Service Manual / Repair instructions wanted

[selco]

Hallo all,
I still try to awake my C=A4000T again after a sudden, silent and unmotivated death. (Died without any reason while running)

So I am currently looking for repair instructions or a Service manual. I hope to find there instructions to locate the problem (wich signal should be measurable on wich pin, if not what to test then...)

Does anybody have such literature (in electronical form if possible) or can point me to a good link?

Best regards selco

[TNovosel]

Try this link...
Great amiga hardware site!!!!
http://amiga.serveftp.net/

[ZyBeR]

Now my A4000T have died as well.

Did you find ther error on yours?
How shall I proceed with error checking?

[X-ray]

Selco and Zyber

You should both post your configurations here. Maybe it is something that can be fixed by yourself. There have been quite a few 'dead' A4000Ts that have been fixed by the user, no repair necessary.
Also, when you say that the machine is dead, what do you mean? Is there no power when you switch on, is there just a black screen, is there any colour displayed at all?

[selco]

Hi X-ray,
I posted a detailed description of my problems in another thread:

http://www.amiga.org/forums/showthread.php?t=16667

There I also wrote what I could check so far.

Voltages are OK, all clocks that I could find are OK, the screen remains black, The Power-LED does -NOT- flash after power ON, The Early Startup menu cannot be accessed. The computer does -NOT- try to access a floppy disk.

This all happed without any reason.

All cards and harddisks have been removed, nothing changed.

Power connectors to the mainboard are ok. I exchanged the power supply but also no change.

So I ask for instructions how to locate the problem.

BTW: I had a Cyberstorm 060/50 in the system when it died. I replaced the Cyberstorm by the original CPU board of the C=A4000T (and checked for the correct jumper settings on the mainboard) but nothing changed!

So I assume the problem is on the motherboard.

I checked the ROMs and they are OK and sit perfectly in their sockets. (I read-out the ROM-images and checked their checksum manually)

As I said: I did nothing that could be reason for the problem. The Amiga was running in that configuration for ages about 16 hours per day (as apache server). It was running when it suddenly crashed (and never came up again) without beeing tuched! And there was no lightning then, neither...

So any instructions what clocks/voltages/signales I could check to locate the problem would be very welcome!

[X-ray]

@ Selco

Those are the same symptoms I had when my A4000T died because of a dead CIA chip. When you turn the machine on and place your fingertips on the CIA chips, does one of them get warmer than the other one?

Edit: also...when you test the system with minimum components (no HD and no cards, other processor board with correct clock jumper settings) you MUST connect the floppy drive. And you should perhaps try a different SIMM or two on the mobo.