exxos's Atari, Amiga & retro forum

Yay!!!! At last! :-)

stephen_usher wrote: 28 Jun 2024 15:42 Yay!!!! At last! :-)

Hell yeah!!

I started this thread on 4th June 2021, so fixing it has taken 3 years!!!

:dizzy:

I guess that means I'm persistent...

I gave the ULA replacement something harder to play with:


So far not blown a gasket.

Well done !

:D

HigashiJun wrote: 29 Jun 2024 00:53 Well done !

:D

Thank you :)

I guess you need another ELK now to fit that spare ULA to :D

BennehBoy wrote: 29 Jun 2024 16:11 I guess you need another ELK now to fit that spare ULA to :D

Why, do you have one :)

OK, so the replacement ULA thread has been running and running over on Stardot, you can find it here: Mogwaay's ULA replacement and here: Dead Elk

Of interest was the flickery images in turbo mode, fixed by a 33pF capacitor on IC 11, a flip flop that is part of the PAL circuit feeding the modulator and composite and takes a signal from the 17.7345 Mhz oscillator.


RGB doesn't use this signal and is fine.

:dualthumbup: :yay2:

And the Electron has stopped displaying red over composite :pullhair:

It isn't the ULA as it happens with both the replacement and the original, however the RGB output is fine, and that derives colour directly from the ULA, and since composite gets colour indirectly from the circuit that provides colour to the modulator.

Since there is blue and green, I suspect that IC15 may have a bad or gate on the red input, so I will start my investigations there.