PhilC's H4 Mongrel edition build x 3

[PhilC]

Not much of an update but

Thanks to @Icky I have a logic analyser to help work out what's going wrong with my first board. I just need the time to get it all connected up.

I'll be starting on the SMT stuff on the next two boards as well, whilst carrying out the testing on the first.

I've got to get some more resistors ordered. Building the first board has cleared out my stocks of 33, 1k and 10k resistors and 1uf capacitors.

[PaulJ]

So @PhilC , what do you get? A white screen and no serial out with diagrom? Ya I ordered the SMT glue and mmu from Exxos. Will get it a try on the second board. Would like to clear up the DMA issue first though. We will see what happens.

[PhilC]

That's what I still get @PaulJ .

Real life taking up all my time at the moment

[PhilC]

So, as it turns out, my dyslexia is a pain in the butt, guess who put the wrong value caps in c85 and c86 and therefore had no clock signal the the MFP, yes, you guessed it Me.

So I have a diagrom serial output now, which is cool, so just got to fix the video etc, wish me luck.

[exxos]

So I have a diagrom serial output now, which is cool, so just got to fix the video etc, wish me luck.

Progress though :)

[PaulJ]

So, as it turns out, my dyslexia is a pain in the butt, guess who put the wrong value caps in c85 and c86 and therefore had no clock signal the the MFP, yes, you guessed it Me.

So I have a diagrom serial output now, which is cool, so just got to fix the video etc, wish me luck.

Nice find @PhilC , does the diagrom output all look good?

[PhilC]

15759067655791762065424929064746.jpg

@PaulJ yes it's all good, I've got a problem with my RGB it seems but its booting to desktop now, so I'm very happy.

[PaulJ]

15759067655791762065424929064746.jpg@PaulJ yes it's all good, I've got a problem with my RGB it seems but its booting to desktop now, so I'm very happy.

Ya, mine is also washed out but not as bad as yours. I normally use high def anyways so its not really much of a handicap. When I finish the second board and no one has posted a fix I'll take a look see. Have you tried the highdef?

[exxos]

We haven't looked into it yet.. but try changing the 75R resistors to 100R see if it helps. We think the brightness is way to high for some reason.

[PhilC]

And I finally join the working H4 club.

20191209_165110.jpg

I've used a 32mhz oscillator to get the board up and running, hence the score but will be acquiring one from a good old Atari store sometime soon :lol:

And in case you were wondering, I got mine running with a DIP CPU but it also works fine with a PLCC one.