dead Falcon

[sety]

Any idea why it won't switch to 16mhz and stays at 8mhz...?

Because CPU is halted or reset is high. I've had this with bad reset switch, bad ram and poorly seated TOS. It's very difficult as diagnostic cartridge is useless when it's dead like this. You mentioned your CPU is hot. It shouldn't be. Try emptying a can of HFC on to it before powering it up. If it comes good, you know what to change.

It've found it's helpful to keep some multimedia speakers connected as when the CPU starts (about 1-2 seconds after power up), even if the screen is dead, you get a loud and satisfying *pop* on the speakers, at the exact time it switches to 16Mhz.

Do you know the machine's history?

[damanloox]

The thing is that reset and halt signals seem to be correct (see previous posts) - reset switch was faulty but I replaced it and it's all ok now (ie signals on cpu).
As for he history - I'm pretty sure cpu has been replaced at some point and that chip mentioned above has been tinkered with.
I'll replace that chip and see what happens... Replacing cpu will be a challenge as I don't have correct stencil and I can't really see how I could put some paste on these tiny pads "manually"...

[sety]

The thing is that reset and halt signals seem to be correct (see previous posts) - reset switch was faulty but I replaced it and it's all ok now (ie signals on cpu).

Sorry, I was really tired. No idea why I said reset high would be a problem but I think you know what I meant.

Replacing cpu will be a challenge as I don't have correct stencil and I can't really see how I could put some paste on these tiny pads "manually"...

This from this service manual:

Screenshot.png

I wonder if it would be possible to cut you a stencil on our laser cutter. I don't know if it would have that kind of resolution, but I'm happy to try it and post you the stencil if it works. MC68030 in 132Pin QFP is a standard library component in Eagle, so it would be easy just to make a small dummy board up with just the CPU pads and send it to a fab house just to get the stencil made. The up side is you'd get a pocket full of boards to practice on before you try it on your real Falcon

[damanloox]

I wonder if it would be possible to cut you a stencil on our laser cutter (...)

That would be the best Xmass gift in years

[Arne]

No need for a stencil if you want to solder QFP package. Just look at some youtube videos how other people do it. You just need standard soldering equipment plus 1.5mm .. 2mm desoldering wick.

[damanloox]

No need for a stencil if you want to solder QFP package. Just look at some youtube videos how other people do it. You just need standard soldering equipment plus 1.5mm .. 2mm desoldering wick.

Well... there's no need for a car if you want to walk for 100km... but it's certainly easier and faster with a car...
I've tried "soldering iron and a wick" method and it never as gool and fase (and easy) as with the stencil..

[sety]

I wonder if it would be possible to cut you a stencil on our laser cutter (...)

That would be the best Xmass gift in years

It won't be before Christmas

I will give it a shot when I get back to work next year (school holidays now) I don't know how much luck I will have, but it'll be fun trying. It'll want to be a well focused beam.

[sety]

No need for a stencil if you want to solder QFP package. Just look at some youtube videos how other people do it. You just need standard soldering equipment plus 1.5mm .. 2mm desoldering wick.

You guys been following the work of the necromancer on the FB group who revived a totally dead bird? (I mean *totally* dead, I suspect it was a CT60 PSU error, burned traces and all). using only drag soldering?

Very impressive stuff.