Old eprom programmer help.

[daver2]

That should be fine - as long as it is a good connection.

Dave

 

[samib71]

The blue arrow i can move it right or left hand side, were it should be on the middle?

 

[daver2]

Now, put the oscilloscope probe tip ON THE GROUND CLIP and post a photograph of the oscilloscope screen.

Dave

 

[daver2]

The blue arrow i can move it right or left hand side, were it should be on the middle?

I am not bothered about this at the moment.

Dave

 

[samib71]

Blye arrow on top of the screen.

 

[daver2]

Blye arrow on top of the screen.

I don't care...

Dave

 

[samib71]

Pin 20 z80 after playing with setings.

 

[daver2]

Just for my benefit...

Manual for your probes: https://www.jameco.com/Jameco/Products/ProdDS/2189880.pdf.

Manual for your oscilloscope: http://myosuploads3.banggood.com/products/20211216/20211216034340DSO2512GUserGuideEN.pdf.

Dave

 

[daver2]

You are not doing what I have asked you to do...

Dave

 

[samib71]

Sorry for your time, i have to read the manual.

 

[samib71]

I think my scope does nt have 0v option i could nt find it.

 

[samib71]

I will post tommorow,
Have a good evenning.

 

[daver2]

Which is why I suggested connecting the tip of the oscilloscope probe to the ground clip in the first place.

Irrespective of what your oscilloscope has or has not, this will ALWAYS work...

I have just read the manual myself. Your oscilloscope only has AC or DC coupling. No ground setting.

Also, the specifications for the probes are pretty abysmal in X1 mode. Perhaps we ought to have them in X10 mode - providing the oscilloscope is smart enough to adjust the display for us...

Have a good evening.

Dave

 

[samib71]

Hi dave i m back , how would you like me to the scope, i put V on 1v time(s ns) ?
I made a lots of tests yesterday and i confirm that there is a signal which is present on pin20 of z80, it can be visible if i put for exemple settings 500ns 100mv if i put 1v the signal becomes a straigt line.

 

[daver2]

>>> I made a lots of tests yesterday and i confirm that there is a signal which is present on pin20 of z80, it can be visible if i put for exemple settings 500ns 100mv if i put 1v the signal becomes a straigt line.

What you are telling me is (effectively) that there is NO 'signal' on pin 20 of the Z80 apart from random noise...

This is why I suggested setting the Y sensitivity to 1 V/div and adjusting the 0V level to a sensible place so I can work out what the actual voltage is (I don't trust the numbers that are presented and I like to know where 0V actually is).

So, can you go back and do what I asked you to do in post #163 please?

Let us align the oscilloscope trace up so I know where 0V is - with some sensible reference (i.e. one major division up from the bottom of the screen with the sensitivity set to 1 V/div).

Dave

 

[samib71]

You asked me to set at 0v , the trace line should be on the butom.

 

[daver2]

Not on the bottom, but one major division up from the bottom.

Dave