MC-30 Hum/ hum level pot no effect

[AudioWizard]

Here are some internal pictures;

 

[AudioWizard]

Here is some more, if you need more let me know.

 

[cspyon]

Did you solve the hum issue? One of my MC30 had hum issue, too. When powered on, the hum was briefly there and then disappeared within several seconds.

 

[AudioWizard]

Update, Yes found the problem thanks to fellow AK member Ajauwen eagle eyes, C3 was one eyelet off on the top of the vertical board. The hum was there before I recapped it, so the cap was in the wrong spot from the get go. I did take pictures before the recap so I just put it back as it was before. I also soldered the output sockets to the chassis, so not to rely on the rivets for ground. I also helped lower the hum as seen on the scope. Just a heads up to help people, the hum control has very little effect on the hum, just a little bit of variation on the scope, although swapping in another signal tubes does change the amount of variation.

So a guess the moral of this recap is, don't trust that the previous work done on a unit is right after 60 years worth of repairs.

Thanks again to Ajauwen for spotting the cap placement error!