[Coco] RGB to VGA boards, test equipment needed

[Gene Heskett]

On Monday 07 September 2015 04:34:09 Barry Nelson wrote:

> > On Sep 7, 2015, at 1:18 AM, coco-request at maltedmedia.com wrote:
> >
> > These should be adequate, but you didn't quote the asking price.
>
> You could click the links I added. :)  I do agree with your comments
> about the sound card solution being marginal at best for an H sync
> pulse. The V sync pulse however is around 60Hz and should show up
> better. The hardware below should be good enough for both though I
> would think.
>
> http://www.ebay.com/itm/Hantek-6022BE-PC-Based-USB-Digital-Storag-Osci
>lloscope-2-Channels-20MHz-48MSa-s-/271265189899?hash=item3f28aa500b
> $65.00
> Bandwidth: 20MHz; Sample Rate: 48MSa/s;
>
> Or this one
>
> http://www.ebay.com/itm/SainSmart-DDS120-Pro-20MHz-PC-Based-USB-Digita
>l-Storage-Portable-Oscilloscope-/300992154516?talgo=origal&tfrom=271265
>189899&tpos=unknow&ttype=price&ssPageName=STRK:MESE:IT $67.99
> Bandwidth: 	20MHZ
> Maximum sampling rate: 	50M/S

Either of those would do well if you were running windows.  But 
generally, linux support isn't there.  Everything but my coco's runs 
linux here.

I would point out one big gotcha to all these that I have seen so far, 
and that is that thru the usb cable they are powered by, you are 
permanently connected to a huge ground, so one cannot make measurements 
by connecting the probes ground lead to an ungrounded location in the 
device you are testing.  You will probably blow $omething if you do.

With the ds201, which has its own builtin rechargable battery, you can 
pull the usb cable and then measure whatever you want to, just make sure 
YOU don't complete the path to ground.  Mine will run for an hour or so 
before it gets too dim to see.

Cheers, Gene Heskett
-- 
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