The fuse (F1) on the comm board inside the HDR that Jondav referenced above measures 0 ohms (as expected) so that ensures the +12VDC didn't blow out anything here. I think the Optoisolator (U1) isn't part of the equation (
at face value) at initial triage, the voltages need to be ensured they're being passed to the remote just to get things to '
light up' (
d'uh)...
That being said, I'm having a look at the mini 'choke' type inductor that's the last component directly inline with the RJ45 jack used to connect to the Remote 24:
MIDI-IN : 1 In -> 8 Out (to J1)
MIDI-OUT : 2 In -> 7 Out (to J1)
GRD : 3 In -> 6 Out (to J1)
GRD : 4 In -> 5 Out (to J1)
MIDI-IN : 16 In -> 9 Out (to J1)
+5VDC : 15 In -> 10 Out (to J1)
+12VDC : 14 In -> 11 Out (to J1)
+12VDC : 13 In -> 12 Out (to J1)
There appears to be a '
floating' ground reference for the MIDI out signal connected to the mini Inductor (L8) pin 2 input side - not important in this scenario, just point this out for any future reference or keyword search of the forum. So, concentrating on the voltages going down the wire from this point to the remote via CAT5. It's weird in a sense, because +12VDC is kind of a 'hot' voltage to be passing thru standard ethernet cables, but I'm not gonna concentrate on that right now due to there isn't any apparent visual damage to anything. SO, I'm gonna have to fire this thing up and see if I get the proper voltages to the jack, because if memory serves (
I was doing a lot yesterday) I quickly took voltage measurements at the remote end of the CAT5 cable and there wasn't much happening. Can't remember if I saw +5VDC or not, but I
specifically recall not seeing anything even close to +12VDC...
Once I can determine if the voltages are apparently getting all borked up - HDR comm board or Remote 24 - it will the become pretty apparent as to where I gotta begin to actually getting things repaired/replaced and back to my '
standard version of reality'...
Stay tuned - busy day ahead...