Stax, 30 29 bytes

£└≤☻╘pÿ╖╡A[ô%æτ⌐}►ºôßHl4⌡π%^ 

Run and debug it

Port of my Stax answer in Balanced Ternary Converter.

Explanation

Uses the unpacked version to explain.

139$VA+cz{;3%+,^3/~;wY1|I@'|ay2|I@L
139$VA+c                               "139AB...Z", make a copy
        z                              Empty array to store the digits
          {         w                  Do the following until 0.
           ;3%+                           Append `b%3` to the digits
                                          Originally, `b` is the input
              ,^3/                        `b=(b+1)/3`
                  ~;                       Make a copy of `b` which is used as the condition for the loop

                     Y                 Save array of digits in `y` for later use
                      1|I              Find index of 1's
                         @             Find the characters in "139AB...Z" corresponding to those indices
                          '|           A bar
                            ay2|I@     Do the same for 2's
                                  L    Join the two strings and the bar and implicit output