dead TT motherboard repair attempt

[jookie]

Okay, interesting thing... I got a working FPU (68882) from a friend, I've plugged it in the socket and suddenly the TT starts to boot - I can see the Atari logo, memory test.... Then it waits for a long time and ends with 2 bombs, but I'm still missing the DCU (UA01) on motherboard and no floppy or hard drive is connected.

I didn't expect the FPU to be required in TT to boot.

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[Steve]

Wow you're getting close now!!!

[stephen_usher]

I can't remember if TOS 3.06 bombs without a floppy or not. If you have one laying about you could pop one on I imagine.

[Cyprian]

TOS 2.x and 3.x needs floppy drive

[czietz]

TOS 2.x and 3.x needs floppy drive

TOS 2.06 does. TOS 3.06 doesn't. Proof: My TT with Atari TOS 3.06 booted to the Desktop without any drives whatsoever:

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[Cyprian]

ok, good to know

[czietz]

I didn't expect the FPU to be required in TT to boot.

As the TT was never sold without FPU, the TOS 3 developers did not bother checking for the FPU before using it.

[mikro]

That's even more interesting trivia, thanks czietz.

[jookie]

As the TT was never sold without FPU, the TOS 3 developers did not bother checking for the FPU before using it.

Okay, nice to know... This one seems to be sorted out by plugging in the new FPU.

TOS 3.06 doesn't. Proof: My TT with Atari TOS 3.06 booted to the Desktop without any drives whatsoever:

So I'll got some other problem, which won't be fixed just by plugging in the floppy...

[czietz]

So I'll got some other problem, which won't be fixed just by plugging in the floppy...

I did not test this on my TT, but I find it plausible that a missing SCSI DCU might cause a bus error while TOS is trying to boot from SCSI.