Hello!
The 388's an exceptional unit, and is all that much better of a score if you can get it nearly- or actually "free". Ebay average on the nicer, well-kept 388's is about $495, give-or-take, & depending on the day.
I'd not venture a guess as to what the "horrendous noise" was, but it would serve you well to find a brand new reel of tape for testing. Make sure you clean the tape path, as many older tapes may leave a thick sludge on the heads and all tape path guides. Any heavy grunge on the heads may cause the noise you're talking about.
The 388 is a fine unit for homers, as it was originally aimed at the small "post-production", "jingle" studio, or "sound-for-film" applications. These days it's just a "bloated" Portastudio, if you ask the average person. Heh, heh.
If you're in the Los Angeles area, I'd check it out for free, & do minor repairs and calibration for nearly-free,... if ur in my area then check me out.
In summary, no matter what condition the 388 is in, I'd try to score it cheap! I've heard of people giving their 388's away to other eager users, just because they've either not recorded in some time, or maybe they've moved onto another recording system. Anyway, the 388 is keen,... cheap is good & free is better!! So, get it now & worry about fixing it later!
What was the question? Heh.