Buy a cheap (e.g., JP1 programmable or a used RCA RCRP05B). These have an IR receiver on top. Point your original (or borrowed) AVR 142 remote at it, press a button, and it “learns” the signal.
Check eBay for a “for parts” AVR 142 that includes the remote, then keep the remote and resell the receiver. Failing that, buy a used Logitech Harmony 650 — it’s actually better than the original. harman kardon avr 142 remote control
This is the gold standard if you want 100% functionality without hunting for the exact OEM part. Believe it or not, you can control your AVR 142 with a smartphone — if your phone has an IR blaster (rare now). Older Android phones like the Samsung Galaxy S5, S6, or Xiaomi models have this. Buy a cheap (e