- USA issue-1 board, red solder mask/straight tracks.
- From the state of the soldering, it was clearly a USA kit built by someone. I have inspected and reflowed the entire board.
- I implemented the “basic” composite mode (transistor + 2 resistors), per these instructions: https://www.bytedelight.com/?page_id=3560
- Confirmed I see a composite video signal on pin 16 on the ULA (yes, I understand it’s a 2C184E which is not preferred but from all my research should work just fine with the composite mod).
- Confirmed same signal present on the center pin of the RCA output.
- I am using a known good Apple IIc 9” monochrome composite monitor.
- I’ve verified all voltage present on ROM, ULA, CPU, RAM and 5v into the composite mod.
- I’ve verified activity on the CPU data lines. But with more info, perhaps may need to recheck.
- The transistor I’m using, I’m doubtful given I see a signal of some sort coming out the RCA center pin (same as is visible on ULA pin-16).
- Some idiosyncrasy with the Apple IIc display? But it’s just a basic composite in monitor.
- Bad ULA — but then why would I see a composite signal on the scope on pin-16? Although concede, not sure what the correct signal should look like. I have TS1000 on the way, so can do a ULA swap soon and verify.
- Bad CPU?
If anyone else has ideas, or thoughts on other items to check the would be appreciated.
Thanks -Alan