• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

McIntosh MC275 IV: Old leak from right transformer

K

kj510

New Member
I found a black liquid like oil at the right transformer of my MC275 IV today.
It is found on the chassis of the right transformer and leaking from between bottom of the transformer and the chassis. I wiped with tissue and it was black. And it is leaking from right side (power cable side) and front side (tube side).

Can any body know what is happening to my MC275? Do you think it is serious and need maintenance? Any comment is highly appreciated.
 
Register to hide this ad
First, don't use it until it's been checked for bad driver/output tube(s), leaky capacitors, drifted resistors, and proper bias voltages. It's always possible that a bad output tube may have previously stressed the transformer and overheated it, not uncommon with old tube amps.
Depending on the vintage most if not all of these old tube amps will need a renovation starting with the power and bias supply and on thru the signal board capacitors and resistors. Certain resistors must be matched and well within tolerance for proper operation. Tube quality should be verified.
 
Last edited:
Looks like he is referring to a MC275 mark IV. Something got hot to get it to leak. I have a mark IV also.
 
rcarlton said:
Looks like he is referring to a MC275 mark IV. Something got hot to get it to leak. I have a mark IV also.
Click to expand...
So, if this would be a later version I'd suspect tube problems first. The outputs are the most highly stressed and therefore most prone to failure tho' the DC-coupled driver tubes could cause mischief.
 
kj510 said:
I found a black liquid like oil at the right transformer of my MC275 IV today.
It is found on the chassis of the right transformer and leaking from between bottom of the transformer and the chassis. I wiped with tissue and it was black. And it is leaking from right side (power cable side) and front side (tube side).

Can any body know what is happening to my MC275? Do you think it is serious and need maintenance? Any comment is highly appreciated.
Click to expand...

Hello !

I don't really understand about which transformer you are talking about ...
Can't you post a picture of it ?
I can tell you that this is not the same "story" if we are talking about power transformer or output transformer .
I hope for you that this is the first case , if it is not this is not a good news !
In more than 35 years on MCINTOSH units I never saw any output transformer leaking like you describe it ...:no:
 
It's power transformer

Thank you all for your replies. It is the Power Transformer behind V11. Just realized yesterday. 2 Output transformers are fine. Also the power transformer was not hot when I fond leaking yesterday. It was touchable temp like hot shower. I try to attach photos.
 

Attachments

  • IMG_0659.jpg
    IMG_0659.jpg
    57.3 KB · Views: 114
  • IMG_0661.jpg
    IMG_0661.jpg
    53.3 KB · Views: 107
Last edited:
I dunno, it would have to get pretty freakin' hot to melt the tar around the transformer. The tar is molten in a cauldron at the factory and when it goes in it dries really hard and it would have to really get cooking on the amp enough to ooze. I have had transformers get really hot on MX110s, Mc250s, Mc40s, and other stuff that had issues and the tar wasn't close to liquifying. I suspect it might be some run-off from something else like maybe on the wires, etc. I doubt it's a serious problem unless it keeps coming out.
 
Hi CountD,

Thank you for your reply. As you say, it is like tar. Today is a national holiday in Japan so I will call a distributer in Japan and ask. I will keep updated as it might be useful for MC275 users in the future.
 
Definitely get in touch with your local distributor but also send a copy to McIntosh, too. I'm sure they will be able to provide ways to figure out what is happening.

Cheers,

David
 
Hi David,

Thanks for your advice, I actually sent a message thru McIntosh Web site and it said I should get reply within 72 hours. Sound is good and power transformer is not hot so I really wonder about the black tar leak....
 
That will clean up with Naphtha lighter fluid on a paper towel, keep in mind it's highly inflammable nature.
 
Hi All,

I had a reply from a distributor in Japan and they said it is not problem, electrically ok too. It sometimes leaks as they say. Just clean with alcohol cotton. If it leaks a lot in the future they advised to contact again. So Pio1980's advice was just the same as theirs! Thank you! Koji
 
kj510 said:
Hi All,

I had a reply from a distributor in Japan and they said it is not problem, electrically ok too. It sometimes leaks as they say. Just clean with alcohol cotton. If it leaks a lot in the future they advised to contact again. So Pio1980's advice was just the same as theirs! Thank you! Koji
Click to expand...

Did you get the response from McIntosh, the one you sent through their website? Thanks
 
Hi arien, I had a very short response from McIntosh just "it should immediately go for service". But I also did not explain the situation to them very well as English is not my own language. I explained my situation in Japanese in detail to the distributer in Japan as they explained what is happening and next step to contact them again. They say it can happen rarely and the amount of tar is little for my case and it is not serious for power transformer.

Not sure if it was output transformer. But my output transformer is cool, cooler than power transformer.
 
kj510 said:
Hi arien, I had a very short response from McIntosh just "it should immediately go for service". But I also did not explain the situation to them very well as English is not my own language. I explained my situation in Japanese in detail to the distributer in Japan as they explained what is happening and next step to contact them again. They say it can happen rarely and the amount of tar is little for my case and it is not serious for power transformer.

Not sure if it was output transformer. But my output transformer is cool, cooler than power transformer.
Click to expand...

Hi kj510, I truly believe that it needs to be looked at by a qualified McIntosh technician..well, if that happens to my mc275, that is what I would do..it is definitely not normal to have transformer leak...
 
You must log in or register to reply here.
Back
Top Bottom