Amiga RF shield corroding or tarnished?

PowerPie5000 · 21 March 2009, 21:39

Just opened up my A1200 for the first time in years and i have noticed the metal RF shielding is not as shiney as it used to be

(same with my old knackered a500).

I don't understand how this has happened as all my systems are kept in mint condition and have never been stored in a loft or garage? My house is usually quite warm and never gets cold or damp

Its not rust either... it looks like the metal has tarnished or oxidized and i don't think its corrosion? I have noticed a few amiga's that have this happening to the metal shields so i guess it's a common thing

Instead of it all being nice and shiney the metal shields have dull grey patches

Anyone else have this problem and know why it happens??

prowler · 21 March 2009, 21:51

Hi PowerPie,

I guess this is because the RF shield is not chromium plated, as it might appear when new, but tin plated. Tin plate is used because it's marginally softer than chromium plate and won't be so likely to peel from the base metal, which can be a problem with chromium plating.

Tin isn't quite so inert as chromium, so is less resistant to tarnishing. Of course, the shield might well be solid tin, but I don't think it can be because tin is actually very expensive.

A better (and more cost-effective) solution these days would probably be nickel plating.

prowler

PowerPie5000 · 21 March 2009, 21:57

So i guess it just goes this way as it gets older? I have always assumed systems have been left in damp/cold conditions when i see this

but mine have always been stored well.

I assume alot of people have the same issue with the metal shields in their amiga's?

Well i can solve that problem by buying some new shielding or doing a bit of handy work with some primer, car spray paint and lacquer

PWLM · 21 March 2009, 22:03

Any moisture from the air that settles on it will have a negative effect - a tin can will still get some corrosion on it even if it's left indoors. Also my machine went this way after a few house moves, probably because of plugging and unplugging cables, which eventually strips into the plating.

prowler · 21 March 2009, 22:04

Quote:

Originally Posted by PowerPie5000

I assume alot of people have the same issue with the metal shields in their amiga's?

Yes, we'll all have that problem in the end.

Quote:

Originally Posted by PowerPie5000

Well i can solve that problem by buying some new shielding or doing a bit of handy work with some car paint and lacquer

There really is no 'problem' to solve. Eventually, after many, many years, the shield will end up black, rather like old silverware. In conditions like you have described, this oxide layer will give it a 'black anodized' look, which is not unattractive and a lot more stable than acrylic paint or lacquer.

prowler

PowerPie5000 · 21 March 2009, 22:10

Ok i will scrap the paint idea then

as long as the sheilding is doing it's job then all is fine

its only cosmetic and i rarely open up my systems anyway so don't have to see it again (unless i have to for some reason

)

so it's nothing to worry about

rkauer · 21 March 2009, 23:42

There is a way to make the tin become as new, but it is dangerous and expensive:

You just need to force hot hydrogen trough the corroded area and a reaction will take the oxygen from the board in form of evaporated water.

Why dangerous? Because hydrogen is explosive!

Think "big baddabuuuuum"!

Amiga1992 · 22 March 2009, 00:25

I still don't understand why people want to keep this thing.
Remove it and e done with it!

prowler · 22 March 2009, 00:32

Quote:

Originally Posted by Akira

I still don't understand why people want to keep this thing.

Hi Akira,

It provides somewhere to mount a hard drive if you don't have the drive cradle which comes with the HD version.

prowler

Charlie · 22 March 2009, 00:51

I love my RF-Shields:

Once they're done slicing holes out of my fingers I re-cycle them as useful bits of metal for other projects...
...HDD / floppy brackets, the occasional IO shield.

I don't think I own a single computer with an intact shield.

rkauer · 22 March 2009, 03:34

Of course, none of my Amigas have the upper part of the shield from a very long time...

DC33 · 22 March 2009, 04:52

Truth be known, I don't think the shielding has any effect to or from the amiga itself other than "maybe" reducing the interference to my AM radio dial when in use.... but then again I wouldn't know if there is any difference as I too don't use the shield !!!

rkauer · 22 March 2009, 08:24

Wedge Amigas already have the metal on the back of the keyboard, so why another tin ware inside?

prowler · 22 March 2009, 08:42

Quote:

Originally Posted by rkauer

Wedge Amigas already have the metal on the back of the keyboard, so why another tin ware inside?

I think Charlie has already given the answer to this question above. Commodore must have known what a bunch of hackers the Amiga community would evolve into.

Jope · 22 March 2009, 09:17

Because of FCC.

Yoto · 22 March 2009, 12:27

Indivision Aga Scandoubler mounting instructions advice the use of the top RF shield, in their opinion, the computer will suffer from random crashes and RF interference can affect Indivison´s signal.
Anyone experienced this?

asm1 · 24 March 2009, 17:12

Quote:

Originally Posted by Yotoxionomai

Indivision Aga Scandoubler mounting instructions advice the use of the top RF shield, in their opinion, the computer will suffer from random crashes and RF interference can affect Indivison´s signal.
Anyone experienced this?

