From dfdafdfde1ce0ca3cb8bc2d4979791f8e1258ca3 Mon Sep 17 00:00:00 2001 From: Andreas Baumann Date: Sat, 15 Apr 2023 20:37:18 +0200 Subject: updated status and added PSU in IMC-2001 --- content/hardware/imc-2001.md | 43 ++++++++++++++++++++++++++++++++----------- 1 file changed, 32 insertions(+), 11 deletions(-) (limited to 'content') diff --git a/content/hardware/imc-2001.md b/content/hardware/imc-2001.md index 28c3f5f..7444f6e 100644 --- a/content/hardware/imc-2001.md +++ b/content/hardware/imc-2001.md @@ -9,30 +9,41 @@ This is an old Taiwanese Apple \]\[ / CP/M clone. # Status Trying to fix several issues: -- power switch made some hissing noises, it was not the switch, now - the original power is dead (and some transformers are humming). Ordered - a Apple 2 replacement PSU, waiting for it.. + +- 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 driver read floppies (both) but both don't write to floppies + (when copying in CP/M or creating a file), they work when formatting + a drive. Could be a side-effect of the PSU not working properly. - the lever moving the contacts between 40-character and 80-character mode for the CRT output is corroded, doesn't always make contact and produces a flickering image - 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 + +Fixed issues: + +- ~~power switch made some hissing noises, it was not the switch, now + the original power is dead (and some transformers are humming). Ordered + a Apple 2 replacement PSU, waiting for it..~~ + The new replacement power supply works like a charm, also replaced + the switch, as it was also unreliable - ~~sometimes I get into the monitor~~ - ~~lower-nibble bit 3 of the key being pressed is missing, unclear where it is lost, I suspect a bad register on the motherboard holding the current ASCII value of the key pressed or something similar~~. Replaced a bad 74LS257N, works now just fine. -- 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.. -- possibly much more -- the floppy driver read floppies (both) but both don't write to floppies - (when copying in CP/M or creating a file), they work when formatting - a drive. Could be a side-effect of the PSU not working properly. -Known things to work +Not fixed issues: + +- ~~The 220V fan no longer works.~~ + I just disconected it, I don't think, it really helps to cool the system. + +Known things to work: - The keyboard works electronically (8039 MCS-48 like CPU with a 2K EPROM) - the Rockwell R6502 CPU has a phase 0 clock and seems to go through @@ -44,6 +55,7 @@ Known things to work - I can boot from a Apple \]\[ CP/M 56k floppy and I get a prompt, now as the keyboard works and the CP/M on the 80-character card I can also assume the Z80 is working just fine. +- the 80-columns card (a Videx Videoterm or rather a clone of it) works just fine. # Images @@ -76,6 +88,15 @@ both connector are female per default): {{< figure src="/images/hardware/imc-2001/keyboard_cable.jpg" alt="PCB and controller" >}} +Old PSU: + +{{< figure src="/images/hardware/imc-2001/old_psu.jpg" alt="New PSU" >}} + +New PSU replacing the old crusty one (this is a standard replacement PSU for +Apple \]\[ from [Reactive Micro](https://wiki.reactivemicro.com/Universal_PSU_Kit)): + +{{< figure src="/images/hardware/imc-2001/new_psu.jpg" alt="New PSU" >}} + # Documentation This is the "Operation Manual for IMC-2001, version 2.01": -- cgit v1.2.3-54-g00ecf