This is a transcript of a document that came with my Xpander that i haven't previously seen on the Internet, so here it is:
- Xpander MIDI controller notes

If you need to update the software in the Xpander you'll need these files (and a EPROM burner):
(Main 1.2, Voice 1.4 )
- Xpander ROM images

Here is a PDF describing the 0ddernmart audio in modification on the Xpander.
I havn't tried this myself. If you do, please let me know the results ;-)
- Oddernmart Audio Input Xpansion

The early Oberheim Xpanders were manufactured in the US, the later ones in Japan. Here is a bunch of photos from the inside of two different Xpanders:
- Xpander inside
These photos can be helpful if you need to service your Xpander.

Even more helpful perhaps:
- Xpander Users manual
- Xpander Service manual

Most of the components used in the Xpander are easy to find and replace. But there are some that isn't. The rotary encoders are pretty rare, i've seen them on eBay but not very often. If they start jumping numbers twist them around for a minute and they will most often behave well again. The displays are very rare but no one seem to have any problems with them either so no need to worry. The VCO chip (CEM3374) is also rare, but it does not seem to fail often. The most common problem is the filter. If the filter fails the voice sometimes die. Replace the chip (CEM3372) and usually it starts to work again. (Hint: try swapping filterchips between voices to see if this was the problem) The filter chip is luckily still easy to find. Another common problem these days is failing power supplies. This is a major problem because it can destroy other parts of the synth. Make sure to replace the large electrolytic capacitors in the PSU every 15 years or so (uh-oh, the xpander was made 1983). The battery should be replaced too because it can start to leak. The acid from the battery can do seriuos harm to your Xpander.

Lots of patches to download here:
- Xpander patches

HI MOM!, I found the little easter-egg "Page 3" on my Xpander:

Matrix 1000:
All the names of the original Matrix-1000 patches in a convenient format:
- Microsoft Excel version
- HTML version to view online
- HTML version in a zip archive for download.

Interesting places to visit:
- XevenT, xpanding your ears
- Matrix-12 resource center, also applies to Xpander
- A collection of interesting little files at MusicMachines
- Lots of info here (click Oberheim, then Xpander on the next page)
- Even more links