do you really need the metal shield?

[Zetr0]

Originally Posted by Sandro

the static electricity where you can damage a chip is a urban myth

While its unlikely one's tights and fishnet stockings would produce enough electricity to damage an ASIC chip - there is enough to damage the data stored on reprogrammable chips like EPROM's or CPLD's - while these are not inherent on a stock Amiga, its wise to know if you have an upgraded one that will probably do.

As long as one doesn't dress up "all special like" - for using the Amiga one should be fine =)

Originally Posted by Sandro

the shield is for RF interference, fact is that commodore exaggerated a lot specially on the A500 armored like a tank
I remember the A501 expansion was totally armored as if that small expansion produce huge amounts of emissions

The A501 and A601 are essentially Faraday Cages! I do not know why -

These products are massively over-engineered for a problem that simply doesn't exist, and even if it did in an extreme case - it could easily be solved with a couple of capacitors and resistor pull-ups, surely thats got to be cheaper than all that metal work?

[eXeler0]

Originally Posted by Zetr0

The A501 and A601 are essentially Faraday Cages! I do not know why -

These products are massively over-engineered for a problem that simply doesn't exist, and even if it did in an extreme case - it could easily be solved with a couple of capacitors and resistor pull-ups, surely thats got to be cheaper than all that metal work?

Its good to know that the A501 will survive a direct hit from lightning. :-)
Maybe thunderstorms were common around where the Commodore engineers lived. ;-)

Skickat från min HTC One via Tapatalk

[Zetr0]

@eXeler0

Either that or perhaps electricity was clearly a lot more noisy in its youth

[Thorham]

Originally Posted by Sandro

the static electricity where you can damage a chip is a urban myth

[paul1981]

Originally Posted by Sandro

the static electricity where you can damage a chip is a urban myth

the shield is for RF interference, fact is that commodore exaggerated a lot specially on the A500 armored like a tank
I remember the A501 expansion was totally armored as if that small expansion produce huge amounts of emissions

Urban myth? If that makes you feel better about static electricity then all is well for you! I've had nasty static shocks in the past with blue arcs from my fingers - I certainly wouldn't want a computer IC to be on the receiving end of that.

Also with vacuum cleaners - I've seen blue arcs simply from friction of air movement through pipe. It's very real I'm afraid.

As regards shielding, it's to keep RF from escaping. Turn your Amiga on and tune into LW and MW and then tell me there's no interference. Shielding must help a bit here with RF I'd have thought.

[Amiga1992]

Originally Posted by Toni Wilen

Same here, if metal shield was removed and CD mechanism was put back in normal location (not moved 10cm+ away from main circuit board), CD mechanism become really unreliable.

So you are saying the shield IS essential? Someone else said they didn't need it.
Any definitive answer to this? I never tried removing it or anything, probably because there's nothing for me to do inside the CD32.

[Jope]

Leave it in in the cd32, no difference in other amigas..

[ChrisUnionNJ]

Here in the states that was A FCC thing could not be sold
with out it if I recall the Pet got around it because it had
it's own monitor..

[Sandro]

Originally Posted by paul1981

Urban myth? If that makes you feel better about static electricity then all is well for you! I've had nasty static shocks in the past with blue arcs from my fingers - I certainly wouldn't want a computer IC to be on the receiving end of that.

Also with vacuum cleaners - I've seen blue arcs simply from friction of air movement through pipe. It's very real I'm afraid.

As regards shielding, it's to keep RF from escaping. Turn your Amiga on and tune into LW and MW and then tell me there's no interference. Shielding must help a bit here with RF I'd have thought.

yep static shocks is urban myth believe me
similar myth like if lightning can damage a TV or computer, such energy always goes to ground and skip everything in the middle it can't enter to any wire always go to the center of the earth

the static electricity : the arcs contain high voltage but very low amperage , it can't damage anything,
if you really want to damage hardware use a flyback transformer from a TV or crt monitor to create arcs with high amperage

and yes,you are right the RF modulators built in the A1200 and A600 generate lot of noise, I recommend unsolder those boxes

[Steve T]

I try to be careful about handling these things (helps I live in a humid climate) some pictures here of alleged ESD damage to IC's...http://www.mtarr.co.uk/courses/topic...tes/index.html

[ Show youtube player ]

[DopPie]

ESD is not an urban myth. The problem is the scale of things. The IC has small transistors that can be damaged by an ESD. The thing is it seldomly breaks down completely. It is just starting to behave funny.

The chances are slim. Most of the times there will be no problem. But you cannot guarantee it.

Ram used to be more vulnerable in the past. We had high speed fifo's die by just pointing at them.

So,I would even like the shield be in place. My A600 is missing its shield and would need modifications since the ACA620 is in the way.

The shield not only protects the outside from RF from inside. But also protects the PCB from influences from the outside.

