[Coco] RGB to VGA boards, test equipment needed

[Gene Heskett]

On Sunday 06 September 2015 19:43:12 Kandur wrote:

> Thanks Gene.
> What I really need these toys for is, to check the video signal's sync
> pulses, amplitude, shape and polarity.
> Most of the time I would use these for to check audio signals.
> Do these have X and Y direct inputs, like the analog scopes do?
Rarely, and certainly not at that price point.

> I don't have room for large boxes anymore, like this
> Tektronix 7623A 100 Mhz Storage scope, I used to have in my shop.
> http://tinyurl.com/nbhla8n

The tek 7623 mainframe was a monster. The Hitachi link I sent weighs 
pehaps 5 or 6 lbs.  It is deep because the crt is long.  But it does 
have an xy facility, plus it measures both voltage and time, and by a 
1/x function, frequency although not good counter accurately.  A couple 
percentage points as its measuring the generated cursor lines overlaid 
on the waveform display.  I also have a 400 mhz dual trace digital 
sampler when I want to study a captured waveform in detail, but despite 
that, the hitachi is my goto scope.  I also have one of the ds201's, but 
it is not fast enough to show me the duty cycle of one channel of an 
A/B/Z quadrature encoder even at 200 revs, and it cannot show me the 
phase angle between the A/B signals, so once again the Hitachi gets 
taken to the shop.  To put that speed in perspective, an atom powered 
computer can follow that same A/B/Z signal without missing a pulse at 
spindle rpms north of 3000 revs. So the computer knows within 1.8 
degrees of rotation, exactly where the spindle is in its rotation so 
that it can take corrective action by sending more, or less power to the 
motor.

However, in order to do something we call "rigid" tapping, where the 
machine is moved in exact synch with the tap as it screws itself into 
hole, or back out, what is actually done is that the in or out of the 
hole motion is locked to the spindles instant speed.  So it will vary in 
unison with the spindles rpm.

Taps that are not stressed by shaky hand miss-alignment, last seemingly 
forever.  One fellow who makes some of the electrical stuffs we use has 
been tracking how many holes a 4-40 tap has threaded in alu, and that 
one tap is now past the 10,000th hole.  And the threaded holes look as 
if the tap was brand new right now.

> Kandur
>
> Sunday, September 6, 2015, 3:20:13 PM, you wrote:
> > On Sunday 06 September 2015 16:19:14 Kandur wrote:
> >> Would these pocket oscilloscopes do for checking video signals?
> >> If yes, wich one is better? Are there any others under $100?
> >>
> >> http://tinyurl.com/p9jx2ec
> >>
> >> http://tinyurl.com/ommymqs
> >
> > eye.
> >
> >
> >
> > above will, and because they are analog, often under priced on ebay.
> > I have one of these:
> >
> > <http://www.ebay.com/itm/Hitachi-V-1065A-Portable-Two-Channel-Analog
> >-Oscilloscope-100MHz-R-Type-w-Handle-/181840967212?hash=item2a5690f62
> >c>
> >
> >
> >
> >
> >
> >
> >
> > contains a good part you can use.
> >
> > Cheers, Gene Heskett
> >
> > "There are four boxes to be used in defense of liberty:
> >
> > -Ed Howdershelt (Author)
> > Genes Web page <http://geneslinuxbox.net:6309/gene>


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>