I also own a 1980 Series 1 guitar (and bass), and a FAG-170 (and FAB-170). Jon, I had similar questions as you, because one of the pickups in the FAG-170 was dead when I received it, and the FAB-170 needed some minor circuit repairs. So I've done quite a bit of research on the Fernandes FAB/FAG instruments, just to restore them!
As a thought experiment - Yes, theoretically you could do this, but I agree with others here that it might not be cost-effective.
- In terms of shape/dimensions and many of the components, it's functionally identical in many ways. E.g. the XLR cable's pin assignments are exactly the same.
- To answer your question about the power supplies: Yes, you can use a Fernandes power supply with Alembic electronics. BUT I would recommend NOT to use an Alembic power supply with a Fernandes instrument, because the opamps in the FAG-170 have a slightly lower maximum +/- voltage than Alembic's, and Alembic's power supply does slightly exceed it. The voltage difference is not 2x the voltage, but it's still slightly more.
BUT:
- Getting a full set of Series electronics is difficult, in the first place. I may have seen someone sell a set maybe once(?) in ~20 years.
- Even if you do find a set, it will probably be very expensive.
- Sounds like Alembic will not sell/install it in a Fernandes, which I can understand - it could create even more of a confusing knockoff situation. So you (or a shop) would need to do the install yourself. I don't think this would be that difficult; the cavity dimensions are the same.
- Pickup dimensions: Back when I was looking for a replacement for my dead FAG-170 pickup, Mica pointed out that the Series pickup dimensions have changed since the late 70s (when Fernandes presumably copied the dimensions). So even if I bought a new Alembic Series guitar pickup to replace the FAG pickup, it would not be a perfect fit. So to use an Alembic pickup, you may either need to do some routing, or end up with some "dead" space around the pickups. For me, that was a deal-breaker.
In my case, I ended up building a custom replacement pickup. It works great, and sounds identical to the other (working) pickup. I can send you a link to a forum post I made about it, if you're interested.
For this guitar that is now on eBay: It COULD be restored. When the seller says that it includes the original "preamp", they might mean the original on-board electronics, which would be pretty much essential. It sounds like the electronics have some issues that would need to be fixed. This will probably be difficult for an average guitar repair person, because the electronics are way more complicated than a typical guitar, but someone who is good with circuits could fix it (it might just cost a lot, unless it's something very obvious like a loose wire). I have a full schematic of a FAG/FAB, if you're interested.
The guitar would probably work PRETTY well at that point, it's just a bit weird with that EMG replacement pickup. It could be replaced with a custom-built replacement like I did, though. It didn't cost me that much, but it took a LOT of time! For me, restoring a super-rare guitar was a fun project, and was worth it.
