Very good points.? I never would have even considered the available current/watts.? I should say, I'm a TOTAL amateur with this stuff.? Seriously.? I find all of this very fascinating but I know next to nothing as far as electrical theory goes.
With that said...If Pin 7 can only deliver 4.84 mA, that will be a problem.? At 5V with the 82 ohm resistor in place, the frontlight draws 24mA. ?
Fortunately, the service manual is readily available.? Just looking over the block diagram on page 9, I can see at least one promising option.? Right after the 9V input, there is IC33 which delivers +5DC.? It's the giant transformer on the main board.? The part number is SI-8501L.?? That probably supplies the MIDI out and whatever else needs 5V. Looking at the datasheet, I found the output pin and I just measured it on the QY100.? It's right at 5V.? I have no idea how to determine if an extra 24mA will be a problem for this thing.? No clue.? Also, there is IC24 which feeds the contrast knob.? It says it converts from +5 to -10.? Maybe I could connect to the input which I'm guessing is fed by IC33.? ?
Is there any reason not to connect the frontlight directly to the output of IC33?? There couldn't be an easier spot to solder onto.? Fairly big pin with not much around it.
Too bad it'll take a couple weeks to get replacement kits, I'm chomping at the bit to get this done.
