exxos's Atari, Amiga & retro forum

PhilC wrote: 12 Sep 2023 17:13 @rubber_jonnie haven't found any under sockets on this board so far but have found a few soldered pins that were left too long and just about touching the one next to it, that and the case of the rust monster leaving his foot prints everywhere.

Once I’ve got this board booting again I’m sealing the whole thing with some pcb lacquer.

Hopefully the 8502 comes tomorrow.

rubber_jonnie wrote: 12 Sep 2023 21:43

PhilC wrote: 12 Sep 2023 17:13 @rubber_jonnie haven't found any under sockets on this board so far but have found a few soldered pins that were left too long and just about touching the one next to it, that and the case of the rust monster leaving his foot prints everywhere.

Once I’ve got this board booting again I’m sealing the whole thing with some pcb lacquer.

Hopefully the 8502 comes tomorrow.

I hate the poorly trimmed legs on parts, so unnecessary. Lacquer sounds like a great idea.

PhilC wrote: 12 Sep 2023 21:59 @stephen_usher uouve just described how all large chips were soldered in and a real pain yo get out.

PhilC wrote: 14 Sep 2023 13:42 My 8502 & MMU arrived today and have been fitted. I don't think the MMU made any difference at all but now with the new 8502 I have more address bus activity but some odities as well. For instance activity on A6,A8 & A10 but not on A5, A7, A9, I'm going to see what 74 chips are on the odd side of the circuit and see what happens.

the rom chips are also very warm, so since its an odd address bus fault it might be one of those?

rubber_jonnie wrote: 14 Sep 2023 13:47

PhilC wrote: 14 Sep 2023 13:42 My 8502 & MMU arrived today and have been fitted. I don't think the MMU made any difference at all but now with the new 8502 I have more address bus activity but some odities as well. For instance activity on A6,A8 & A10 but not on A5, A7, A9, I'm going to see what 74 chips are on the odd side of the circuit and see what happens.

the rom chips are also very warm, so since its an odd address bus fault it might be one of those?

Would be worth pulling the ROMs to see if the address bus improves.

PhilC wrote: 14 Sep 2023 15:19

rubber_jonnie wrote: 14 Sep 2023 13:47

Would be worth pulling the ROMs to see if the address bus improves.

There was some inconsistent improvement, so I am going to program up a few replacement roms and see what happens.

PhilC wrote: 14 Sep 2023 16:34 @rubber_jonnie There are pull-ups but I've checked all of those with the power off and they all pull up to 5V when pressing reset.