500B hum

[Ken C.]

If this posting properly belongs somewhere else, please point me to the rules so I learn.

I recently did a recap, IBAM, cathode 10 ohm resister, power thermister restoration. I was delighted with the results. Even the magic eye worked.

Now about a month later, there is a new hum, present in both channels, and fairly loud with volume knob at minimum.

The sound is good - hard to hear through the music with volume up, but it's surely there.

Where should I look for the problem? Do I need an oscilloscope?

Thanks
krcmd1@verizon.net

 

[Tim D]

You came to the right place and help is on the way.

Does the hum change with the volume control? Is it present in all inputs? Aux, Phono, etc?

Have you checked the voltages in the power supply to ensure they are as expected? A failed cap or failing rectifier could cause hum.

Better experts will be along with more and better suggestions.

 

[adnick]

Also make sure your RCAs are connected well, they can certainly induce a hum, have to move mine around a bit on occasion.

Some really great guys here that share their knowledge….

Welcome to the site,

Andy

 

[Ken C.]

Thank you! input cable to aux was disconnected from source. I think problem solved! will leave it on again for a bit and see if it comes back.

 

[adnick]

No problem, glad it was something simple, that’s all I’m good at


VR
Andy