Make your own transit card for your 1541/1571 drives. 12-09-99 The transit card (sometimes called a "head vibration protector") that comes with a new disk drive is an important tool. The card is made of stiff cardboard and is the same size as a floppy disk, except for the tab that sticks out of the front end. That tab, unlike a disk, pushes the head stepper mechanism back to track zero when the card is inserted into the drive. In addition, when the drive door is latched down, the heads are allowed to rest on the card and are therefore prevented from hitting each other in the 1571 and clone drives. More importantly for the 1571, the head lifter mechanism is released, so any physical shock to the drive will not bend the head mount. This is -very- important when the drive is to be transported or shipped! A scrap disk will protect the heads and mount, but will not keep the stepper mechanism locked in place. One use for the transit card is often overlooked. Normally the drive "parks" the head over the directory track (18), but when a 1541 head moves past track 18, under some conditons, the drive can sometimes become "lost" and fail to respond to the computer. Some disk errors can do that, as can turning the computer or drive off before a program has reinitialized the drive. Even if turned off and on again, the drive will not be able to read a disk. You can send an Initialize command or format a disk to pull the head back, but a quicker way to recover the "dead" drive is to turn it off, insert the transit card to push the head back, remove the card and turn the drive on again. That method does not require that the computer be turned off, so any program running is not lost. Early 1541 drives were shipped with a card, the CBM 251171-02. It would fit only the 1541 because the tab on the front was quite large (about 1.5" wide), and centered on the front of the card. A later version of the card, a CBM 251171-03 had a smaller offset tab, and was used in the 1571 drive. That same card will work in a 1541 as well. I tested the later card in all my 5.25" drives and it fits and works with all of them. That includes the 1541 (both ALPS and Newtronics), the 1541-II, both versions of the Amtech/Blue Chip (1541 and 1571 clones), the Excelerator (Oceanics) 1541 clone and the MSD SD-2 dual drive. You can make your own card out of thick (not corrugated) cardboard or plastic. It should be stiff enough so the tab does not bend when the card is inserted, but not so thick (more so than a floppy disk) that it will not fit the drive. I will include the dimensions here. Note that the tab is offset to the right slightly, unlike the early 1541 tab which was centered. By the way, if you have one of the early cards, you can easily trim the tab to match these dimensions. If you're making a card from "scratch", you can use a disk as a template (but don't forget the tab). Insert this end of card into drive. tab depth = 7/8" or 2.2cm .--------------. | | <--------- 2 1/4"----------->|<-- 1 1/8"--->|<------- 1 7/8" ------> 5.8cm | 2.8cm | 4.8cm | | .----------------------------' `-----------------------. | | | | | | | Card (less tab) measures 5 1/4" (13.4cm) square | | (same size as floppy disk) | | | | | | | | | | . | | . . | | Hole in center of card . | | . . | | | |<----- 1 7/8" -------> .<-- 1 9/16" diam--> .<----- 1 7/8" -----> | | 4.7cm 4cm 4.7cm | | . . | | . . | | . . | | . | | ^ | | | | | | | | | | | 1 7/8" | | 4.7cm | | | | | | | | | | | V | `-------------------------------------------------------------------' Ray Carlsen CET CARLSEN ELECTRONICS... a leader in trailing-edge technology.