Atari ST green-screen dead power-on?

[blakespot]

I just got an Atari 520ST and when I power it on I get either a white screen w/ no disk activity or a solid green screen. What does the green screen mean? Thanks.

 

 

 

blakespot

[+Stephen Moss]

The only time I have had that happen is when I have incorrectly installed an ST memory upgrade/put my Falcon back together.

My guess would be that it stays white as TOS is not being loaded. The green screen could be a partial load as the desktop background is green. Try removing the case and screen then pushing down all the ICs that are socketed, it may be that the TOS chips are not correctly seated (or dirty contacts if the legs have tarnished) and so some memory locations are not being accessed.

Alternatively it could be a power supply problem.

[blakespot]

The only time I have had that happen is when I have incorrectly installed an ST memory upgrade/put my Falcon back together.

My guess would be that it stays white as TOS is not being loaded. The green screen could be a partial load as the desktop background is green. Try removing the case and screen then pushing down all the ICs that are socketed, it may be that the TOS chips are not correctly seated (or dirty contacts if the legs have tarnished) and so some memory locations are not being accessed.

Alternatively it could be a power supply problem.

I did some searching and found people talking about chip seating issues w/ this symptom - so I did the "front drop" drill and it didn't help. So I opened the unit up and applied pressure to each socketed chip. Did the trick.

 

 

 

blakespot