2. amps-preamps
  3. 165850-46419

Conrad-Johnson Discolored (rusty?) Allen screws on side of MF-2550.

I just bought a used CJ MF-2550 a short time ago and it's been working perfectly. Today I was just checking the routing of my cables with a flashlight and I accidentally noticed that there are Allen (hex) screws on either side of the amp, between the cooling fins. There are also regular Philips screws. The question is that the Philips screws all look completely normal, but some of the Allen screws are discolored and may be rusty.

Would you think I should just leave well enough alone since the amp is working OK or should the discolored Allen screws be replaced? I'd be hesitant to do the replacement myself, in case any of them broke off and left inner components unsupported. Any advice would be appreciated. A link to a photo I just took follows.

https://i.imgur.com/rJnfyZs.jpg
rff000
pehare's avatar
pehare
831 posts
 
For years I've use Ospho/phosporic acid all the time to neutralize rust on parts.  It won't harm surrounding finish and gets rid of the rust.  It doesn't burn your skin like you think it might.  I use a q-tip and dip it in the bottle then lightly dab on rusted bolts, screws and parts.  

https://www.acehardware.com/departments/home-and-decor/cleaning-and-disinfectants/rust-removers/1386...
corelli
950 posts
 
Had the same thing of a Bellari phono amp. 
Remove the screws.
Clean as above
Shove the threaded end into styrofoam and spray paint heads of the allen screws.  Make sure to let the paint harden for a week or so before replacing them.
pehare's avatar
pehare
831 posts
 
corelli, great tip on the use of styrofoam thanks!
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