Re: Weird distorted shapes

Rodger, could you expand on that a little so I can understand it more.

On Wed, Mar 5, 2014 at 7:34 AM, Rodger Boots <rlboots2@gmail.com> wrote:

> Try running WITHOUT R14 & R72.
>
> Doesn't look like correct parts are on the board. If these are low enough
> in value they could cause what you have.
>
>
> On Tue, Mar 4, 2014 at 2:44 PM, Joel Griffin Dodd <griffindodd@gmail.com>wrote:
>
>> Here's the full schem for the Deflection and HV...
>> http://www.dsbelec.iinet.net.au/Amp_Defl&HV_Schematic_Dez_FINAL.jpg
>>
>> And here is a high res photo of the deflection board if it is of any
>> help...
>> http://www.amazingarcading.com.au/2013_Proto-03.jpg
>>
>> Here's the parts list for the deflection board...
>> http://www.dsbelec.iinet.net.au/deflection_pcb_a201015.htm
>>
>>
>>
>> On Tue, Mar 4, 2014 at 12:39 PM, Colin Davies <
>> colin.w.davies@btopenworld.com> wrote:
>>
>>> As Clay says....
>>>
>>> To be more useful I'd want to see the schematic for the
>>> deflection section and/or the layout. Curvey/distorted things like that
>>> could be related to opamp speeds or outputs getting too close to the
>>> rails
>>> or L/C or maybe power...
>>>
>>> ----- Original Message -----
>>> *From:* Joel Griffin Dodd <griffindodd@gmail.com>
>>> *To:* vectorlist@vectorlist.org
>>> *Sent:* Tuesday, March 04, 2014 8:21 PM
>>> *Subject:* Re: VECTOR: Weird distorted shapes
>>>
>>> I spoke to Doug Snyder from Atari who, apart from designing the System
>>> II hardware, also worked on a fair bit of the XY drives and outputs for
>>> many of their games. He said that there was cross talk between the Axis
>>> which is what was causing the curving and to isolate a letter on the scope
>>> then measure the voltage change for a stroke to see if there are unwanted
>>> voltage changes in the direction of the stroke that should remain straight.
>>> If there are non then it could be the yoke, if there are then the concern
>>> is that there is cross talk in the XY drives.
>>>
>>> Trouble is I have no idea how to isolate the stroke of one letter on my
>>> scope as I'm not that proficient.
>>>
>>>
>>>
>>> On Tue, Mar 4, 2014 at 12:07 PM, Colin Davies <
>>> colin.w.davies@btopenworld.com> wrote:
>>>
>>>> The problem looks more apparent in this other picture... See how the
>>>> 'straight' lines have a curve to them...
>>>>
>>>> https://www.dropbox.com/s/i1r76l4dif9vv2w/2014-03-02%2020.10.19.jpg
>>>>
>>>>
>>>> ----- Original Message ----- From: "Clay Cowgill" <
>>>> c.cowgill@comcast.net>
>>>> To: <vectorlist@vectorlist.org>
>>>> Sent: Tuesday, March 04, 2014 6:46 PM
>>>> Subject: RE: VECTOR: Weird distorted shapes
>>>>
>>>>
>>>> >Look at this screen shot of another builders results...
>>>>>
>>>>>> https://www.dropbox.com/s/owa3vq5l6f0lgv2/100_3343_zps3521fb63.jpg
>>>>>>
>>>>>> Notice the blue is perfectly formed, but the green is all messed up
>>>>>>
>>>>>
>>>>> That looks to me as though the green channel amp is slow to turn on.
>>>>> The
>>>>> vectors look pretty straight-- they're just either 'fading in' (or
>>>>> 'fading
>>>>> out' depending on the direction of the draw I suppose) before reaching
>>>>> the
>>>>> end of the line. Could be a tube issue as well. Looking at the green
>>>>> color
>>>>> output vs. a deflection channel (or two) would probably show the
>>>>> problem on
>>>>> a scope.
>>>>>
>>>>> There might be a little high frequency 'jitter' in there somewhere
>>>>> that's
>>>>> causing the hash on some of the green verticals. Hard to tell with a
>>>>> picture-- really need video there. Also could just be that the shadow
>>>>> mask/dot pitch on the tube is pretty big and sometimes the green
>>>>> verticals
>>>>> are straddling the mask and appearing on one side or the other.
>>>>>
>>>>> For Joel's original problem, I would probably try to trace things
>>>>> through
>>>>> the deflection section with the scope-- put the Star Wars boardset X
>>>>> output
>>>>> on one channel and then follow X through the deflection section with
>>>>> the
>>>>> other channel. Set the volts/div to try to keep the waveforms about
>>>>> the
>>>>> same vertical size on the scope and compare them visually. You should
>>>>> be
>>>>> able to see that amount of difference/distortion on the screen so you
>>>>> should
>>>>> be able to see when it appears in the deflection board. (Hard to debug
>>>>> without knowing the design, but I'm assuming there's probably some
>>>>> sort of
>>>>> pre-amp that you could look at before it gets to a power-amp stage.)
>>>>>
>>>>> It does kinda look like its more prominent on short vectors which is
>>>>> probably a clue. To be more useful I'd want to see the schematic for
>>>>> the
>>>>> deflection section and/or the layout. Curvey/distorted things like
>>>>> that
>>>>> could be related to opamp speeds or outputs getting too close to the
>>>>> rails
>>>>> or L/C or maybe power...
>>>>>
>>>>> -Clay
>>>>>
>>>>>
>>>>> ------------------------------------------------------------
>>>>> ---------------
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>>>>> chris@westnet.com
>>>>>
>>>>
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>>>>
>>>
>>>
>>
>

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Received on Wed Mar 5 11:54:52 2014