Gibson Skylark Grouding Questions

[msmith1]

Gibson Sklark Grouding Questions

I just inherited a "vintage" Gibson Skylark GA5T Amp. It sounds pretty good but there is a definite hum and ... (this is the bad thing) when it is swithed off the metal and my guitar go hot! its a low voltage but definitly a tingle! Attached is a link to the schematics. I want to ground the chassis and I am checking for shorts. I probably need to install new isolated input jacks. What else do I need to watch for or is there a good reference. This is my first "project' amp. I am new at this so keep it simple, please. Thanks.http://www.harpamps.com/gibson/pg_0089.jpg

 

[Giaime]

It's easy that the 0.02uF capacitor in the primary of the power transformer is leaky or shorted. Remove it, it's not needed, and replace the power cord with an earthed one, 3-prong.

While you're here change all other capacitors.

 

[amperex]

Gibson amp

Although no leakage issues of line voltage, a new 3-prong cord replacing the stock two prong power cord removed all audio hum on our Gibson Hawk.