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Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:03 pm
by troed
Bus error loop?
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:12 pm
by 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 3650 times
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:14 pm
by exxos
Can you try /AS and the ROM OE signal ?
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:18 pm
by PhilC
exxos wrote: ↑Thu Sep 20, 2018 6:14 pm
Can you try /AS and the ROM OE signal ?
/OE stays at 5V the whole time
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:21 pm
by exxos
To confirm you are on pin 22 ? (pin 8 of LS11) ?
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:22 pm
by PhilC
exxos wrote: ↑Thu Sep 20, 2018 6:21 pm
To confirm you are on pin 22 ? (pin 8 of LS11) ?
yes pin 22
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:24 pm
by exxos
What do you get on LS11 pins 9,10,11 ?
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:26 pm
by PhilC
exxos wrote: ↑Thu Sep 20, 2018 6:24 pm
What do you get on LS11 pins 9,10,11 ?
9 3.2 - 4v
10 same
11 same all constantly high
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:29 pm
by exxos
Forgottenmyname wrote: ↑Thu Sep 20, 2018 6:26 pm
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 ?
Re: Forgottenmyname - Progress
Posted: Thu Sep 20, 2018 6:34 pm
by 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