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NOT WORKING CBM 3032

Measure the pins of interest from post #92!

As I said previously, I am not interested in seeing the VDRIVE signal. I am only using it as a trigger.

If you monitor the HDRIVE signal when you press and then release SLOPE you may see a difference in what is displayed.

Dave
 
I would suggest looking at F9 pin 12 first.

Then post a photograph.

Your definition of noise may be indicative of the problem!

Dave
 
That's a signal...

Can you just go back to monitoring the HDRIVE signal please and posting a picture of that. Leave everything else alone (i.e. still triggering on VDRIVE).

Can you also make sure that the HDRIVE signal is stable on the screen please (i.e. the VDRIVE trigger is doing its job for us).

Dave
 
daver2 said:
That's a signal...

Can you just go back to monitoring the HDRIVE signal please and posting a picture of that. Leave everything else alone (i.e. still triggering on VDRIVE).

Can you also make sure that the HDRIVE signal is stable on the screen please (i.e. the VDRIVE trigger is doing its job for us).

Dave
Click to expand...
Ok!
 

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OK, Can you now look at F9 pin 9 next and take a photograph. This is the next lower address line to the character generator.

Do NOT adjust the oscilloscope IN ANY WAY unless told to... We now have all of our measurements relative (in time) to the VDRIVE signal - so we can compare photographs...

Dave
 
daver2 said:
OK, Can you now look at F9 pin 9 next and take a photograph. This is the next lower address line to the character generator.

Do NOT adjust the oscilloscope IN ANY WAY unless told to... We now have all of our measurements relative (in time) to the VDRIVE signal - so we can compare photographs...

Dave
Click to expand...
Ok
 

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I am not seeing what I am expecting to be seeing in post #109 on the lower trace (presumably F9 pin 9).

Can you do a short video please of this?

I would be happy if the signal is completely LOW, but I am not sure about why the trace is brighter on the left than it is on the right (unless it is an artefact of the photography).

Are you on ALT or CHOP incidentally?

Dave
 
OK, so that is permanently LOW. That is good and what I expected.

>>> no i haven t touched!

That wasn't actually what I asked! I was asking what the setting actually IS.

Dave
 
It needs to be on CHOP...

Can you change it please...

Post a video again of F9 pin 9 as a comparison please.

Dave
 
Thanks,

I can see a difference, but not in what you are measuring - which is good...

In ALT mode each individual trace is drawn separately. In CHOP mode the traces are drawn at the sane time, but the oscilloscope switches between the two very quickly. You can see that by the "dashed line" effect. I prefer CHOP to ALT mode myself.

Right, so note down the setting of the timebase now. If in doubt, take a photograph of the knobs and post them. You need to return to this setting later!

Next, slow the timebase down one click at a time (whilst monitoring F9 pin 9) until you just see some activity on the lower trace. Can you post a video of that please.

We are doing these steps very slowly and methodically so that you can keep up. This will, unfortunately, take us longer - but this way saves errors.

Dave
 
daver2 said:
Thanks,

I can see a difference, but not in what you are measuring - which is good...

In ALT mode each individual trace is drawn separately. In CHOP mode the traces are drawn at the sane time, but the oscilloscope switches between the two very quickly. You can see that by the "dashed line" effect. I prefer CHOP to ALT mode myself.

Right, so note down the setting of the timebase now. If in doubt, take a photograph of the knobs and post them. You need to return to this setting later!

Next, slow the timebase down one click at a time (whilst monitoring F9 pin 9) until you just see some activity on the lower trace. Can you post a video of that please.

We are doing these steps very slowly and methodically so that you can keep up. This will, unfortunately, take us longer - but this way saves errors.

Dave
Click to expand...
Thanks, with this setting i can see something:
 
That is a superb shot my friend!

Ok, keep the oscilloscope on those settings and monitor F9 pin 12. Post a photograph (or a video) of what you observe. If the trace is static, a photograph will be fine. If the trace is varying, it will probably need to be a short video.

Dave
 
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