Can I use a 512K EPROM as a replacement for a 128K one?

[Midphase]

Howdy everyone,

Just got me a XGecu T48 burner so I'm having some fun updating some of my vintage synth firmwares.

I pulled a HITACHI HN4827128G-25 from my Korg DW-8000 and rather than erasing it, I was thinking of burning the latest firmware on a AT27C512R-45PU that I have handy and which has the same footprint.

Any thoughts? Good idea? Bad idea?

Unfortunately the 128K are difficult to find and kinda expensive, and since I already used the 512K to replace a 256K EPROM (I didn't actually realize I did that until I did and it's working just fine), I was wondering if I can do the same thing with the 128k?

Many thanks for any info that you might be able to provide, as well as any settings I would need to use in the XGecu Pro app.

[wraper]

If you connect A14, A15 pins to GND, I see no reason why it would not work.

[edavid]

If you connect A14, A15 pins to GND, I see no reason why it would not work.

Or you can just burn 4 copies of the data, then it doesn't matter what A14 and A15 are tied to.

[wraper]

If you connect A14, A15 pins to GND, I see no reason why it would not work.

Or you can just burn 4 copies of the data, then it doesn't matter what A14 and A15 are tied to.

Yes, hewever they should not be left floating in any case. Connecting them to 5V is fine too as long as you multiply the data. If they're already connected to either, then no hardware modification is needed.

[pqass]

A 27128 socket would normally have both PGM (pin 27) and VPP (pin 1) tied to Vcc. A 27512 replaces these pins with A14 and A15, respectively.  Therefore, putting a 27512 into a 27128 socket will need a copy of the 27128 data on the top quarter of the 27512 (C000-FFFF).

FYI:  Your reference to "128K", "256K" and "512K" EPROMs are actually only 16K, 32K, and 64K, respectively. 
         K = 27xxx where xxx/8

[Midphase]

Thank you all.

I was reading about copying the data to fit the larger EPROM, and then lo and behold somebody already did that and was kind enough to share the .bin file. I was able to use that to burn the new firmware into the synth and I was happy to see that it is indeed working well.

Many thanks, I am sure I will have more questions soon as I continue to update the rest of my synths.