ALPHA MODIFICATIONS

[PhilC]

I think you just like to keep me busy with my soldering iron

At least your keeping up, Not sure where the other 15 people have gotten to...

Me? I'd rather sensibly gone to bed

[rubber_jonnie]

I'm waaaay behind, on account of other priorities, work, home maintenance etc.

I'm kind of at the stage now thinking I should wait in order to apply all the fixes in one go to see how it turns out!!

I've barely touched an Atari in weeks now

Still, winter is coming,which means I should have more Atari time!!

[PhilC]

I can verify that those fixes work on my board too.

And as with Icky's my floppy doesn't want to play either.

Well done guys.

[PeteW]

I can verify that those fixes work on my board too.

And as with Icky's my floppy doesn't want to play either.

Well done guys.

Does your display do that periodic blanking like Ickys too or is your picture stable?

I've really enjoyed watching the progress of this from virtually no picture to a nearly functional machine in under 2 weeks

If I had a spare motherboard, I'd be well up for being a beta board customer!

[PhilC]

I don't remember seeing it flicker like on the video.

I will try running it again a little later on and see what happens.

I'm wondering if it's a difference in monitor type?

[exxos]

FLOPPY FIX

Fixies missing pull ups on the LS06 buffers (never were on any schematic either!)

Solder 10K resistors to either the IC on the bottom of the PCB, or the resistors in a row on top of PCB (which ever is easier).

For example solder a 10K resistor to the highlighted pins on the resistors, then solder the free ends to 5V (tap from pin 14 of LS7406)

1772f.jpg (92.28 KiB) Viewed 7369 times

[Icky]

FLOPPY FIX

Fixies missing pull ups on the LS06 buffers (never were on any schematic either!)

Solder 1K resistors to either the IC on the bottom of the PCB, or the resistors in a row on top of PCB (which ever is easier).

For example solder a 1K resistor to the highlighted pins on the resistors, then solder the free ends to 5V (tap from pin 14 of LS7406)

Here is a photo of my quick hack to get this up and running - a cluster of resistors tied to pin 14:

IMG_3115.png (1.38 MiB) Viewed 7364 times

[PhilC]

The stripes don't match up

Does it need to 1k? I'm running short on those by the looks.

[exxos]

Does it need to 1k? I'm running short on those by the looks.

No idea. I suggested 10K to Icky.. I guess almost anything would work, even 100K maybe .

[PhilC]

If you've kept up, your board should now look a little something like this

20180927_162013.jpg (4.05 MiB) Viewed 7318 times

P.s. not done the 16mhz mmu fix as it was optional.