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Diffstat (limited to 'content/hardware/imc-2001.md')
| -rw-r--r-- | content/hardware/imc-2001.md | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/content/hardware/imc-2001.md b/content/hardware/imc-2001.md index 1060f1b..5aea3e9 100644 --- a/content/hardware/imc-2001.md +++ b/content/hardware/imc-2001.md @@ -10,9 +10,6 @@ This is an old Taiwanese Apple \]\[ / CP/M clone. Trying to fix several issues: -- ROM 1 with BASIC is broken (and gets really hot). This explains - the booting issues.. (will be tricky to get a replacement). The - board layout doesn't fit to the original ROM sizes too.. - the floppy drives read floppies (both) but they don't write to floppies (when copying in CP/M or creating a file), they work when formatting a drive on CP/M though. ~~Could be a side-effect of the PSU not working properly.~~ @@ -25,13 +22,25 @@ Trying to fix several issues: and produces a flickering image - the CRT is producing some flickering when turning the brightness nob, this should be fixable with some deoxit. +- there could be grounding/signal issues causing the flickering of the CRT + (stemming from the replacement PSU). - keyboard cable is broken, at least the data line - the paddle and the joystick connectors miss some legs for putting them into the sockets on the motherboard - possibly much more +- the keyboard reset line cannot be taken to ground on the keyboard, works + with shrtening ground and reset though just fine. Must be a bug on the + ICs of the keyboard controller or a broken trace. Fixed issues: +- ~~ROM 1 with BASIC is broken (and gets really hot). This explains + the booting issues.. (will be tricky to get a replacement). The + board layout doesn't fit to the original ROM sizes too..~~ + Got an AT28C256, no more frying of chips, Apple Basic prompt appears, + tested some commands and it seems fine. The 32k ROM has to be filled in + starting from 0x6000 with #E000-$EFFF and from $7000 with $D000-$DFFF. + If this ROM is ok we will see. - Reseated and deoxied all ICs, some of them were quite corroded, at least 3 more turned out to be bad. Sadly it didn't have an effect on ROM 1 not getting hot (must be something else). |