I think I might have found a clue, that Bruce has already eluded to, above:
If IRQ 10 is not reserved for ISA/Legacy in the BIOS, then MIDI communication doesn't happen with the HDR.
In sorta "vintage" PC computers, IRQ 10 is an important kind of "permission level" to "interrupt" the main processor of the computer, to handle a task coming from IRQ 10 via an "ISA" type of card slot on the motherboard (IRQ9 is another one, commonly available to "Media Controllers" in vintage PCs... but doesn't play a role in the HDR/D8B, I think).
So, the MIDI board (a card that fits into such a "ISA-slot" on the motherboard inside the PC part of the rack unit) that lives inside the HDR, needs permission to use IRQ 10 in order to be able to "interrupt" (IRQ=Interrupt Request) the processor inside the PC part what's inside the HDR. If it doesn't have that, MIDI communication doesn't happen... so, no sync between the D8B and HDR.
The way I found out was, that my HDR was down until recently... finally managed to get in the BIOS (bad contact at the KVM) and set everything to how it should be, then posted what I wrote further above.
Today, I wanted to boot the system again, just to see if it still works... and that battery is dead, and the settings are gone... and if I try to skip the BIOS settings by pressing "F1 to continue", despite all the correct settings, elsewhere, the transport control doesn't move and the Play/Stop etc., buttons don't work.
So, next thing I tried, was to ONLY reserve IRQ 10 in the BIOS for ISA/Legacy and not even put the rest of the BIOS settings the way they're supposed to be (well... I turned off the Parallel port since that's not used, but otherwise, didn't follow instructions)... and on the next boot... my transport controles and time display on the D8B worked again, and showed the same stuff as on the HDR.
I guess I really have to replace that battery in the HDR AGAIN, already...
...also, because I talked about clock termination further above, a lot. For everyone reading along, I'm attaching what you need if you were to just REMOVE termination entirely, from the Apogee Clock card and NOT install a switch... you could then use a BNC T-Piece to attach a 75 Ohm Terminator on one end of the T-Piece, and have the BNC cable go down the chain to your other devices that should receive and/or pass through a word clock signal via a dedicated word clock BNC connection.
Arnie75!
(Nobody calls it that, haha... sorry!)
![HDR_D8B_Time_Arnie75 2.jpg](./download/file.php?id=907&sid=386686afd9845c630238dd053729b3c7)
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