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Salt water fish tanks and McIntosh amp

C

c_dk

Addicted Member
Just finishing a repair and refurb on a MC2155 amp and while it is heating up for a bias check I thought I would pass this along.

I sold this amp back in 1982 or '83, have put lamps in it before but it needed repair this time and of coarse a recap after 30 years.

The problem is that there is corrosion everywhere. Chrome surface rust, edges of transformer cases, even growth on some circuit card contacts.

I have posted in the past about "gifts" of ocean front equipment that were literary rusted throughout but our big pond to the west is fresh water and 30 miles away.

Turns out the client has many salt water fish tanks in the same room as his audio system. Do not know of any solution other than regular contact cleaning. Anything special that our ocean front friends do?
 
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That is pretty bad corrosion. I would suspect that it has a lot to do with the air ventilation in that room and the complete lack of 'keeping the stuff up.' I live four blocks from the ocean and never had an issue with any of my gear. I check and clean the chrome chassis every six months, and I don't ever have any rust. I do what Terry does and wax the chassis. I also sometimes put a super thin film of WD-40 on the chrome, and its not just because of where I live but also for long term safety. My stuff is like new.

I would suspect if you sold this thing back in 1983 and it has been locked away in this room for 27+ years without ever a detailing or cleaning then that is the issue. I have seen perfectly good gear go into storage in places that are pretty dry like Palm Springs and come out five years later with corrosion all over the chassis. I do not expect a chrome piece on an automobile to last 27 years without some sort of polish. I believe its a case of letting it go, and once it's let go, it keeps on going. Rust never sleeps no matter where you live.

If it's that bad I would just clean it and let it be. However, I have found in all the amps I have owned, the chrome is much better on the earlier SS amps (like the 2505,2105,Mc30/40,Mc250 or 2100) than the 2205 or the later amps. It seems thinner and somewhat less durable on the 2205/2255, etc.

The worst Mc gear I ever see comes from Hawaii. I don't think I would ever buy anything from there 'cause all I see is rust.

You can't clean away the pitting and you can't clean away the rust, so you are left with doing the best you can - unless you want to tear it down and re-chrome or paint the chassis, which I suspect is a huge amount of work.
 
Isn't it true that dust also leads to rusting?

My 2205 has some minor rust on the chrome. It's not bad, but it's not great. It's probably the most minimal amount allowable, but what can you do? That's the way it was when I received it. I try to dust it every week or so.

Maybe I should add some polish, too?
 
Agreed with CountD, the best solution is preventative maintenance. One thing I might suggest is a pouch of dessicant be placed inside the chassis- assuming this could be done in a manner that wouldn't jeopardize safety.
 
jchouston said:
Isn't it true that dust also leads to rusting?

My 2205 has some minor rust on the chrome. It's not bad, but it's not great. It's probably the most minimal amount allowable, but what can you do? That's the way it was when I received it. I try to dust it every week or so.

Maybe I should add some polish, too?
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Dust itself will not cause rust. You might try using a little amount of naval gel to try to clean up some of the rust tarnish, then metal polish. For that I'd recommend Meguiar's All Metal Polish which does a fantastic job of polishing and protecting chrome.
 
I am much more concerned about the internal corrosion..there was growths on some of the circuit boards contacts. Every switch was intermitant dirty.

I sold a lot of Mac stuff over the years and mostly they have just sat in cabinets and made music. Cosmetics are important to collector types but my biggest concern is service problems... and heading them off.
 
I live about 2 blocks to California's Monterey Bay and the Pacific Ocean. We have fog most every morning and night here - love the lifestyle that creates but it does have the downside of most everything metal being exposed to accelerated corrosion. It can't be helped here - just a fact of life. My ham radio gear and the exposed antenna joints and connections suffer the most.

Even inside a well-constructed, stucco-wrapped house with solidly sealed windows, I take the steps of using waxing compounds intended for automobile surfaces to help keep the oxidation of chrome down to a minimum. The problems really arise when the chrome has already started pitting, though, and there's no real way to stop it once it has begun. In auto restoration, the best way is to cut the rusted/pitted metal out, weld in new. This isn't possible, of course, with our Mac chassis. So, we're left with trying to mitigate the effects that have already started. In a couple of cases, I've just given up, used some auto finish wax and then plan on redoing the surfaces occasionally. It is only putting off the reality of the issue - kicking the can down the road, so to speak.

I do believe that the original pitting may have started with dust sitting on the chassis, then wicking moisture out of the air (in those environments that contribute to it), thereby setting up the pitting process. This would be when the amp was tucked away in a console system much as my MX-110 and MC-225 was for the first 40 years of its life. The MX-100 was installed face-up while the power amp was tucked away down in the bottom of the 10 ft long console with an open back. The difference in the chrome between these two units of the same known age is striking. The MX-110 never had dust settle on the chrome, which is quite solid and looks great. The poor MC-225, on the other hand, has pitted chrome primarily on the face-up, top side where I cleared the rather thick layer of dust from it when I was given the console. Perhaps this scenario can be applied as a controlled experiment in long-term effects of chrome chassis. Further background on these 2 pieces:

- First 15 years spent in Kansas City where it was purchased in 1963 (have the receipt!). High humidity, non-air conditioned home environment.
- Last 25 years spent in Phoenix and Sedona, Arizona - rather arid environment.

So, outside of a full chassis swap, we're kind of stuck with a set of options that range from 'I give up' to 'well, ok, if that's all I can do...'.

Cheers,

David
 
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c_dk said:
I am much more concerned about the internal corrosion..there was growths on some of the circuit boards contacts. Every switch was intermitant dirty.

I sold a lot of Mac stuff over the years and mostly they have just sat in cabinets and made music. Cosmetics are important to collector types but my biggest concern is service problems... and heading them off.
Click to expand...

I'd try putting a small sack of dessicant inside the chassis. Car collectors put them in the interiors and even tie little bags of the stuff to the exhaust system. It's worth a stab so long as it poses no risk to the operation/safety of the unit.
 
Putting desiccant inside a (relatively) sealed enclosure I can see possibly being a benefit, but in a relatively unsealed deal like a ventilated stereo chassis I'm not sure would be a benefit...and possibly a detriment. :scratch2:
 
Well I can't speak for what effects- positive or negative in the case of using it inside component chassis but I've seen it used in interiors and trunks of old cars as well as dangling from the exhaust systems-completely in the open. Also it's often contained in the original packaging of electronics these days. Assuming a given environment is known to be hostile to metal, it's probably unlikely to do more harm than what's being done anyway.
 
I'm sure you have seen that, or maybe it wasn't dessicant (in the cars).

Point being, a bag of dessicant dangling or laying in open space or an unsealed space will soon be doing nothing because it will have absorbed all the moisture it can in short order.
 
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