BLUE CHIP BCD/5.25 DISK DRIVE 6-18-2012.
BLUE CHIP BCD/5.25 DISK DRIVE FCC ID E2250FMBL-138 latest updates and/or corrections 6-18-2012 This drive is a clone of the Commodore 1541 and uses the same CBM DOS ROM V2.6 code in its two socketed EPROMs. JiffyDOS for the 1541 will work. The mechanism features a direct drive motor (no belt). This drive and the Blue Chip and AMTECH 1571 clones are powered by a transformer-only external power pack which outputs two voltages: 16VAC at 0.8A and 9VAC at 1.5A. Rectifiers, filters and regulators are all inside the drive. If I didn't have a power pack, the transformer out of a 1541 would work to supply those voltages. The four pin power connector is unique and would be hard to find, so some type of replacement connector would have to be fabricated. The connector pinout is as follows: 9VAC -----O O----- 9VAC 16VAC -----0 O----- 16VAC The drive was shipped as device #8 and requires internal jumper changes to select drive 9, 10 or 11. The jumpers are not marked but are near the 6522 VIA chip at the front left side of the drive. The jumpers connect to pins 15 and 16 of the IC. If your Blue Chip drive is not working, I have bad news. I have two of them with the same fault... the stepper doesn't move. Unless the head is manally moved over the directory track, the drive can't read a disk. The failure is apparently caused by a proprietary IC, the disk controller IC on the mechanism board. It's a 40 pin MEL9501-40 and I can find no information for it. An oscilloscope shows no data on any of the pins of that IC. Unless a replacement IC can be found, the drive is not repairable.