I had a codec that just muted all its channels when an ESD was near. Just taking your sweater off was enough.

So, if your Amiga is acting strange.......who knows, it might have taken a hit.

A little exaggerated : [ Show youtube player ]

[Shadowfire]

As was said before, the shields are an FCC thing. They act as a faraday cage and stop EMI generated on the motherboard from escaping into the environment.

The shields aren't required for the computer to work, but they're required to pass FCC certification of radiated emissions (and therefore, be legally sellable in the USA).

Also, ESD is NOT a myth. Nowadays, IC's have protection diodes in the package which help divert any ESD on the I/O pins to the decoupling capacitors on the power rails, which means they are LESS susceptible to ESD (than 25 years ago), WHEN they are installed in a PCB with the capacitors. Bare IC's are very much still super-sensitive to ESD.

[idrougge]

The shielding both stops outside interference from disturbing your Amiga and your Amiga interfering with outside equipment.

Sometimes you really need it, sometimes you don't – with an A1000 turned on, you may have a hard time listening to the radio, for instance. With the Atari ST, picture quality is severely altered by the presence of the shielding, which is much heftier than on Amigas.

[robinsonb5]

Originally Posted by Shadowfire

The shields aren't required for the computer to work, but they're required to pass FCC certification of radiated emissions (and therefore, be legally sellable in the USA).

Indeed - and those emissions aren't purely hypothetical either. Back in the day I had a 3rd-party 512k RAM expansion in my A500, and with that installed the computer caused minor TV interference elsewhere in the house - there was a faint ghosted but stable pattern that would crawl slowly over the TV programme being watched.

[bebek]

Originally Posted by DopPie

ESD is not an urban myth. The problem is the scale of things. The IC has small transistors that can be damaged by an ESD. The thing is it seldomly breaks down completely. It is just starting to behave funny.

The chances are slim. Most of the times there will be no problem. But you cannot guarantee it.

Ram used to be more vulnerable in the past. We had high speed fifo's die by just pointing at them.

So,I would even like the shield be in place. My A600 is missing its shield and would need modifications since the ACA620 is in the way.

The shield not only protects the outside from RF from inside. But also protects the PCB from influences from the outside.

I had a codec that just muted all its channels when an ESD was near. Just taking your sweater off was enough.

So, if your Amiga is acting strange.......who knows, it might have taken a hit.

A little exaggerated : [ Show youtube player ]

What DopPie said . ESD is real. Unfortunately, ignorance is real too .

[Michael Sykes]

...minor TV interference elsewhere in the house...

Now we know why they named it RF shield and not just metal frame.
Never had such problems myself but, before removing the iron, one should consider that.

If damage to elecronic components by electrostatic discharges would not exist, don't you think the industry would save the money spent on all the protective stuff like wristbands,shoes,tables and bags?
Those guys try to save money on cheap toiletpaper and even coffe...

[Sandro]

Originally Posted by bebek

What DopPie said . ESD is real. Unfortunately, ignorance is real too .

yep ignorance is real when some morons believes in certain fake videos created by a pair of nerds

[Shadowfire]

Must be a troll, doubling down on the ignorance.

[glenn]

Originally Posted by Akira

In any case, it's useless, it's always been, and there just by regulation. German units didn't come with it for example.

No, I have opened a virgin (previously unopened) german A1200 and it sure had the shield.

But I agree that it's not of much use, I always remove it on A1200/500/600.


And the ESD myth discussion.. Ofcourse Sandro also know it's real..

[Daedalus]

Originally Posted by Sandro

yep static shocks is urban myth believe me
similar myth like if lightning can damage a TV or computer, such energy always goes to ground and skip everything in the middle it can't enter to any wire always go to the center of the earth

Personal experience says very differently after examining the remains of a TV antenna signal booster that was blown apart after a lightning strike to the antenna. I've also seen an IC blown to pieces in a modem on the receiving end of a lightning strike.

What the hell are you talking about? To lightning, all conductors are routes to ground as they're all very close to ground potential anyway. Mains cables, telephone cables, TV cables, anything. The dielectric strength of the insulation on any normal cable is far too low to keep lightning out.

the static electricity : the arcs contain high voltage but very low amperage , it can't damage anything,

Think about it: why do static arcs from your fingers hurt, and why can you feel them at all? That is current flowing through your body and affecting nerves.

It only takes a minute current to do damage to a semiconductor junction, static electricity is more than enough to do it if the conditions are right. Commonly you get a breakdown of semiconductor junctions, which means increased leakage current in transistors and reverse bias leakage in diodes, both of which are used extensively in digital logic. This can cause them to behave unpredictably, and in a computer you're depending on every single one of them behaving exactly as it should. It doesn't take much leakage over a damaged junction to turn a 0 into a 1.