Lo and behold! That did it! Thanks, Mike!I may have suggested this, or may have forgotten, but once it is powered up, what happens if you briefly short (with a wire) CPU pin 1 (VSS) and 40 (Reset)?
So I guess I’ll need that cap
Lo and behold! That did it! Thanks, Mike!I may have suggested this, or may have forgotten, but once it is powered up, what happens if you briefly short (with a wire) CPU pin 1 (VSS) and 40 (Reset)?
Beers not necessary, though thanks for the thought
The 1uF 10v to 50v shouldn't be a problem (usually, uprating like that makes fitting it difficult!)protek wrote: ↑Thu Jun 04, 2020 6:08 am I swapped the capacitor. I couldn’t find one with 1uf 10V rating, so I went one with 1uF 50V rating, which turned out to be the same as the original was. The original’s packaging had darkened as if it had run really hot at some point.
The new cap didn’t solve the boot issue, though. Board #2 still requires several reset cycles to get a signal on the TV and eventually a proper display. I probed the reset signal and it stays constantly high.
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_____/~~~~~ (POWER)
______/~~~~ (RESET)
Well, the screen isn’t completely blank. There is some moving garble, not pure static but something that the TV isn’t able to sync with. Getting a stable, junky picture requires a few reset cycles.But it bothers me you say you get NO SIGNAL to the TV at power on, until some number of resets? The ULA never sees the reset signal (not connected), and runs from power on (all the time), so you should at least get a stable, but junk, picture when Oric doesn't start (like when the boards were first "broken"