Dying A1200?

[Disparil]

Hi, I've been having trouble booting up my precious towered A1200. At first it occasionally failed to boot, but it started to become more and more usual for the machine to fail, and now finally it won't boot properly at all. Sometimes when booting the floppy disk drive doesn't wake up at all, and the computer won't even try anything. If the disk drive wakes up, then the Amiga tries to boot and even sends some signals through the Voodoo since the monitor activates, but no picture comes through.

The specs are: towered A1200 with IdeFix Express (2 hard drives and a DVD-Rom attached), Blizzard 1260 turbo (68060 + 64 MB), Mediator 1200 with Voodoo 3 and a Realtek ethernet card, Indivision scandoubler.

First I went after the PSU, since someone else had the same trouble and the culprit was the PSU. Changed the PSU from the AT version to a fully working ATX with adapter, but no change. Then I started systematically removing the extra parts between boots to see which one was the problematic one, and plugged the Amiga into the TV set to see if it would send signal from that port. Well, in the end I had only the Mediator (because I haven't got a true Amiga PSU and the Mediator is needed for the ATX power supply to work), a mouse and a keyboard attached. I even disconnected the floppy drive from the motherboard. The tv did flicker a bit every time I powered up, but in no stage a picture ever appeared.

I'll still have to test the board with a real Amiga PSU, but I guess it looks like the motherboards busted somehow. Or does anyone have any other suggestions?

[utri007]

Have your tried to give some extra power to mobo through to floppy disk power connector? I had a similar problem and it was solved with that trick.

Seems that power doesn't go properly from mediator to mobo.

[Disparil]

Have your tried to give some extra power to mobo through to floppy disk power connector? I had a similar problem and it was solved with that trick.

Tried it, didn't help :/

[carvedeye]

have you tryed stripping it down and rebuilding it? It worked for me when my towered 1200 wouldn't boot.

[Disparil]

have you tryed stripping it down and rebuilding it? It worked for me when my towered 1200 wouldn't boot.

Yeah, I took it apart to its bare bones but the damn thing still won't boot.

[nicholas]

Have your tried to give some extra power to mobo through to floppy disk power connector? I had a similar problem and it was solved with that trick.

Seems that power doesn't go properly from mediator to mobo.

That's most likely to solve the problem, had to do the same with my old mediator 1200 tower.

[nicholas]

Tried it, didn't help :/

Try cutting the adaptor off an old Amiga PSU and splicing it to the ATX PSU.

IIRC, on my old tower I had power from an AT PSU feeding three places: Mediator, Floppy power connector and the Amiga PSU inlet.

[Disparil]

But the machine worked properly before with the PSU connected to the Mediator, wouldn't that indicate that the fault is something else? I've had to install the Indivision a few times since it had the tendency to jump off if I moved the Amiga, and I always feared that the force inflicted on the mobo would break something.

[nicholas]

But the machine worked properly before with the PSU connected to the Mediator, wouldn't that indicate that the fault is something else? I've had to install the Indivision a few times since it had the tendency to jump off if I moved the Amiga, and I always feared that the force inflicted on the mobo would break something.

That's a possibility, although you could have just been lucky that it was working with less juice before.

Mine was worked before I spliced the third connector but it was flaky at the best of times and would refuse to boot quite often or just lock up for no apparent reason too, which is why I performed the modification.

It's worth a shot.

[Disparil]

Mine was worked before I spliced the third connector but it was flaky at the best of times and would refuse to boot quite often or just lock up for no apparent reason too, which is why I performed the modification.

Thanks, I'll look into it.

[koshman]

Even if it (god forbid...) comes to the worst and your mobo needs replacing it wouldn't be a big deal as those are still quite plentiful and cheap. As long as your Blizz and Mediator are good, all is good I myself sometimes wake up screaming when I get nightmares about my B1260 failing

[nicholas]

Thanks, I'll look into it.

If it comes to the worst and your mobo its fried you can get a second hand replacement for around £40.

I have two spare ones for emergencies.

[Disparil]

Yeah, I have 2 A500's and 2 C64's as backup if the main ones fail, but I haven't gotten around to getting spare A1200's Well, now I ordered a used A1200 motherboard so that I'll have a fallback if the power trick won't help my poor dead machine.

[Disparil]

Update: Splicing the adapter from an Amiga PSU didn't help either. Luckily I should get a new (well, used) A1200 motherboard next week. If that doesn't work, then I'm soooooo out of luck

But thanks to everyone for suggestions!

[Disparil]

UPDATE: I got the spare motherboard, and... I found the culprit. The 3.1 roms! The new motherboard had 3.0 roms and booted, but when I switched the 3.1 roms from the old one, it didn't work at all. The old one worked fine when I installed the 3.0 roms. So, both boards work with the 3.0 roms, but neither work with the 3.1's. I already ordered new 3.1 roms so all should be well soon

Weird though, I would've never thought that the rom chips could fault like that. Has anyone ever encountered something like this?