RetrogradeSecond attempt to source some #MC6847 ICs for my #homebrewcomputer.
Previous ones didn't behave as expected in the test rig, maybe these will...
FFS. None of these are good, and this one has obviously been sanded down and re-labelled... 😡 Tired of this hit and miss game (mostly misses these day, it seems.)
天 Oğuz Meteer 天@Retrograde How are you testing if the chip works? Do you have a simple test circuit?
I have one lying around that I'm not using, but I have no idea if it works. If I could test it easily and it works, then I can send it to you if you want 👍
@ometeer Testing it in the simple breadboard rig shown on the picture (rough schematic below), and then probing it with the oscilloscope.
As a first sanity check, the horizontal and frame sync signals should give sensible output signals (i.e. around 15.7 KHz/60 Hz).
Second level test is looking for address bus activity, as the IC is addressing display memory.
Third level is probing the Y (luma+sync) video output - it should be possible to recognize the general shape of a composite video signal on the scope.
Thanks for the offer, if it works and you want to part with it, I'd be happy to buy it off you. :)
@Retrograde Ah, a simple test circuit. I'll try to hook up my chip this evening after work. And you have it for free, I'm not going to use it anyway. However, I would appreciate status updates on your #homebrewcomputer :)