VAX 11/730 quickie

[Mike Ross]

(replies inline)

On Sun, Feb 21, 2016 at 9:27 AM, tony duell <ard at p850ug1.demon.co.uk> wrote:
>
>> Well I haven't figured out exactly what the problem was but I'm
>> embarrassed to report it was indeed serial comms finger trouble. I
>
> I have found that those little in-line RS232 testers with 7 or so bicolour
> LEDs monitoring the important signals are very useful when working on
> a machine with a serial terminal. If you get flickering on the TxD or RxD
> LEDs then it is sending something.

Yes and I usually use such; I have an assortment of things from inline
testers to breakout boxes to Tektronic analysers. But this hookup was
so simple and obvious nothing could go wrong.... (!)

>> could have sworn that VT220 was fine and the cable wired correctly...
>> but to cover all bases I tried it with a USB serial port on the Mac
>> that sits in the lab.
>>
>> It worked.
>>
>> First time.
>>
>> CONV011
>
> There should be a pause between the 'CONV0' and the '11' IIRC

Indeed that's how it comes up. Very short pause since I have most of
the memory out as part of potential gotcha elimination - and the last
two tests are memory tests IIRC; they take a little longer.

> You should then get 2 lines of read errors for DD1 and DD0 in that
> order. If you get a 'Device Error' then the TU58 controller is not
> responding at all, either it is not plugged in or it has serious problems.

Yep that was shown in the link I gave. In text it's:

CONV011
?27  READ ERROR DD1
?27  READ ERROR DD0
ROM>^C

?27  READ ERROR DD1
?27  READ ERROR DD0
ROM>

> I have 2 genuine 11/730 console tapes. Not that it does me any good, they
> both have dropouts and are shedding oxide. The output of the read amplifier
> in the TU58 is 'interesting' shall we say.
>
> I am currently rebulding a standalone TU58. My aim is to somehow find a good
> tape (the hard part) and then to dump an 11/730 console tape image to it. That
> means writing some kind of program to talk to the TU58 (another hard part).

I did wonder how one might go about writing a tape image to a physical
tape... I'm happy to get the thing loaded via the emulator for now -
but I'd like to get real working tapes eventually.

If it helps your 'hard part' I have at least a couple of brand new
TU58 tapes - still sealed in plastic wrap...

Mike

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