I have rebuilt the re-150,201, and 301 ... most of the problem is
from worn tape heads and they can be replaced.. but regarding the
pinch roller. they wear down unevenly and end up perpendicularly
"untrue" to the tape so they are pulling one edge of the tape through faster.
the other things that happen is that the motor starts wearing and may need to be rebuilt or replaced.. dont want to scare you.
the first thing on any of these space echos to do is use deoxit on all the
wiring harness clips and in the motor. Then you need to use Denatured
alcohol mixed down with distilled water on all the rollers, heads and pinch roller. They say not to do that to the pinch roller because it can harden it..but thats on new things.. these are old and the rubber is already hardening.. just be sure NOT to use rubbing alcohol AT ALL.
Denatured Alcohol is sold at home Depot in the paint department. The
guys that work there will say they dont carry it BUT THEY do and its right next to the acetone and thinners.
finally and sometimes most important. These units have some decent size electrolytic caps.. and Old caps drift terribly.. they supposedly only have a shelf life of 15yrs.. Doing the math, you KNOW your unit needs to have a cap job. Some may argue and say that this is not a tube amp and the rules dont apply but in the hi fi world of analog.. fresh quality capacitors mean everything. They dont have to be super expensive but
they need to AT LEAST be Xicon or Nichicon, at worst Illinois.. the stock stuff in them is pretty junky.
Oh ya... when was the last time you carefully demagnitized the tape heads? That has to happen at least 2 times a year.
..okay I'll shut up.
ps. do you need the service manual?