Re: Apple IIgs Monitor

["Michael J. Mahon" <mjmahon@aol.com>]

Wolfgang wrote:
> > > PS; Would also solve the ugly radiation from the original Monitor.
> > > My Mac se and my eMac suffer from it.
> >
> >
> >
> > What kind of radiation do you mean?
> >
> > DF
>
> My Se is inches left to the IIgs, the eMac is a foot or so on the right 
> side.
> If I turn on the IIgs Monitor the Mac get a picture shifting right and a 
> black bar wandering from top to bottom in ca 5 sec. interval.
> The eMac CRT  just get somehow flickering.Not too bad but notable.

That's caused by the leakage magnetic field from the IIgs monitor.

It can be at power line frequency (power transformer) or at the
vertical or horizontal scan frequency (yoke or horizontal output
transformer).

A thin piece of magnetic shielding between the monitors will fix
the problem.  "Soft" iron or, better, high permeability magnetic
shield will work fine.

> Reminds me on my early days when I was working on automotive IC's.
> There was a test called Load Dump. The tester was basically a huge 
> Capacitor which was discharged through my IC's.
> Whenever I "dumped", all Monitors in the LAB would look like someone has 
> pushed the pictured to one side. Also all test circuits close to the 
> load dump tester behaved erratic. Well, whenever I did these test I had 
> the Lab exclusively as everybody else took a break.:-)

Another case of the raster(s) responding to the magnetic field
generated by the "dump" current.

-michael

NadaNet networking for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."