Mix Computer Trouble Shooting

[Artur D'Assumpção]

Marc,

That's weird, because those computers (provided by SSL) never were meant to boot on paper, so that ROM should work out of the box, unless it was faulty. Also having 3 CPUs with the same ROM, they all must have worked at some point.

I agree that the scrambled screen is produced by the VDU/Graphics, but that's because it must be dumping the memory contents or something similar, and since it's not booting it finds garbage on the video buffer.

From the troubleshooting so far I would still pursuit something related with the floppy controller or drive, or the connection between them. Anyway replacing with a more recent ROM it's always another issue to clear.

Good luck!

Cheers,

Artur

[marcmozart]

Yes, we cleared that up now. All those CPUs allegedly bootet from 8"-Floppy Drives before.

Still in complete darkness, but working on it. Will keep you guys updated.

[Artur D'Assumpção]

Keep us updated!

[sintech]

Just checked another CPU here.. and it has the same Boot Rom as the other three Processors you have Marc.

CPU wise, the 430, the 490 and the 4100/A all booted from 8” floppy… no tape! no paper punch cards!

The 490 is the best option in terms of upgradeability, even over the 4100/A, which is imprisoned in the technology of it's fleeting 20 meg moment!

[matt]

Could be just too simple ..... but if I recall correctly from memory, I had the same problem which I overcame by changing the power-on sequence.
Can't remember which one was first - the computer itself or the desk.
I have the 3.5" floppy though.

Maybe worth a try if you didn't do it already.

Matt

[Artur D'Assumpção]

Hi guys,

I'm just posting a section of the Automation manual, just to keep things in perspective and accordingly to the SSL Manual:



Cheers,

Artur

[matt]

Ok - yesterday I restarted my desk after about a 1 year break ........ the computer came up fine .... the first time.

When I switched off the computer again, it didn't access the drives at all - got the scrambled screen that marc posted.
Then, I shut down the computer leaving the desk up and waited about 5 min restart with the same result : scrambled screen, no drive access.

I then decided that there are other things to care about as well and left the computer switched-off for about 1 - 2 hours or so.
Switching on the unit again made the computer boot fine without any problems.

I am just guessing here - but probably there's some kind of logic inside the computer, that keeps it from accessing the drives in case of fast on/off cycles ?

Matt

[xmax]

I have never worked with the big 8" drives, I pop the desks out before I turn off,
Turn the computer on, disk led flashes, then I put the disks in. As far as I have
seen, it does not matter if the computer or desk is on first.

I agree with above you should check all the voltages in the computer not its
power supply, also those things are full of tantalum caps which are famous
for shorting they are worth checking. reseating the chips can't hurt, but
make sure you work on anti-static mat. May the force be with you. N

[MikeSynthesizer]

What kind of ROM IC is it?  I suggest verifying the ROM first before trying to source another one if you have the tools available. 

[walrus]

Old information maybe, but I just found my (very) sketchy notes from my 6K training course.

" G Series 4/100 processor card has a 10-12 second delay before reset can be pressed. Processor has an
 Autoload line which is held off to let discs (8" that would be) get up to speed. Reset line is in Floppy power lead"

[marcmozart]

With Andy / sintech's help I have confirmed that my BUS DRIVER + KEYBOARD/VDU-Cards are working fine in other systems, but not the FLOPPY CONTROLLER-Card for the 8"-Drives that I bought, so next step is to return that and get another one.

[Artur D'Assumpção]

Occam's razor (also written as Ockham's razor from William of Ockham (c. 1287 – 1347), and in Latin lex parsimoniae) is a principle of parsimony, economy, or succinctness used in problem-solving. It states that among competing hypotheses, the one with the fewest assumptions should be selected. Other, more complicated solutions may ultimately prove correct, but—in the absence of certainty—the fewer assumptions that are made, the better.

[marcmozart]

The moment my SSL Mix Computer is working, will be similar to the moon landing for the United States! 

[perfectsnd]

Has anyone brought the 3 sandwich Total Recall Computer back from the dead? Is so let me, I would like to talk to you.

[marcmozart]

The computer that came with my console didn't have Total Recall. It's on the list of things to do, but not a priority.