Macintosh II error chime

[Aektann]

I've got a partially working Macintosh II board. Capacitors are surprisingly goog, however, I get an error chime on start. I tried to press reset/interrupt switches simultaneously and after that, I don't get any chime after startup at all. Could you please help?

 

[joshc]

Error chimes are usually RAM related. These machines can suffer from loose RAM SIMM sockets too. Best to start there I think.

Can you post a high res photo of the logic board please?

 

[Juror22]

As joshc inferred, start with reseating your RAM, be sure to check the sockets and you may have to clean the ram contacts. People these days don't pay as much attention to electrostatic precautions, but keep those in mind as you are handling the RAM.

 

[Aektann]

Thank you for answering. I’ve got all RAM modules and NuBus cards out and started a motherboard with the boot chime sequence coming again. Then I manages to get a working set of four 256kb SIMMs to boot the machine. The motherboard needs couple of fixes yet It is in great condition and running.

 

[Aektann]

Next trouble: suddenly the motherboard begins to startup immediately after connecting power cord. It looks like starting circuit is always on. What should I pay attention first?

 

[zezba9000]

Make sure this pin has a good connection. I noticed this was faulty on mine causing issues.

 

[Aektann]

Make sure this pin has a good connection. I noticed this was faulty on mine causing issues.
View attachment 33076

Good point, thank you! I'll check it.