How to fix and AmigaOne G3

I post the same info. now as on amigaworld.net:

Hi, I'm in the same business trying to diagnose my dead AmigaOne SE. The motherboard powers up, MB-led lights up, ethernet and keyboard-leds blink once at power on, but no picture on screen. Serialport gives no ouput, if I have done it right.
Only chip that feels warm is the Articia S, but CPU is under fan so hard to check.


I've tried so far:

- disconnecting everything

- tested that the PSU works stable with another machine

- tested changing ram slot

- new battery installed

- testing without graphics

- connecting usb2serial cable from PC


Questions:

- I'm testing with 9600 and 115200, 8N1, no flow, correct?

- I'm also using a usb2serial cable, which had male plug, so I had to solder on a female plug instead, this shouldn't mean anything? But then I hear something about null-modem cable, do I have to cross two leads on the standard usb2serial thing to make it a correct cable?

- Could it be that Uboot is blank after motherboard has been without power for long? What do I do in that case? Haven't used the board in ages, and it had the problem then already.

- If I can't get serial working, or don't get an output, is there another way of checking the CPU? Is the fan glued on and can it be removed?
I saw a video of someone changing the BGA chip at home, has anyone done this with the A1 SE?


Thank you for any help!

@mrluff

IIRC, A1SE has CPU on a card on a megarray connector...

Have you checked that the card is firmly on the connector?

@KimmoK

Hi KimmoK, no this is the AmigaOne G3-SE 750CXe@600 Mhz with soldered on CPU. I saw this guy on Youtube that changed a BGA chip, so I don't think it's impossible, should it be fried, but painstaikingly work and you need some equipment (which I think I can fix).

Getting the serial debug set up can be a bit tricky.
The "normal" connection has a male 9 pin at each serial port, that part is easy, but the cable between them must be a "Null Modem Cable", which has some pin pairs swapped.
The tricky part is that you can not tell if a cable is straight or null without having a meter on hand. The two cable types look identical otherwise.(both ends female)

Without a meter the best test is to connect two known-good serial ports to verify your cable and connections first, and only after proving those out should you move on to the machine in question.
There is a detailed article on setting up for serial debug at the AmigaOS Documentation Wiki. Link is provided below.
http://wiki.amigaos.net/index.php/Advanced_Serial_Debugging_Guide

Good Luck!
LyleHaze

[edit] spelling errors.

@LyleHaze

Hi LyleHaze, thank you for the info., I actually just made a null-modem cable here now, with the three wires only, soldering 2-3, 3-2 and 5-5 on the DB9, I get no output (tested the cable with meter first).

I take it is the DB9 on the AmigaOne that is for debugging and not the DB25?

I used putty with 9600/115200, 8 bit, no parity, 1 stop bit and no flow.


Questions:

- Should the small fan/rib on the CPU get hot if it works? It doesn't. The only chip I feel is getting warm is the Articia S.

EDIT: I got the rib/fan off, it was actually glued on (!), yanked it off carefully with a screwdriver.. It's dead cold, now what? Has anyone experience in changing BGA chips? :)
I have seen it done on youtube, and I have some experience with soldering myself, plus a very experienced friend.


- Should the keyboard and ethernet blink on power-on if CPU is fried? They do blink.
- Could it be that it's the ROM that is deleted because of no battery over a long period of time?

EDIT: se over.