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What’s wrong with these McIntosh Monoblocks?

Evening, got a question about these two McIntosh MC40 amplifiers. I got them from garage type environment, humidity was present as they have some surface rust, but absolutely no damage or dents. Opened them up and did a visual inspection, nothing looks burnt out or bad. However, I replaced the fuses as they were both burnt out with ones that were identical, ensured the voltage setting was correct, plugged the amps in(no speakers connected), and nothing. Removed the fuses to find them both burnt out again. What could be causing this? Would be eternally grateful to anyone who can help.

polak
asvjerry's avatar
asvjerry
4,618 posts
 

As Clint said..."Are you feeling lucky?"

Good luck. 🤞👍

bigkidz
3,382 posts
 

@aball - correctamundo - I am in New Jersey if you need repair assistance.

 

Happy Listening.

elliottbnewcombjr
5,386 posts
 

problem now is the same as what blew the fuses in the 1st place. unusual that both amps fuses were blown, and both blew again.

fuse specs: perhaps someone put the wrong fuse in them. find the fuse specs, get a couple pairs of them, see what happens

how rusty, i.e. if they need work, fix spend money, could you re-sell them for a profit?

polak OP
2 posts
 

Not that rusty, just a really light layer. I would definitely have to refinish the pieces though. Checked the fuse and the correct one has been used, 1.5A sloblo. 

erik_squires
16,060 posts
 

Hi OP:

Variacs are used to gently turn amplifiers on, letting you turn the power off before really major damage/fire has occurred. Technicians use them both for recently repaired gear as well as for amps like the one’s you are describing, which may have been stored for a long time and or improperly.

At the very least, letting a piece of gear like that dry out for a couple of days inside before turning them on is a good idea too.

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