Forgottenmyname - Progress

[troed]

Bus error loop?

[PhilC]

Channel one yellow is /AS blue is /DTACK

It is looping as Troed says, the Newb in me hasn't worked out why yet but once we have, I think we'll be right onto the bombs step again.

P.s. not learnt how to do screen captures on my scope yet.

20180920_180839.jpg (3.92 MiB) Viewed 4593 times

[exxos]

Can you try /AS and the ROM OE signal ?

[PhilC]

Can you try /AS and the ROM OE signal ?

/OE stays at 5V the whole time

[exxos]

/OE stays at 5V the whole time

To confirm you are on pin 22 ? (pin 8 of LS11) ?

[PhilC]

/OE stays at 5V the whole time

To confirm you are on pin 22 ? (pin 8 of LS11) ?

yes pin 22

[exxos]

yes pin 22

What do you get on LS11 pins 9,10,11 ?

[PhilC]

yes pin 22

What do you get on LS11 pins 9,10,11 ?

9 3.2 - 4v
10 same
11 same all constantly high

[exxos]

9 3.2 - 4v
10 same
11 same all constantly high

4V does seem a bit low oddly, should be near 5V really... what do you get on the power pins of LS11 ?

[PhilC]

My PSU needed a quick tweak, was running at 4.93 between 7 and 14 of the LS11 which was the same value on the floppy power connector