Marantz 2285 "impossible stains on faceplate"

LuisNiels

New Member
Hello everyone
I just found a very good deal on a Marantz 2285, i couldn't pass on it even tho it's in bad shape,
my main question is about the "impossible stains on faceplate" i've tryed the usual stuff
like dish soap scrubbing, alcohol, acetone, degreaser, circuit cleaner, tooth brush, i even tried using a tooth pick to scratch the stains with all mentioned cleaners and didn't worked.. nothing seems to work, i've never
had problems with this kind of stains

i'll include a few pictures, can someone identify these impossible stains and what can i do about it?

thank you and please forgive my bad english :)

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other pending issues:

impossible stains on faceplate...pending
bent back corner (looks like it was dropped)...fixed
2 bent faceplate corners...fixed
missing AM antenna...pending
missing balance slider knob...pending
missing 4 faceplate screws...just bought them on ebay
loud buzz on both speakers...(probably PS issue) pending
needs all ilumination upgrade... pending
needs removal of 40 year old dust...pending


after finishing all of the above, maybe i'll do a full recap

i hope to bring this beauty back to life :) wish me luck
 
Those stains look like they may have been caused by something corrosive. If so, probably won't come off.
A good cleaner wax like Meguiars may help or Blue Magic Metal Polish also may help.
 
The "stains" in question really look as if something corrosive (caustic or acidic) has actually etched the anodizing of the aluminum. Anything abrasive like magic eraser or scotch-brite could end up leaving a bright spot that will stand out more than the stain.
Proceed with caution.
 
If its something that etched the surface, you could try some treatment that could fill that in w/o permanent effect: a dab of Armor All, or even a bit of vaseline, or a touch of silicone lube, or furniture wax.
 
I bought a Marantz 2230 with a badly stained faceplate I tried my go to 409 with a soft toothbrush with no success I tried wd-40 and it worked like a charm just be careful around the lettering. Caution all stains are different but wd worked for this particular piece.
 
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Thank you all for the ideas... i ended up doing what plaittwice recommended, since a had a scotch bright on hand (the black one.. not green) and it did worked, but like tarior said it left a few bright spots, the good thing is that they are less noticeable than the stains... i took the gamble and i feel that ended better this way, let me show you the results...

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next, between "tone mode" and "bass" is a barely noticeable bright spot, and under bass too

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Thank you All again!!
 
For anyone else having this issue, there is a polish made called Flitz. It is intended for stainless steel grills. It works wonders on cleaning many stains off metal/glass. I've even used it with some luck on old paint to bring a bit of shine back. Granted this was on a project 1960 Chevy Impala. Maybe a little different. But should work well for stains on the brushed surfaces.
 
Just a thought for the future.

Thinking about the stains again. I assume that in general these brushed aluminum faceplates are coated with a light clear lacquer. Otherwise they would discolor to aluminum grey. A lacquer coat keeps them shiny. I think those sorts of stains above are really the lacquer getting eroded by something. Not the aluminum itself. If that's the case, it might be worth trying a little, very little, lacquer thinner _just on the spots_. Lacquer thinner will certainly remove any printing on the faceplate. But a bare touch of it could redissolve the cloudy finish and allow it to reevaporate and clear.

The advantage to this is that if it works, it would not physically alter the brush pattern on the aluminum at all.
 
Yeah, that makes sense. Certainly on high end stuff. But I have detailed, yet suspiciously vague, memories of seeing lacquer worn through around power buttons.
 
Yeah, that makes sense. Certainly on high end stuff. But I have detailed, yet suspiciously vague, memories of seeing lacquer worn through around power buttons.

Not sure how it is vague? I'd also bet that they are clear anodized and not lacquered. The lacquer that you saw worn through was pretty likely dirt from repeated use. It is also somewhat possible that the anodizing was worn, it is after all a coating that is only a couple mils thick at best.
 
Anodizing is hard, much harder than aluminum (think aluminum oxide, or sappire).

I'm not sure that the older Marantz faceplates are anodized. I have looked closely at the '74 faceplates (2235, 2325) that I have and believe that they are just brushed aluminum. The later ones I have / had (2220B, 2238, 2252, 2285) have an inset panel with the pushbuttons that is brighter and appears clear anodized, where the main faceplate appears to be natural/brushed.

Depending on the alloy, the aluminum might or might not oxidize and brightness can vary. A pure aluminum will polish extremely well and the main faceplate seems to be quite bright and soft, where the inset panels look to be a stiffer alloy (more zinc) which probably would corrode quickly if not protected by the anodizing.

As mentioned above, be very careful with the cleaners, caustic cleaners will quickly stain the anodized aluminum white, and it can not be removed without removing the anodizing (which will not go well, it'll be quite obvious).

Looking at the OP's stains -> bright spots, it is probably just a matter of creating the original texture again with the right grit-count emery cloth, ... best tried on a piece of scrap. As you polish you will be removing the original texture, polishing down the high-points, and the only way to restore it is by re-creating the texture with something like emery cloth.
 
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