Why Does This Kenwood Keep Lighting Up My DBT?

Need tools? Here's a video showing what I use (with links!): https://youtu.be/MLK649c1_fM The Kenwood KR-5010 is a late 70s stereo receiver that happens to use STK-0050 darlington power packs for the power amplifier section. Link to STK-0050 with discrete components: https://audiokarma.org/forums/index.php?threads/stk-0050-replacement-for-sx-780-and-others.721181/