exxos's Atari, Amiga & retro forum

Hi,

My Falcon is now booting with a black screen. 12V and 5V from PSU in order. Floppy drive led(s) constantly lit and no activity.
Last thing I did was using bootconf to change the boot delay from 7s to 8s to get back the memory test upon startup, but now it does not start ....

I am thinking perhaps the NVRAM got messed up but booting with ALT-CTRL-RSHIFT-UNDO does nothing, same black screen.

I have the DS12887+ so there is no CLR pin to short it to GND and reset.

Any ideas how to deal with this? (hope it is not something else...)

You've probably just set the default video output to something you're not using, ie; VGA/RGB (selectable in bootconf) but one way to get around this is by hooking up your Falcon via RF and then fixing your settings again.

Did you mention whether your NVRAM has been replaced? If it is original it's probably either losing its settings or the settings could be getting corrupted.

There is also a Falcon nv-ram reset floppy disk image floating around somewhere... I've heard of people using that.

Yep in theory if the machine can be booted from floppy, reset the NVRAM and then warm-reset, the machine should wake up.

A dead NVRAM will usually keep settings while power is applied but lose it after a few seconds with power lost.

It's simpler if you can connect to an RGB monitor as suggested but if you don't have access to one, auto-booting a nvreset.prg + warm start should help.

Thanks for the tip on boot floppy. I found the app here (https://www.holmerup.com/trouble.html) that created a boot sector to reset my NVRAM.

On the same topic, how do I know whether I should change the DS12887+? I assume it's all about its internal battery, so if this is an original from 1992 (how can one tell?) than it might be time.

whomper wrote: 30 Jun 2025 12:27 On the same topic, how do I know whether I should change the DS12887+? I assume it's all about its internal battery, so if this is an original from 1992 (how can one tell?) than it might be time.

If it's still there from 1992, it's long past time :p they're basically all dead by now.

It's possible to do surgery on them and strap a lithium flat cell on top with a couple of wires - with the other option being to de-solder it and fit a socket. A word of warning though - desoldering ICs from the F030 mainboard is difficult without the right equipment and experience. Damaging the board in that area can cause some problems even if it looks like it is far away from important stuff.

A diagnostic cart resets the NVRam to its default values when poweron the Atari falcon or you can also try connecting PIN 18 of the NVRam module to GND. I think the 12887+ has a /Reset on pin 18 ...