Little 6BQ5 am squealing....HELP

[djn]

Man, I've burned my share of thin sheet steel. Thanks PRR.

 

[pcan]

The driver tube pins or socket contacts may be dirty. This issue is pretty common on old radios with 9 pin miniature sockets. If the tube pins does not make good contacts with the socket, you may hear noises or even start a motorboat oscillation by moving slightly the tube while the amp is working. Grab the tube at the tip to avoid burning the fingers, and be prepared to cut the power if the amp begins to oscillate badly.

 

[djn]

I can clean the pins easily but how do I clean the sockets?

 

[rmyauck]

Welding torch tip cleaning wires, but be gentle as you don't want to wear away too much metal. You can tighten loose ones with picks etc.

 

[pcan]

I can clean the pins easily but how do I clean the sockets?

When the Deoxit spray is not enough, I use a precision needle file. The file tip is 1mm in diameter, but I have to be very careful not to break the file or to bend the contacts out of shape. Sometimes the socket is oxidized beyond repair, this happens mostly on the brown or black sockets. White ceramic sockets are usually OK.

 

[djn]

Thanks guys. I still have a full set of tip cleaners. I'll give those a try.