My two favorite JV‑880 Expansion Boards are SR‑JV80‑05 (WORLD) and SR‑JV80‑08 (KEYBOARDS OF THE 60's & 70's). Why? The WORLD Expansion Board contains the waveform called Cimbalom and it is spectacular! The Cimbalom is, in my opinion, THE most important instrument in Hollywood. That's because I have been addicted to 60's & 70's Action/Mystery/Spy movies since forever. The old Mission Impossible TV shows feature the Cimbalom prominently and this instrument was made famous by Lalo Shiffrin in countless OST's. "Telefon", "Three Days of the Condor", "Star Trek: The Motion Picture" and just about every Cold War Spy Thriller ever made have some great OST's using the Cimbalom throughout. This is one of the highest quality Cimbalom samples I've ever heard. This Board also contains a gigantic library of some really bizarre sounds from all over the world. It's not your average sample collection. If you want some weird and strange sounds... this is the one. The KEYBOARDS OF THE 60's & 70's Expansion Board is another favorite because of the wide selection of quality waveforms featuring the Mellotron, Clavinet, Farfisa and Rhodes/VOX/Hammond Organs... 255 in all from this classic time period in music history

Watch out for this one! Many eBay and reverb.com buyers (including myself) have been burned when they bought this board. It usually sells for a low price which makes it tempting but it's very deceiving. The graphics make it appear to be the SR‑JV80‑04 VINTAGE SYNTH Board but it's not. This is a "Tryout Board" and only contains a small collection from the first five SR‑JV80 Boards. None of the Patches on this board are compatible with the JV‑880. You can only load waveforms to get a feel for what some of the first five boards will sound like. It is completely incompatible with the JD‑990. Also, none of the Patches on this board will work with the JV‑80, JV‑90 or JV‑1000 synths. Likewise, the SR‑JV80‑97 EXPERIENCE II and SR‑JV80‑98 EXPERIENCE III "Tryout Boards" exhibit these same faults with the above mentioned synths


source:

Owner's Manuals for SR-JV80-97, SR-JV80-98 and SR-JV80-99 Expansion Boards state:
      "The JV-80/880/90/1000 allows you to use only waveforms"
           (sic) It won't load any of the Patches on these three boards
           Omitted from the SR-JV80-99 Owner's Manual so... I will assume it's the same

      "This 'tryout' expansion board features unique specifications which make it incompatible with the JD-990"

This is a press release from Roland Corp. Japan which was published on January 27, 2017:

To Expansion Board SR-JV80 Series Customers
"Thank you very much for your patronage of our products on a daily basis. The Expansion Board SR-JV80 series has been in production for more than 20 years since the initial production, electrolyte in use may rarely leak due to aged deterioration of the electrolytic capacitor used. If electrolyte leaks out, in the worst case there is a risk of smoking. Customers who are currently using the SR-JV80 series with sound module or synthesizer should stop using them immediately."


I'll need to add my 2 cents worth here:

I own eight SR-JV80 Expansion Boards. Every one of them had a defective electrolytic capacitor which leaked onto the PCB and corroded some traces. Luckily, I was able to repair all of them. The claim made by Roland Corp. Japan downplays the extent for the number of defective boards by saying, "...electrolyte in use may rarely leak...". I think that is total bullshit. In my opinion and from my experience, this failure will occur sooner or later on all SR‑JV80 Expansion Boards

The recommended fix which I have performed is quite easy and inexpensive. Carefully unsolder and remove the electrolytic capacitor, clean the area with ISO and a Q‑Tip and inspect surrounding traces and components for any damage caused by the corrosive fluid. I've seen videos where people will twist an SMD capacitor to remove it. Don't do that because you run the risk of pulling fragile traces off the PCB. Do it the right way and unsolder it. Replace it with a high quality, brand name SMD capacitor like Nichicon or Panasonic. Some owners have posted online that they used a through‑hole radial electrolytic capacitor or a regular MLCC capacitor because, "...it was easier to solder in place". Please Don't Do That! Cutting corners with complex synth circuitry is always a bad idea. Perform the repair the correct way and use an SMD electrolytic capacitor

The original specification is for a 100µF/6V, 6.3mm diameter SMD capacitor. I recommend using one with a higher Voltage rating. Why? It's entirely possible that the original circuit design requires more than 6V which may have caused the capacitor to work overtime and contribute to the failure. It is interesting to note that when Roland Corp. Japan replaced capacitors on defective boards for their customers, they used capacitors with a higher Voltage rating

Any of these three high quality 100µF capacitors will work as a suitable replacement:

The ROMulator is one of the coolest tech gadgets I own. It effectively lets you program any of the available twenty‑two SR-JV80 Expansion Boards onto your own blank ROMulator card. Now you can use any SR-JV80 Board in the library!!!