the other side of it there are just bare pins that poke through EACH of the 60 different wires. I had to manually push them on and puncture the cable in the the right spot to get it right. It took at least 4 tries. Sometimes the display was garbled, sometimes LEDs were out etc. Just a thought as LEDS rarely burn out.

Jay

[dr.c]

I had once an LED wich KILLED the power supply. I could not believe it !
The traces, neither the flat cable didn't suffer. I really wonder HOW this could be possible because the LEDs are most of the time remoted by a buffer and logicaly, the buffer circuit would have blown away before ! Nope...

This is one of the mysteries I had to deal with Emu repairs.

You are right that LED break very rarely, I think I have seen this three times in 25 years of repair, minimum 5 machines a day.

[dr.c]

Why not at first, a front panel test, uh ?

Master 8 0 1358 1

[dvdborn]

I had some time today to look for the not working LED problem.

The good news was that all LED's on the front panel are in sockets.
I noticed that they all had black legs due to corrosion. So I started by cleaning the legs of all the LEDs with some fine sandpaper. I also applied a bit of contact cleaner to the sockets.

I then swapped the non working sample LED with a working one. But without any success. The sample LED still refuses to light up when the sample mode is selected. So the LED in itself isn't broken.

I then tried to fasten the flatcable connector that goed to the front penal. Again no luck.

So if anyone else has some ideas I'll be glad to hear them.

David

[dr.c]

Its a nightmare...

Look at the attached docs :

I looked for an hour on the manual, found the page with the sample led (p114 CN5-1) why TWO leds are drawn, its a mystery.

Now, if I look at p124, CN5-1 is going to the ground.

This means that the LED is between +5V (page 114, and ground (p124)

Pfff....

[dr.c]

the following page

[dvdborn]

Hi Dr. C,

Thanks for the search in the Service Manual.
My next step would be to check the flat cable that runs to the front panel.

Concerning the 2 LEDs on the schematics: When you look at the LED you'll see that it has 4 legs. So I'm guessing the LED housing contains 2 different LEDs.

[dr.c]

Try as well to fill the metallized holes, I had problems with them by times

[who]

I'm working through a very similar problem, except mine is the Preset Management LED.  I was successfully able to jumper the LED so that when the Master button is pushed, the Preset Management light works, so I know it's not the LED.  Anyone have any suggestions?

[dvdborn]

In my case it was fixed by replacing the ribbon cable between the panel and the CPU card.