My EIII won´t boot/blank screen

[recoil]

Hi!

i just bought a non working EIII keyboard. And would like to make it run. This is what i´ve done until now:

1. PSU seems to be fine. Adjust it to 5.05v. (as the forum describes)
2. A dead non working HD was replaced for a working one.
3. Changed the places of the ram simms. (as the forum describes)
4. Just left the cpu board and memory board for test purpouse.

Turn it on!

Blank screen
2 leds of the panels are on but no buttons responding
no led on the 3.5 diskdrive either.

HELP!!!!

[dvdborn]

I once had a blank screen after opening my EIII. It freaked me out and checked all the cables with no joy.

In the end it was just the contrast button that got turned so that the screen became blank. Turning it back to its proper position revealed the characters again on the screen.

Though, when you have no buttons responding on the panel it'll probably not help just turning the contrast button.

[recoil]

Thanks for your reply.

Tried the contrast pot with no luck. Seems like the "scanning" in the cpu board is not working properly. If so, i´m fried!!.
After turn it on, without the os loaded (since i don´t have it yet), should the buttons work?.

regards.

[Zomnius]

I think it needs or the hard drive / or a floppy with system on it?

maybe a scsi zip could help?

who knows more?

[mg73]

Did you solve this?
have the same problem on one of my mine.

and it´s not the hardrive or floppy.

[mg73]

what happened to mine was.
I had one working CPU board and one that could  only boot from floppy
it just kept scanning scsi id´s when trying to boot it from the hardrive.

Began to swap IC between the working and not working
one by one with no result.
First the obvious scsi controller IC etc
then I just changed all at once(yes i know you shouln´t!)
Now both of board just are blank!!
Just the the two rows of squares.

Anyone have any idea where to start, any of the IC`s extra sensitive for pulling from socket??
I have a third working unit but don´t wanna mess up that one also
by pulling IC´s from that CPU board.
But I tried both of the non working board in it just to see that there were nothing
else that was faulty but they didn´t work there either.

[Zomnius]

somebody?

thsi seems to be happening to a lot of EIII's.

I also have 2 EIII with screens with black cubes on it...

where to start?

[dvdborn]

I'd say start by calibrating the power supply.

[dr.c]

First thing : connect t another HD on top of the old wich you have disconnecetd, momentarily, and see if your emu starts, al least with a display.
Don't care what kind of date or whatsoever, just a SCSI disk, ok ?

If display appears, it means the disk was dead. To be changed.

The second thing is a chip near the flat cables on the CPU board (the second from top) wich dies. Its, if I remenber well, IC40 and should be a 74HCT244, it has a retrofit under (modification). In case of doubt, send me a picture somewhere.
If this is it, change it carefully by a 74LS244 (that is okay !) mounted on an excellent quality socket.