RL02 Spinup fails

Jerry Weiss jsw at ieee.org
Sat Nov 11 16:33:00 CST 2017

> On Nov 11, 2017, at 2:42 PM, Aaron Jackson <aaron at aaronsplace.co.uk> wrote:
>> Aaron,
>> Do not underestimate the need for termination, even with a very short external cable.
>> When you factor in the internal cables runs,  crosstalk or signal reflections which interfere
>> with operation may still be present, especially when data transfers start.
>> If you have access to another bootable drive (8inch floppy?), suggest you load the
>> XXDP+ diagnostics for RL Drives.
>> Jerry
> Hi Jerry, thanks for the information.
> I had built several terminators, but being terrible at geometry I always
> did something wrong. I have now fixed one of the terminators I built. I
> had pins 1 and 40 mixed up, the rest of the terminator is basically a
> mirror copy.
> Unfortunately I still have the same error.
> I have an RX02 drive but no controller yet, so I'll have to continue
> investigating in the dark.
> Thanks,
> Aaron.

I too have had home built cables cause me grief because
of confusions around pins, keying or just being cable to properly fasten the

Could elaborate a bit on this part of your earlier message.

> I managed to boot into XXDP today using tu58em and ran the RLV12
> controller test. It seems though that the version of XXDP I loaded does
> not support the 22bit address (17774400) and defaults to the 16bit
> address (174400) so it just shows errors for everything.

VRLBCO expects 16 bit addresses for hardware setup.  Most of the 
XXDP diagnostic programs understand the 16 bit address for IO page
type devices.   

Separately, if this diagnostic itself is not able to use 22 bit memory 
on an 11/73 with 1MB ram, then you may have other issues.  It 
should not be tossing errors.  The fact that XXDP cannot boot
into extended addressing (XXDPXM) is not a good sign either.


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