The IBM PCjr was released in March 1984 and discontinued in 1985. The PCjr uses the Intel 8088 processor at 4.77MHz.
Noisy Disk Drive
Silencing the noisy PCjr disk drive is as easy as lubricating two rods inside your computer. The drive head carriage hangs on two rods and sometimes hangs up, causing the noise. The rods are lubricated with Silicone grease or Teflon oil. Radio Shack sells the Teflon oil as "Pecision Oiler". Machine oil (3-in-One) is ok, but may cause some corrosion and generally won't last as long. One final caution- Don't touch or get any lubricant on the drive heads themselves.