I have six of these things in the shop right now and was noticing the revision numbers on the logic boards. The first I have is Rev. C going up to Rev. G-1 - which is the interesting one as it allows for HD floppies. This revision is a small series of jumper wires and a three cuts to the group of traces just to the right of the Floppy Drive connector. The other revisions appear to only relate to parts mounted on the boards - different brands of connectors, reset switch changed, etc. as all the ICs stayed the same as far as we could tell by an eyeball examination. Making these changes does appear to enable 1.44 drives on revisions that previously only had 720 drives so I am going to write it all up - but for now you can look at the pictures of the jumpers and cuts and try it yourself...I believe you need the 40 meg version of the Bios installed as well (2 X 27512 Eproms). ftp://ttl.arcadetech.org/TTL/Test_Equipment/Fluke/9100A/Photos I will add Rev. C photos later so you can see the differences. If anyone has anything later than Rev. G-1 please get in touch in case something else was added.... John :-#)# _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org Archive site: http://seven.pairlist.net/pipermail/techtoolslist/