The 240 Compressor, PS PUMP, and Alternator all have a 10mm hex head adjustor bolt.

They also have locking bolts/nuts (13mm hex) that keep the adjustment "locked".

The Compressor has 2 locking bolts. The rear one is hard to see or access. But it can be done with clever contortions and combinations of extensions, wobble sockets, etc. I'd advise removing the AMM and airbox cover, and using 3/8" drive tools for a tad more access to the rear locker, which is directly aft of the front one.

The PS pump also has 2 lockers which can be reached with an open or boxend wrench.

The alternator has 1 lock nut on a "stovebolt" comes thru the rear of the adjuster block that the 10mm adjuster bolt is threaded into and thru. The nut is on the front, partly hidden by the belts, and easy to access with ratchet and socket.

The Alternator pivot bolt at the very bottom may or may not be locked down tight, making adjustment difficult. The bolt head is at the front, and may be either 12mm or 13mm. The nut at the rear is 13mm.
Before reaching down in back with a 13mm wrench, be sure to disconnect the battery negative cable. Once it's safe, hold the nut (by feel) and loosen the bolt head with socket and ratchet.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.