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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: TimT on April 01, 2016, 11:48:21 PM

Title: A1200 troubleshooting
Post by: TimT on April 01, 2016, 11:48:21 PM: 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?
Title: Re: A1200 troubleshooting
Post by: Oldsmobile_Mike on April 02, 2016, 12:02:05 AM: 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! :)
Title: Re: A1200 troubleshooting
Post by: TimT on April 02, 2016, 12:34:50 AM: Yes there is video out "red, green, white, amber, ect "

Here is a Video of the computer trying to boot
https://youtu.be/NfkepaXdOYI
Title: Re: A1200 troubleshooting
Post by: Zardoz on April 02, 2016, 01:15:35 AM: might be having memory and or cpu faults.

http://wiki.classicamiga.com/Amiga_boot_error_code_colours
Title: Re: A1200 troubleshooting
Post by: TimT on April 02, 2016, 01:21:39 AM: it probably has displayed all the boot error colors!:lol:
Title: Re: A1200 troubleshooting
Post by: krashan on April 02, 2016, 07:25:52 AM: 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.
Title: Re: A1200 troubleshooting
Post by: TimT on April 02, 2016, 05:22:31 PM: floppy power connectors test good. crystal oscillator also is good
Krashan if I can't locate the problem I may try to reflow

(http://s24.postimg.org/as2smw6tx/IMG_0845.jpg)
Title: Re: A1200 troubleshooting
Post by: H1ghpuff on April 03, 2016, 06:05:26 AM: Try to get a pair of Diagnostic Roms. They can help alot with exact error unless the CPU has broken.
Title: Re: A1200 troubleshooting
Post by: mechy on April 03, 2016, 06:59:17 AM: 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.
Title: Re: A1200 troubleshooting
Post by: TimT on April 04, 2016, 02:46:58 PM: I did not know about Diagnostic Roms! just ordered everything I need to burn them! Thanks for the information.