DEC PDT-11/150 – Part 5. The new disk controller RAM arrived.

In the last post I had found a faulty RAM chip on the disk controller board and ordered a replacement from a supplier on ebay.

Well, the part arrived Today and one fitting, the error lights on the disk controller went out… For a while.

I can confidently say that we are past the RAM errors and it is trying to boot but the drive makes a lot of stepping type noises and doesn’t settle down for quite a while. Then the some LEDs on the main board and the controller board light up.

This is what we have this time.

This time, according to the manual, they don’t mean RAM error. This time they mean.

1, 4&5 on the main board.

This manual says that this “Verifies that the second pass of the disk drive diagnostic was successfully completed. If an error is indicated, refer to Table 5-4 for the possible fault indicators on the Disk Controller module test phase 2.”

1 on the disk controller.

The manual says “Verifies the position of the disk drive 0 head after a restore command is issued.” and the course of action is “Replace defective drive 0 or module.”.

Replacement isn’t an option so I’m going to have to go in and see what’s occurring.

 

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