v2 Analog - Apple ][ VGA adapter build

[rubber_jonnie]

Ok, so first try and something isn't quite right...

First off, I get a clear and sharp splash screen:

PXL_20230413_103404153.jpg

So the RPi Pico is clearly working with the correct firmware, but once the machine boots, that's when things go a bit wonky, as is evidenced by Elite:

PXL_20230413_103700002.jpg

If I boot to something 'Texty' like ProDos, the main screen looks like this:

PXL_20230413_104515160.jpg

And the VGA looks like this:

PXL_20230413_104519881.jpg

There is a 'However' here though.

From what I understand there is a config program, something which I don't yet have a disk image for, so it may well have started in an incorrect mode (I think Adrian Black suggested this) so I need to find that and see how it all pans out before I start troubleshooting, but so far I'm reasonably happy with what's what.

[PhilC]

@rubber_jonnie that looks like a very good start.

[rubber_jonnie]

@rubber_jonnie that looks like a very good start.

Yeah, I think I'm pretty close TBH, just need the damn config software!!

[Tomswork]

@rubber_jonnie

Is this the machine that has the 80 column card problem ?

Tom

[stephen_usher]

That looks suspiciously like a one bit error on the address bus.

[rubber_jonnie]

@rubber_jonnie

Is this the machine that has the 80 column card problem ?

Tom

It is...

However the card needs to be configured and I don't yet have the software.

[rubber_jonnie]

That looks suspiciously like a one bit error on the address bus.

Yes, quite possibly, but I need to configure the card first and I can't find the software anywhere.

I think the MMU may be getting worse too, as I'm starting to get errors at other times too, even with the 80 column card removed.

I could really do with another Apple II or IIe for testing.

[Tomswork]

@rubber_jonnie

I'm not sure if the mmu from the ntsc systems work in the pal machines i have 2e board for spare parts will have to check the part numbers. This cards slots do have buffers on them ? The memory read for the vga card is the same over lap as the system memory base 16k i believe

Tom

[PhilC]

@rubber_jonnie id love to help with you fixing your machine but would be worried about me breaking mine too.

[rubber_jonnie]

Ok, so @PhilC @Tomswork as ever I appreciate your input!!

If you could have a look at the MMU I'd be grateful Tom, this is the part I have:

PXL_20230414_081924754~3.jpg

However I think you're right in that the NTSC and PAL parts are different.

Phil, no worries, I appreciate your offer but wouldn't ask you to put your machine in peril for mine.

However, I have good news regarding the VGA card. I spoke to the dev overnight via Github and he suggested that I check for solder bridges. I did, (I also did when I built it) and there weren't any, but I did find 2 loose pins. Now I'm sure I checked for loose pins, but I obviously missed these two, which were on 2 different level shifters.

So, I have resoldered them and it only bloody works!!! The picture is nice and sharp too :)

PXL_20230414_081032380.jpg

PXL_20230414_080951637.jpg

PXL_20230414_080922048.jpg

I also believe that the problems I had with the base machine are most likely due to condensation after using the freeze spray again, so I'm going to avoid it for now and just test the base machine with the VGA card and avoid mucking around with the MMU.