I still had a pair of non-working Analog boards (early ones) the design is slightly different from the late ones.   https://68kmla.org/forums/index.php?/topic/31279-dp4-on-classic-ii-analog-board/   https://68kmla.org/forums/index.php?/topic/31245-low-voltage-classic/   Both of them were not working at all (no outputs from the secondary side where new caps have been replaced )   These boards have a Zener Diode (18V) on location DP1 (just above the TDA 4605, location IP1 in the picture be