RISO MZ1090 drums compatible with MZ990?

[superphamicom]

Hi, I'm interested in purchasing an MZ1090 drum listed as a "10/8." Not sure what the 10/8 means, but in general are 1090 drums backwards compatible with 990s?

thanks in advance to anyone who can help!

[jermyth]

Re: RISO MZ1090 drums compatible with MZ990?

No they are not compatible nor is the newer 10/8 backwards compatible. MZ 990 & 790 drum is S-4714. MZ 1090 & 890 is S-5257. A 790/990 drum can be converted to the 1090/890, but that is a permanent change not a simple flip a dip switch. Need a S-5258 conversion kit.
Good luck.