CompuServe Messages

Ron, there may be a couple more changes to lower Rejuvenator noise, which helps everything else. It's all additive. I will Email you when I have a good solution. At least we are going in the right direction! I agree that Lucas is very finicky about U9 and Xtal freq. But it does seem to work OK (expansion bus stuff excluded) on long term diagnostics. One of the big problems with the A1000 motherboard is that it too has poor grounding of the 68000 and the expansion bus. There will be a picture with the buffer that shows where to put two wires on the motherboard that significantly reduces the impeadance of the VCC and ground traces to the expansion bus. There are two problems with the 68000 expansion bus in the A1000. The first is that the CPU data bus and address bus is heavily loaded. Secons is that it is not terminated. Both of these are problems with the A500 also. Noise can be caused by several things: Active devices, poor powersupply voltage regulation, improper signal routing and too long traces ( cross over noise and ringing), and poor signal drive. My expansion bus buffer will help in several regards. First, all address and data lines will be fully buffered, most clock and signal lines. This helps because the poor 68000 is loaded to limit in the basic machine. Secondly, it reduces the effective length of the bus, which limits transmission line effects to that of the base machine with no expansion devices. I will terminate the bus for additional help. The board will have a place to provide external power or use internal power. Assuming you make the two jumpers on the motherboard, I have no problems with poor ground or VCC. It will have more than enough capacitive decoupling to help prevent expansion bus noise from propagating too far into the Amiga. Commodore gave me an old ZorroI bus board for the A1000 and I put a 2058 on it. I noticed that the ground had significant noise on it relative to the Amiga 1000's ground, even though it was separately powered. This is why the motherboard jumpers are needed. If you want to see a joke, look at how VCC and ground find its way to the 68000 and tthe