by david
6. February 2011 12:18
After some fiddling and consulting of the KDJ11-D (CPU card) manual I've come to the conclusion that the message I was getting is nothing to do with boot failure, but a failure of the RAM chips on the board. If I start the machine with the HALT button pressed I can get into ODT (Octal Debugging Technique) and this should let me set values in memory directly. You just type the memory location and a forward slash / and the system tells you what is in memory there. You can then enter a new value. Typing the same location again with a slash should give you the value you have just entered. However, with my machine the values I put in seem to get garbled. This is a real setback, since my soldering skills are not good enough to replace all these RAM chips (there are 54 of them). But still I have found out a lot about ODT, and that is a good thing.
However, I can ignore these memory errors by pressing <CTRL+O>4<Enter>, this allows you to carry on regardless. So I installed the RQDX3 disk controller in slot two of the backplane and started the machine again, this time ignoring the RAM error and attempting to boot, but without a disk drive installed. This time you would expect a different message - I imagine that it should find the disk controller but complain that there is no disk drive. Here is the transcript of what I got:
KDJ11-D/S 4.55
Error, see troubleshooting section in Owner's manual for assistance
RAM VPC=024454 PA=17604454 00000000/104676 <> 177776
KDJ11-D/S> 4
Commands are Help, Boot, List, Map, Test and Wrap.
Type a command then press the RETURN key: BOOT DU0
KDJ11-D/S E.11
Drive error
Commands are Help, Boot, List, Map, Test and Wrap.
Type a command then press the RETURN key:
Not bad! It looks like it does indeed find the RQDX3 card and attempt to boot. If I install my RX33 floppy disk drive, I wonder if I'll get a slightly different message? That's got to be the next thing...
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