Re: Use of digital oscopes when testing vector boards?

I've got a TDS210. Obviously the game isn't playable, but it's usable for
test and repair. At least you can look at it and say if the board is
outputting a picture.

You should be able to adjust the V/div and Voffset in order to zoom-in and
read text. In XY mode that scope samples at a fixed rate of 1 MS/sec, which
is about 13 samples per half-inch, which is generally enough to see what
it's doing. It's a little chunky or fuzzy when you're zoomed-out to see the
entire screen but you can get zoom-in to get more detail.

Yes the Z might be helpful but it's not everything; the next problem you'll
hit is persistence. Ideally you want something in the 10ms-100ms range to
approximate the fade of a CRT phosphor. My Tek has a few coarse levels like
1sec, 5sec, infinite so it's only useful for the static self-test screens.

-joey

On Mon, Jul 23, 2012 at 2:26 AM, David Shoemaker <davids@oz.net> wrote:

> I have a couple of old analog scopes (A tenma and a tek). The Tenma
> controls are getting tired and they are both kind of big to lug around to
> the back of a game. I picked up a Fluke scope meter 105b but it appears to
> not have an XY mode L****
>
> ** **
>
> I am thinking about getting one of the newer digital units (much more
> portable).****
>
> ** **
>
> Things like:****
>
> Atten ****
>
>
> http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=320949414562+&item=320949414562&vectorid=229466
> ****
>
> Rigol****
>
>
> http://www.ebay.com/itm/Brand-New-Rigol-Digital-Storage-Oscilloscope-DS1102E-100MHz-1Gs-S-2-Channels-/160848727649?pt=BI_Oscilloscopes&hash=item257354ce61
> ****
>
> Or a used Tek:****
>
>
> http://www.ebay.com/itm/Tektronix-TDS-1002B-/300746471312?pt=BI_Oscilloscopes&hash=item4605e2f790
> ****
>
> ** **
>
> I borrowed a TDS220 to try and the display from a battle zone was chunky
> but you could tell that the board was running. Couldn’t really read the
> rom error numbers. ****
>
> ** **
>
> I don’t see any of these having a z channel which would make them more
> useful for vector testing (to blank the display when beam is moving from
> line to line).****
>
> ** **
>
> The Atten and Rigol are both color models and they all appear to have the
> same 320x240 resolution.****
>
> ** **
>
> Any recommendations? Or opinions?****
>
> ** **
>
> Thanks,****
>
> David****
>

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Received on Mon Jul 23 09:52:12 2012