METHOD:
1. paste RTF content to InputRTF TEXTAREA,
2. press "Convert" button,
3. get RTF from OutputRTF TEXTAREA.

replace "fonttbl" RTF tag.

Input RTF:
{\rtf1\mac \deff387\deflang1033 {\fonttbl{\f38\fnil\fcharset77\fprq2 \'8bé0\'f2é8éd\'f1éaé8é9;} {\f387\fnil\fcharset77\fprq2 \'8f\'f0\'dfécéeé9 \'8f\'f0éeéf;}} {\*\pnseclvl8\pnlcltr\pnstart1\pnindent720\pnhang{\pntxtb (}{\pntxta )}} {\*\pnseclvl9\pnlcrm\pnstart1\pnindent720\pnhang{\pntxtb (}{\pntxta )}} \pard\plain \qc\fi720\nowidctlpar \f387 {\b\f38 Beg of test RTF - \'81é0é7é0 \'84é0édéd\'fb\'f5. \par }\pard \qj\fi720\nowidctlpar {\f38 \par 1. \'88\'f1\'f2ée\'f0é8\'df \'90ée\'f1\'f1é8é9\'f1éaéeé3ée é3ée\'f1\'f3é4é0\'f0\'f1\'f2é2é0. \par \par 2. \'8c\'f3éb\'fc\'f2 é8écé5é4é8é9éd\'fbé5 éf\'f0éeé3\'f0é0écéc\'fb \par \par End of test RTF in MacCyrillic encoding with strange fonts. \par }}

Output RTF:
still void taOut - out RTF
Output HTML - non-ASCII text in UniCode (for test purposes):
still void taOu2 - HTML source

<noscript></html>