The Power Computing PC720B combines an external drive, drive B boot switch and Blitz Turbo Copier in one package.
These drives contained either NEC or Sony drive mechanisms and were a high quality competitor to Cumana.
My drive contains a Sony MPF-110-01.
Download the instructions here (2Mb).
Download the software here (15kB).
Unpacks to pc720b.msa (360k).
Contains blitz22.tos
Thanks to Total Eclipse and Adam Hill!
The Blitz Copier (and Blitz Turbo) system was originally sold by Power Computing from 1989. It uses the printer port for some signals and an external floppy drive.
This is a screenshot from Blitz Turbo:
The documentation says the software supplied with this drive disk contains BLITZ.TOS not the usual BLITZ.PRG or BL_TURBO.PRG as supplied with the Blitz Cable. This looks like a special version of the software because this version of the hardware does not use the printer port.
This is a screenshot of the software supplied with the PC720B:
Position 1: Drive is on and operates normally.
Position 0: Drive is off.
Position X: Drive is on and booting from drive B: is enabled.
Default for normal drive B use: 1
Switch 2:Position A: Drive is in Virus Blocker mode. All write access to either drive are blocked (so drive is effectively write protected).
Position 0: Drive operates normally as a standard ST drive.
Position B: Drive is in Blitz mode and can be used with the supplied Blitz software to backup disks.
Default for normal drive B use: 0
This drive is supplied with a 5V transformer at 1A (5W). The connector is 2.1mm x 5.5mm x 12mm. Centre Positive.
The plug on my transformer has insulating sleeves on line and neutral pins and a correctly sized 3A Marbo fuse. In the days of customer wired plugs it is best to check these. Sometimes people would use a 13A fuse on everything.
Rather unusual for the time the outer case is secured with 4 tri-wing screws. The outer case slides off to access the drive inside.
A bit box which contains this bit is available from any hardware store or even Bargain Buys or Poundstretcher in the UK.
Power Computing placed a full page colour advert in Atari ST User Magazine Issue 68, Page 2 (Oct 91) and in ST Format Issue 27, Page 39 (Oct 91) to show all the features of the drive.
At £65 it was very competitively priced. Cumana drives were £79.99 at that time.
| Drive Model | Power Supply |
| PC720 | Mains Cable. Internal Transformer. |
| PC720P | External PSU. |
| PC720E | Extender to the joystick port. |
| PC720B | External PSU. Blitz Turbo built in. |
From info-coach:
"The Blitz software that uses a specific cable is able to reproduce some protected floppy disks that can't be reproduced by software only. However be aware that in most cases even if the copy works the copy is quite different from the original and therefore this cannot be considered as a preservation of the original."
The Synchro Express was meant to be a bit higher quality and sold for £35 and the Power Computing Blitz Turbo was sold for £15, but Roger Price Computing was selling them for £8-£12.
A friend of mine couldn't copy Batman using Synchro Express so we assumed it couldn't copy CopyLock Protected Games. Chances are it had RNF errors on other tracks and not the long sector (Track 0, Sector 6) but he wasn't able to check that.
In the early 90s one stall at the local market used Blitz to copy all disks (including public domain) but about 1 disk in 3 had bad sectors and was usually unbootable. We only ever went to the places that used FastCopy 3 for reliability. Blitz is a technical curiousity but shouldn't be relied upon for software preservation. Sometimes copying the protection track from the original using Blitz and the rest of the disk using FastCopy 3 is good enough to make a casual copy.
The fastest way to copy unprotected disks reliably was by using FastCopy 3 or higher.
1Mb of memory and an external drive is useful to copy disks in one pass.
There is a GAL16V8-25LNC chip on a custom circuit board in the drive.
This might be the limiting factor for the lifespan of these drives. There have been cases where these chips have failed. The logic file for the GAL is unknown and there are no known spare chips. You have to get them from working drives.
Photo credit: Andy Bailey
After 30 years these drives may be starting to fail. They have exceeded their normal service life, but they may be able to be repaired.
With the Sony MPF-110 there are 2 surface mounted capacitors that should be replaced:
1x 47uF 16V
1x 47uF 25V
There are 3 really tiny screws on the back of the drive case. I had to use a magnifying glass, a no. 1 precision screwdriver (Blackspur) and a magnetic bit to lift them out. Do not try to prize the lid open with a screwdriver!
The drive heads can be cleaned with 99.9% Isopropyl Alcohol (IPA).
Some sources say the rails should be regreased with a tiny amount of white lithium grease but Macintosh 800k Sony MP-51W and MFD-51W series floppy drives were originally greased with Molykote EM-10L. Molykote EM-10L is no longer made but EM-30L should be a suitable replacement. If handling EM-30L please observe all safety precautions. Use at your own risk!
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