Black screen amiga 1200

[Marcel21674]

I have a problem with my amiga 1200. It does not start up.
I have a black screen, the floppydrive gives no response and only de led of the harddisk is on.
Besides a harddisk, the amiga is totaly stock.
Tried the powersupply on my amiga 500, and it works fine, so i guess thats not the problem. ´
 
i'm afraid, it needs a new motherboard.......
 
Anyone an idea???

[Marcel21674]

Try removing the hard disk. Sounds like a hard drive fault to me, or a hard drive cable fault.

tried that, makes no diverence.

[Marcel21674]

Try unplugging the floppy drive. See if that makes it come ready.
Failing that, try reseating the Kickstart Roms.
Failing that, try replacing the Kickstart Roms (they could have turned bad).
 
BTW, is this a new Amiga. Have you seen it working before?

Got it a few months ago from some family.
It worked fine till yesterday. I was trying to unpack a LZX file, when suddely the 1200 made some strange noises and went black.
 
I had some flickering on de 1940 amiga screen before it shut down.
My amiga 500 doesn't have that flickering on de screen, maybe it was a sign?

[Marcel21674]

Start with the power supply, are the voltages there and close to +5,+12 and -5v?

Work from there, look for any leaking caps or bulged ones.

mech

The power supply is fine. Tested it on the amiga 500 and measured the voltages.
Can't find any burnt spots or other strange looking components.
The mainboard looks like new :huh:

Bought a replacement mainboard on ebay yesterday.

[Marcel21674]

It's alive!!!!!
 
I have replaced the motherboard and it works again.
 
Some guy from amigascene.nl (sorry, forgot his name), tested the old motherboard, and it's dead for sure.

[Marcel21674]

Don't let him throw it away though! I could do with the parts to resurrect other 1200s.. would be happy to buy it off for him for a reasonable price!

I still have the old motherboard. One of the chips probably has a short circuit, because it gets real hot.

[Marcel21674]

easy repair!:D
If it's broken put/buy a new one!

One chip is fried for sure, probably some other(s) to.
I'm not able to fix it, because of the smd technologie, so replace the motherboard is the only option.