14-05-2022, 05:01 PM
(This post was last modified: 14-05-2022, 05:54 PM by CheshireNoir.)
Hey everyone (and someone). I made some diagnosis progress today.
OK, so at an off list suggestion, I tried reverting my main board back to SRAM and dropping back on my PC85b core board on and all the glitches and video issues immediately disappear. I was happily doing BASIC apps and playing games without a hitch.
I also tried the RAM test rom and guess what? It flickers anyway! (I am also now confident about the RAM on my SRAM board. :-D )
So that gives us another point of information. It would suggest that it's either something confined to the 128k coreboard or it's something on the main board that's only used by the DRAM configuration.
I'm going to go and revert this main board to a DRAM configuration, as I figure at this point there won't be anything I can test without it being in DRAM setup.
Cheers!
Chesh
Ps. this post would have been sooner but I got distracted AGAIN by Kilopede.
Wouldn't you know it? I reverted it to being a DRAM main board and now the symptoms have changed. Still can't boot from disk, but now I can run the RAM test, which is passing happily for all 4 banks.
The RAM test comes right up and a quick reset later and it's scanning everything.
The "proper"† BN55 still boots to no sync. I can get into monitor but can't type anything, by pressing RESET while holding down the M key. Just pressing the RESET key a whole bunch of times gets me to what looks like a cursor but it won't read any tracks. (Oddly every now and again, it'll read a single track when I do this but only the one)
Cheers,
Chesh
†If anything about this monstrosity can be said to be "proper".
OK, so at an off list suggestion, I tried reverting my main board back to SRAM and dropping back on my PC85b core board on and all the glitches and video issues immediately disappear. I was happily doing BASIC apps and playing games without a hitch.
I also tried the RAM test rom and guess what? It flickers anyway! (I am also now confident about the RAM on my SRAM board. :-D )
So that gives us another point of information. It would suggest that it's either something confined to the 128k coreboard or it's something on the main board that's only used by the DRAM configuration.
I'm going to go and revert this main board to a DRAM configuration, as I figure at this point there won't be anything I can test without it being in DRAM setup.
Cheers!
Chesh
Ps. this post would have been sooner but I got distracted AGAIN by Kilopede.
Wouldn't you know it? I reverted it to being a DRAM main board and now the symptoms have changed. Still can't boot from disk, but now I can run the RAM test, which is passing happily for all 4 banks.
The RAM test comes right up and a quick reset later and it's scanning everything.
The "proper"† BN55 still boots to no sync. I can get into monitor but can't type anything, by pressing RESET while holding down the M key. Just pressing the RESET key a whole bunch of times gets me to what looks like a cursor but it won't read any tracks. (Oddly every now and again, it'll read a single track when I do this but only the one)
Cheers,
Chesh
†If anything about this monstrosity can be said to be "proper".
John "CheshireNoir" Parker
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One Dark Little Kitten
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One Dark Little Kitten