Image doesn't need high res here, just to show that the inverters at the bottom of the image are ones which have now been removed. Which saves a chip!
A second inverter chip was mostly used in the reset circuit, this is now a normal open collector buffer. This saved some gates also. But I needed couple of inverters anyway for two other parts of the circuit..
Firstly the HDRQ was a LS04, that chip is no longer there, but I had a spare LS07 inverter, so this is been swapped, because it is open collector now it had to have a pull-up.. No big deal..
There was a LS02 used as a inverter on the keyboard drive light circuit, this has now been moved over to the YM circuit, which just so happened to have a gate the same chip anyway... So routing will be a lot neater around that now.
So basically the inverters in the Midi circuit have been replaced by a buffer. The keyboard drive light has had two gates removed (double inverters again basically) and replaced by a single buffer. The two inverters on the HSYNC signal have been removed, they simply wasn't even used in this design (was used for the modulator originally).
This all may sound catastrophic, but was actually pretty simple.. Basically I have just moved some double inverters in place of the single buffer , so basically saves a chip...
Related information and WIP etc
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