TR-505 ROM

The TR-505 is very similar to the 626. Same sound chip, same general design.

The audio is encoded as 8bit, mono, linear PCM @ 25Khz. Standard Roland fare.

The sound ROM(IC11) has a smattering of jumbled data and address lines that makes it hard to read/write. Most of the pins can be unscrambled in software but, the actual chip(TC531000P) has a non-standard pinout. Its A16 is where most 28pin chips have an output enable line. A little rewiring is required to read it and a larger chip is required to duplicate it.

Even with the pins in order, the sounds are still scrambled. The short interleaved samples and the long chunked-up samples are sorted just like the 626, so I'll just reiterate a bit.
The short samples are combined: one sound on the odd addresses and one sound on the even addresses.
The long samples are put into "piles": A,B,C,D. Each pile contains every fourth byte. A has every fourth byte starting from 0, B has every fourth byte starting from 1, C every 4th from 2, D 4th from 3.

As one final point of confusion, A0 is inverted. Some basic glue logic was used to generate A0 (and A13-A16) and it was probably just easier to invert A0 in the ROM rather than invert the signal. Based on the binary I've found, no other address lines are inverted.

Here is the ROM table from the service manual.

ROM unscramblers

A set of python scripts for decoding and/or unscrambling various drum machine ROMs. 
They have been tested with python 3 in Windows.

TR-505 unscrambler assumes the ROM binary already has the address and data lines in the correct order.
It fixes the inverted address line, recombines the cymbals and separates the short, interleaved samples.

By special request, I've uploaded a 505 re-scrambler. Again, this doesn't take into account the jumbled address/data lines. You'll need to use a tool like EPROM pin swapper to reorganize things. Even then, the replacement EPROM will need to be rewired a bit. I touch on it in my TR-505 post.

TR-626 unscrambler accounts for the swapped address lines.
All interleaved samples are separated. All cymbals are recombined.

626 scrambler accepts a WAV file as a command line argument. Outputs a bin file ready to burn to an EEPROM.

DR 220 expander takes the 220's 8bit mu-law encoded ROM and converts it to a 16bit PCM binary: effectively a headerless WAV file.

Mu-Law expander takes most mu-law encoded ROMs (eg. DMX, Linn Drum, Drumtrax) and outputs a 16bit PCM binary.