Jos Dreesen wrote: library Congratulations! The 4052 indeed a rare beast. Hopefully the ROMs in the machines haven't gone south. Earlier versions of the 4052 (and 4051) used a weird Motorola EPROM for the firmware that has a tendency to forget. It is a weird pinout, and isn't directly compatible with more standard EPROMs. I suggest that if you have an operational machine that you pull the ROMs (carefully), and read out their contents (assuming you have a way to read them) to archive them in another form, should you need to make new ones someday. There are quite a few different versions of the firmware, all with particular little quirks that match up with hardware tweaks, so one version of firmware may not run on certain boardsets. As far as I've been able to find, there just doesn't seem to be a suitable replacement for the drive bands. I've pillaged them from good tapes to rescue tapes with important content. Thankfully, I have a floppy system for my 405x machines, and I've copied most all of the tapes to (8") floppies, and then made dupes of the floppies. I just don't trust the tapes anymore. I wish that there was a way to image these floppies by reading them with something else, but I just haven't had the time to dig into it. One thing to be aware of with the tapes is "stiction" of the tape if you do replace the drive band. After stored for a long period of time (especially if stored in higher temperatures, e.g., attic, metal shed, etc.), the tape "sticks" to itself. If you just replace the drive band without first winding the tape fully in both directions to break the stiction, you may well break another drive band. You may find tapes that are stuck together so badly that they can't be salvaged. I have found more than a few like this. Also, watch out for the capstan roller in the 4052 drive. It can turn to goo, or end up with flat spots (especially if a tape was left in the drive for a long time) that can really mess up a tape if you put it in. If this happens, you have to figure out a way to rebuild the capstan so that it drives the tapes properly. It's a pretty tight tolerance on the size and material for the roller...too much pressure and the motor will stall, and not enough, and the tape will slip. Clean the tape head frequently, as old tapes tend to drop oxide pretty bad. These drives are very sensitive to gunk on the heads. The mold on the tape can cause the oxide to flake off, leaving bare mylar base. This clearly makes the tapes unreadable, and makes a mess of the tape head. The tape drives used in the 405x machines were not so great at interchange..if a tape was written on one machine, it more than likely would have problems being read on another. There is an alignment process that can help dial in the drive -- it is listed in the service manual (hopefully you got one of those).' Best of luck, Rick Bensene The Old Calculator Museum (and a few old computers, too) http://oldcalculatormuseum.com