Re: Weird distorted shapes

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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>>> chris@westnet.com
>>>
>>
>>
>

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Received on Wed Mar 5 10:34:29 2014