Just purchased jlg80f with 6 cyl. Ford engine. Everything works fine but the boom. Guy I got it from thought maybe solenoid was stuck.
Welcome to the Forum! There are a few things that need to happen for the 80F to telescope. The main thing - if it has outriggers, they must be extended & raised and all the outrigger switches must be functioning. If it has extendable axles, again they must be extended and all the switches functioning. All those switches run through a set of slip rings & brushes located under a cover above the hydraulic swivel (center of turntable). Those slip rings/brushes can give trouble too. That whole safety circuit must be functioning before telescope will work.
Outriggers are out and down, boom goes up and down, rotates, platform levels and swivels boom does not go in or out
9 time out of 10 when the telescope on an 80F quits working, the problem is a broken wire at one of the micro switches on the outriggers or at the electrical swivel. Have you confirmed that your telescope controller has output? In the basket panel, and in the main panel, terminal #2 and #3 are the telescope. (wire color is #2 white, #3 red) With a volt meter hooked to those terminals you should see 6 volts and up moving the controller one way, 6 volts & down moving the controller the other direction.