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

Showing 4 responses by rff000

rff000 OP
23 posts
 
Thanks for your help.
rff000 OP
23 posts
 
Speakers are NHT 2.5
Preamp is McCormack Micro Line Drive
DAC is Jolida FX Glass DAC III
CD Player is Rega Planet
Turntable is Thorens TD-203
Phono Stage is Rotel RQ-970BX
DVD and Hi-Res: Sony UBP-X700

Not real high end, but I used the system for many years with a smaller amp than I just got. I’m a little reluctant to spend a lot for a factory check when everything is working well but I may ask them how to handle the rusty screws.
rff000 OP
23 posts
 
I'd be inclined to just get a bunch of rustproof screws and replace them but I want to first find out if they have to be a specific kind of metal and what they are fastened to. I'd hate to mess up the job of re-fastening new screws to components inside the amp since it's working fine now.

I also noticed something strange. At the exact same position on both right and left sides (the fifteenth cooling fin), there is an empty screw hole with threads showing. Since it's at the same position on both sides, it doesn't look like an accident. Maybe the case has the threads but they're not used for this amp design.

I hope I can get an answer from the company without having to bring it there for service.
rff000 OP
23 posts
 
Thanks. I'll check it out.
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