Old block logo MXR Dist+ getting bad RF interference

[JCM1959]

My main distortion pedal is an early Block logo Distortion+.  Lately I have been getting some fairly bad RF interference.  I have tried moving the board closer to the back plate and have made sure all the wires are good to go(not crossing etc.., broken inside the shielding), but cannot seem to stop the interference.  Can anyone pass along some tips on how to kill it?  A friend who works at a vintage gear shop said the IC might be on its way out.  I would like to keep the pedal as stock looking as possible and it is one of the old pedals that uses a board where the componants are using solder traces inbetween eachother.

[Dai H.]

not sure how you can fix it, but have you tried cleaning the jack contacts (esp. the ground)? Seems to sometmes contribute to RF if the ground connection is not good. At least that is easy to try.

[brett]

Hi.
Op-amps are usually 100% go or 100% whoa. 
Try putting a small cap between the output of the op-amp IC and the -ve input.  Between 10 and 47pF will do it.  But not too big or the top end will be affected.
Look at the Tubescreamer schematic as an example.
cheers