Timebase is just another way to say horizontal time per division, which
you are adjusting. BTW, your scope probably has an adjustment called
"trace rotation". Usually a hole where you poke a small screwdriver to make
the trace level instead of sloped like yours is.
I am not sure what to tell you. Your pictures show that nothing much is happening.
You should cycle power after switching into test mode. I assume that you did that.
If the CPU was hung up in the main loop, and then you change the switch, it might
have no effect.
If reset is high, and not glitching low, and the oscillator output pin has a decent
square wave or something close to it at 6 MHz, with good logic levels like 0 and 4V,
then the CPU should be running, and a lot more should be happening. Did you check
the power and ground pins to the CPU? That would have been the first step. I forget
to suggest that. Pins 40,26,5, 20, and 7 should all be checked with your scope since you
have one. And check the oscillator output pin with the scope to insure a good main
clock to the CPU. I think that is pin 2 (not the pin that you scoped earlier).
Bob
--------------------------------------------
On Tue, 7/5/16, noddyspuncture@hotmail.com [PolySix] <PolySix@yahoogroups.com> wrote:
Subject: Re: [PolySix] Another P6 with all LED's lit....
To: PolySix@yahoogroups.com
Date: Tuesday, July 5, 2016, 10:17 AM
I made a typo Bob... that should be 4.67v and 4.72v
(not 7.72v) on IC27 pin1...!
Cheers,Tom
---In PolySix@yahoogroups.com,
<noddyspuncture@...> wrote :
Hi
Bob,
I made two more
photos... of the DAC (IC27 pin1) and the T0 at the same
time.
Dual trace,
scope set to 2v and using DC trigger and tweaking the level
until the waveforms showed up. There is only one spot on the
level control where they show, it's quite
critical.
There are
two shots... one at 1uS time div and one at 50uS time
div.
Switching the
test mode switch doesn't make any difference to these at
all.
On my scope I
cannot find any 'horizontal timebase' switch so I
couldn't do that part... and the slope +/- switch
didn't seem to do much either, it only seemed to change
the brightness...!
I
also measured the voltages on these pins with my meter -
IC27 pin1 has 4.67v in normal and 7.72v in test modes. The
T0 pin1 has -9mV
Is
this info any good...?
CheersTom