Hi Carter. Your STV-3H diodes are suppose to compensate for temperature changes. These are to be mounted on the heat sink of TR-13/TR-14, right on the transistors body with a thin layer of thermal grease for better heat transfer. I am not surprised you cannot bias the unit in this configuration, there's simply no, or very insufficient temp/co. On a quick glance the transistors on your F2624 seem to have the correct orientation and so do the EC's. I can't tell about the diodes b/c there's not enough resolution so I include a couple of shots of a tested board for reference. Yes, it's a (very) good idea to test diodes too. Bias related accidents wreak havoc on the driver amp, so test anything you can, but start with resistors and transistors. You may want to trim the excess of the leads of the soldered transistors like Doug mentioned. No reason to leave them that long, they are just an accident waiting to happen. Other than that, I think your issues are related to the bias adjustment and DC offset measurements in conjunction with the lack of temp/co.
Tested F2624 components orientation - for reference:
Suysyy fycgfyygycyycygyycgcgy
A