A1200 troubleshooting

[TimT]

Hi Everyone

I have two faulty A1200 motherboards one is definitely a Parts board the other I would like to repair.

The board I am trying to repair just displays " random colors " red, green, white, amber, ect.. then reboots. I can confirm power supply, Roms, caps are all ok. The board was tested " bare " no floppy, no Hd ect..

I have the tools to repair this but not the knowledge. can anyone point me in the right direction to troubleshoot this board?

[Oldsmobile_Mike]

No output on any of the video connectors?

Alice?

This sounds no bueno to me, but if you have tools and parts I guess you're looking at replacing at least one of the SMD chips?  Good luck!  

[TimT]

Yes there is video out "red, green, white, amber, ect  "

Here is a Video of the computer trying to boot
https://youtu.be/NfkepaXdOYI

[Zardoz]

might be having memory and or cpu faults.


http://wiki.classicamiga.com/Amiga_boot_error_code_colours

[TimT]

it probably has displayed all the boot error colors!:lol:

[krashan]

I would start with a hot-air reflow of the CPU, then continue to chip-RAM and if it does not help, AGA chips. I assume you have replaced all the electrolythic capacitors already (even if they look good). Checking PSU voltages (under normal load) is also worth trying.

[TimT]

floppy power connectors test good. crystal oscillator also is good
Krashan if I can't locate the problem I may try to reflow

[H1ghpuff]

Try to get a pair of Diagnostic Roms. They can help alot with exact error unless the CPU has broken.

[mechy]

Start with chip ram,which the green indicates and maybe work from there.

red can suggest bad or wrong rom. double check the numbers and make sure they are true 1200 roms. i have seen people try and swap other machine roms into amigas lol.

[TimT]

I did not know about Diagnostic Roms! just ordered everything I need to burn them! Thanks for the information.