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Thread: Commodore pet 3032 screen full of lines

  1. #91

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    Quote Originally Posted by daver2 View Post
    I'll live !

    Let's see if your NOP generator comes tomorrow...

    Dave

    Hi Daver2 how are you today?
    Now i have Nop finally

  2. #92
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    Jun 2012
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    UK - Worcester
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    Still had my headache yesterday and today. It is going now though. Going out to play golf tomorrow with some friends. Weather forecast looks good (for the UK at least)...

    Have you got your oscilloscope powered up yet? Have you calibrated/compensated the probe? There is a test point on the oscilloscope that outputs a fixed square wave. You connect the oscilloscope probe to the test point and adjust the probe (with the supplied trim tool) so that you get a nice squarewave displayed with no overshoot or undershoot.

    Does any of what I have written make sense (when you read the brief instructions) or not?

    So your nothing (NOP) turned up!

    Dave

  3. #93

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    Quote Originally Posted by daver2 View Post
    Still had my headache yesterday and today. It is going now though. Going out to play golf tomorrow with some friends. Weather forecast looks good (for the UK at least)...

    Have you got your oscilloscope powered up yet? Have you calibrated/compensated the probe? There is a test point on the oscilloscope that outputs a fixed square wave. You connect the oscilloscope probe to the test point and adjust the probe (with the supplied trim tool) so that you get a nice squarewave displayed with no overshoot or undershoot.

    Does any of what I have written make sense (when you read the brief instructions) or not?

    So your nothing (NOP) turned up!

    Dave
    Hi Daver2,
    i tested scope now in the test point...i attach picture so you can tell me if correct ok?
    Thanks!
    20190921_120439.jpg

  4. #94
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    That looks fine to me.

    You can move the trace up and down by using the Y position adjust (so you can both see the trace and the data textual display at the same time) or you can switch the textual display on and off. Try this so you become familiar with some of the basic controls.

    You will also want to look at changing the voltage per division (the vertical trace should get smaller or larger); adjust the time base (so you see more or less cycles on the screen); and adjust whether the oscilloscope triggers on the leading or trailing (positive or negative edge) of the waveform. You will also need to adjust the trigger point at which the oscilloscope will trigger on the waveform. These are the basic controls you will need to master.

    Dave
    Last edited by daver2; September 21st, 2019 at 02:40 AM.

  5. #95

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    Quote Originally Posted by daver2 View Post
    That looks fine to me.

    You can move the trace up and down by using the Y position adjust (so you can both see the trace and the data textual display at the same time) or you can switch the textual display on and off. Try this so you become familiar with some of the basic controls.

    You will also want to look at changing the voltage per division (the vertical trace should get smaller or larger); adjust the time base (so you see more or less cycles on the screen); and adjust whether the oscilloscope triggers on the leading or trailing (positive or negative edge) of the waveform. You will also need to adjust the trigger point at which the oscilloscope will trigger on the waveform. These are the basic controls you will need to master.

    Dave
    Yes Dave i know this because i
    I already had an old scope....
    If you want we can try to begin test on the pet....

  6. #96
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    Ok,

    I thought I would start at the basics first.

    Install your NOP generator then. I assume you remove your 6502 CPU and plug that into your NOP generator then plug the znaoP generator into the vacated 6502 CPU socket on the main logic board.

    Scope each pin on the 6502 CPU and note the frequency of each pin.

    If the pin is a fixed value, is it high or low?

    What we are going to check is that address line 1 is half the frequency of address line 0. Address line 2 is half the frequency of address line 2 etc.

    The waves should all look reasonably 'square' with the low value < 0.8 Volts and the high level > 2.4 Volts.

    You should then be able to chase the address lines through any buffers to the ROMs etc.

    Dave
    Last edited by daver2; September 21st, 2019 at 09:34 AM.

  7. #97

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    Quote Originally Posted by daver2 View Post
    Ok,

    I thought I would start at the basics first.

    Install your NOP generator then. I assume you remove your 6502 CPU and plug that into your NOP generator then plug the znaoP generator into the vacated 6502 CPU socket on the main logic board.

    Scope each pin on the 6502 CPU and note the frequency of each pin.

    If the pin is a fixed value, is it high or low?

    What we are going to check is that address line 1 is half the frequency of address line 0. Address line 2 is half the frequency of address line 2 etc.

    The waves should all look reasonably 'square' with the low value < 0.8 Volts and the high level > 2.4 Volts.

    You should then be able to chase the address lines through any buffers to the ROMs etc.

    Dave

    Thanks so much Daver2!

    So i must check every cpu pin....can i take picture for every pin?

  8. #98
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    It would be worth checking every CPU pin and noting down the frequency or high/low dc level at this stage.

    No need for pictures, unless you want to post one of the clock pin (phi 2) and address line 0 as a reference.

    Dave

  9. #99

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    Quote Originally Posted by daver2 View Post
    It would be worth checking every CPU pin and noting down the frequency or high/low dc level at this stage.

    No need for pictures, unless you want to post one of the clock pin (phi 2) and address line 0 as a reference.

    Dave
    Hi Daver2 i measured first 20 pin of 6502 but i don't know if it's correct...
    I setted 1V scale and 20ms and i read these:

    1:150HZ
    2:60/80HZ
    3:120/140HZ
    4:50/60HZ
    5:50HZ
    6:50/60HZ
    7:150/160HZ
    8:54HZ
    9:90/115HZ
    10:70/80HZ
    11:2KHZ
    12:1,1KHZ
    13:590HZ
    14:1,9KHZ
    15:1KHZ
    16:1,7KHZ
    17:140HZ
    18:180/200HZ
    19:100/120HZ
    20:70/80HZ

  10. #100
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    There is something wrong with those readings!

    Pin 1 should be 0V - so should be a dc level and not have 150 Hz on it.

    Similar for pin 8 - This should also be a dc level of +5V.

    Where have you connected the ground crocodile clip of your oscilloscope probe to on the PET?

    Dave

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