problems w/clicking (popping) noise

[Esquire]

I'm using an ancient Porta 7 to do some music mixes. Yesterday, a loud clicking sound started occuring in random intervals. It sounds like the pop heard when an amp is turned off w/o the gains being pulled down. Do I need to clean the heads? Something else? Or is it just a part of low-end tape-based recording. I bought the 4-track about 6 years ago and have not used it that much. My last heavy use was about 4 years ago and I did notice the same sound but only a couple of times w/in the span of an hour. The sound did not reoccur until yesterday, but w/greater frequency. Any advice is greatly appreciated!

[mnicoletti]

Sorry, I don't know about this particular unit, but when units start clicking or popping, the power supply may be involved...best to have it looked at...

Mike