Nope. Run my indy without top RF shield and a CF card sitting on top of it (Brutalized the RF shield bigtime

) No "random crashing" or other crapness... plus no RF shield makes the miggy innards easy to get to

Andrew

gibs · 02 August 2011, 12:29

Quote:

Originally Posted by Yoto

Indivision Aga Scandoubler mounting instructions advice the use of the top RF shield, in their opinion, the computer will suffer from random crashes and RF interference can affect Indivison´s signal.
Anyone experienced this?

And ACA630 to remove it...

21 March 2009, 21:39	#1
PowerPie5000 Miggy Ate My Hamster! Join Date: Nov 2008 Location: Lancashire, UK Posts: 1,566	Amiga RF shield corroding or tarnished? Just opened up my A1200 for the first time in years and i have noticed the metal RF shielding is not as shiney as it used to be (same with my old knackered a500). I don't understand how this has happened as all my systems are kept in mint condition and have never been stored in a loft or garage? My house is usually quite warm and never gets cold or damp Its not rust either... it looks like the metal has tarnished or oxidized and i don't think its corrosion? I have noticed a few amiga's that have this happening to the metal shields so i guess it's a common thing Instead of it all being nice and shiney the metal shields have dull grey patches Anyone else have this problem and know why it happens??

22 March 2009, 00:51	#10
Charlie . . Mouse . . Join Date: Jun 2005 Location: Nowhere Age: 55 Posts: 1,792	I love my RF-Shields: Once they're done slicing holes out of my fingers I re-cycle them as useful bits of metal for other projects... ...HDD / floppy brackets, the occasional IO shield. I don't think I own a single computer with an intact shield. Last edited by Charlie; 22 March 2009 at 00:58.

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21 March 2009, 21:51	#2
prowler Global Moderator Join Date: Aug 2008 Location: Sidcup, England Posts: 10,300	Hi PowerPie, I guess this is because the RF shield is not chromium plated, as it might appear when new, but tin plated. Tin plate is used because it's marginally softer than chromium plate and won't be so likely to peel from the base metal, which can be a problem with chromium plating. Tin isn't quite so inert as chromium, so is less resistant to tarnishing. Of course, the shield might well be solid tin, but I don't think it can be because tin is actually very expensive. A better (and more cost-effective) solution these days would probably be nickel plating. prowler

21 March 2009, 21:57	#3
PowerPie5000 Miggy Ate My Hamster! Join Date: Nov 2008 Location: Lancashire, UK Posts: 1,566	So i guess it just goes this way as it gets older? I have always assumed systems have been left in damp/cold conditions when i see this but mine have always been stored well. I assume alot of people have the same issue with the metal shields in their amiga's? Well i can solve that problem by buying some new shielding or doing a bit of handy work with some primer, car spray paint and lacquer

21 March 2009, 22:03	#4
PWLM He found it at the zoo.. Join Date: Jun 2008 Location: Townsville / Australia Posts: 151	Any moisture from the air that settles on it will have a negative effect - a tin can will still get some corrosion on it even if it's left indoors. Also my machine went this way after a few house moves, probably because of plugging and unplugging cables, which eventually strips into the plating.

21 March 2009, 22:10	#6
PowerPie5000 Miggy Ate My Hamster! Join Date: Nov 2008 Location: Lancashire, UK Posts: 1,566	Ok i will scrap the paint idea then as long as the sheilding is doing it's job then all is fine its only cosmetic and i rarely open up my systems anyway so don't have to see it again (unless i have to for some reason ) so it's nothing to worry about

21 March 2009, 23:42	#7
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	There is a way to make the tin become as new, but it is dangerous and expensive: You just need to force hot hydrogen trough the corroded area and a reaction will take the oxygen from the board in form of evaporated water. Why dangerous? Because hydrogen is explosive! Think "big baddabuuuuum"!

22 March 2009, 00:25	#8
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,646	I still don't understand why people want to keep this thing. Remove it and e done with it!

22 March 2009, 03:34	#11
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	Of course, none of my Amigas have the upper part of the shield from a very long time...

22 March 2009, 04:52	#12
DC33 Zone Friend Join Date: Sep 2006 Location: Bathurst Australia Posts: 278	Truth be known, I don't think the shielding has any effect to or from the amiga itself other than "maybe" reducing the interference to my AM radio dial when in use.... but then again I wouldn't know if there is any difference as I too don't use the shield !!!

22 March 2009, 08:24	#13
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	Wedge Amigas already have the metal on the back of the keyboard, so why another tin ware inside?

22 March 2009, 09:17	#15
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,865	Because of FCC.

22 March 2009, 12:27	#16
Yoto 1 Potato to Spam´em all! Join Date: May 2008 Location: Lost in a Wine Country Age: 48 Posts: 572	Indivision Aga Scandoubler mounting instructions advice the use of the top RF shield, in their opinion, the computer will suffer from random crashes and RF interference can affect Indivison´s signal. Anyone experienced this?

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