-> On Sun, 5 Nov 2000, Claude wrote: -> -> > Bill Dawson wrote: -> > > disks. The only markings on Q1, TO-92'ish, are A854 (date code or -> > > 2SA854?) and S G D. I think this device is in the circuit to save -> -> > Quickly I would say its a 2sa854 very common but S,G,D should be for -> > Source, Drain, Gate for FET transistors...could be a fet with that -> > number... Yes, FET, not SCR. I know what S, G and D stand for. Lack of sleep contributes to mistakes. -> -> I use this part at work all the time. It is a 2SA854, simple bipolar PNP, -> I(c) of 500 mA maximum, just a general-purpose transistor. The SGD on the -> bottom is probably a lot/date code. Well, the leads are not evenly spaced. The S and G leads are closer together than the G and D leads, and the S, G and D markings are exactly over each lead. -> The leads are, facing the side with -> the markings on it, emitter/collector/base. This is why shorting the -> first two makes it work. -> -> Make sure you have proper signal at the base, then replace if necessary; a -> 2N3906 will sub but has a different pinout and (I think) not quite the -> same I(c) rating. There is a spec sheet at the Rohm website. I guess I may have to draw up a schematic of the circuit to figure out what's going on, if no one has it. I didn't write down the part number of the stepper motor driver, but I think it needs more current than a small signal transistor can pass. Bill -> -> Richard Schauer -> rws(a)enteract.com ->

Tony, Thanks for all the info. I'm beginning to understand some of this CP/M formatting now. <SNIP> -> You were very lucky it was as little damage as this. Normally getting the -> +12V supply on the +5V pin wipes out every logic chip on the drive... After getting away from the problem for a while and sleeping on it (actually, thinking about it before I fell asleep), I agree with you that what is controlling the FET is the problem. There are only IC's on this floppy, not counting the spindle drive. One is the stepper controller, the other is a QFP mounted like the gate array on the Amstrad PCW8256. Perhaps one of its outputs is blown open? -> > was no power to the stepper motor controller IC. Q1 ( I think it is a -> > small SCR, since its three legs are marked S, G and D) which -> -> That would make it an FET. Source, Gate, Drain. Thanks for the correction. -> > switches/regulates power to the stepper IC seems inop. When I short the -> > S and G leads, the controller IC gets +5V, the stepper motor works and -> -> One thing puzzles me here. Gate (G) is the control electrode of an FET -- -> like the base of a transistor of the first grid of a valve. If shorting -> that to Source turns on the power, then most likely the device itself is -> OK, and the control electronics isn't driving it. -> -> Can you trace out the circuitry connected to the 3 pins on this device? The Bondwell is back together, and it may be a while before I get to it again. That is why I was hoping someone had a schematic for the floppy. I don't know if the drive is original or not. Why would a DS drive be in a unit that only uses one side. The EPSON SMD-170 is a SSDD 400K, but I can't find any info on it either (other than a mention on the web of it being a "SSQD" 3.5". -> -> -> > the floppy drive functions. The Bondwell now will boot, format and copy -> > disks. The only markings on Q1, TO-92'ish, are A854 (date code or -> > 2SA854?) and S G D. I think this device is in the circuit to save -> > power; perhaps when the floppy is not selected, the head stepper is left -> > to float free. Correct me if I'm wrong about this. The floppy is an -> -> Yes, that's quite normal. Many drives, not just in laptops do this. -> -> > early 720K DSDD (even though the Bondwell is only SSDD) Epson SMD-180B. -> > -> > Question #1. Does anyone have schematics for this drive? -> > -> > Also, I tried to build a custom disk definition for the Bondwell 2 for -> > 22disk v1.44. I used Anadisk to evaluate the Bondwell floppy format, <snip> -> I think you're getting confused as to the 2 types of interleave... Correct again. I was confusing the physical and logical interleaves, specifically which fields in 22DISK were for which one. I can use ANADISK and see the physical format, and if a text file follows this format, no problem. If it doesn't, then I have to locate a file or files that I can compare it with (like I did with STAT tonight on the Otrona) to ascertain the logical format. So, as I understand it, ANADISK will usually give me the physical format (which is what follows the 22DISK SIDES keyword?), and if it is a standard interleave, no problem, I just specify the e interleave with SKEW and leave SIDES in numerical order? But what if there is both physical and logical interleave? How do I define this? I have an unknown CP/M disk with three files on it that ANADISK reports as 1:1 the interleave, and I can read the directory OK with 22DISK, yet the files still come out jumbled when transferred to DOS. For the most part in CPMDISKS, I noticed that if SKEW is specified, the sector order is straight numerical, and if SKEW is not specified the sector order is defined after SIDES. But there are some definitions where this is not true. I also noticed that some SIDES definitions have the first sector as 0, and others with 1. Does ANADISK report the first physical sector number (0 or 1) correctly? BTW, here's a working definition for this Bondwell 2: BEGIN BON3 Bondwell 2 - SSDD 3.5" DENSITY MFM ,LOW CYLINDERS 80 SIDES 1 SECTORS 18,256 SKEW 2 SIDE1 0 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17 BSH 4 BLM 15 EXM 1 DSM 174 DRM 127 AL0 0C0H AL1 0 OFS 2 END As an exercise, I worked up a definition tonight for an Otrona Attach?, DSDD, not looking at the definition for it already in the CPMDISKS.DEF. I managed to get it all correct except for ORDER EAGLE. I had used ORDER CYLINDER, but couldn't get it to work correctly. EAGLE is not defined in the documentation I have. What does EAGLE define? I know the Otrona disk has a strange layout. -> Physical interleave, which is what Anadisk detects, means that the <snip> This I knew. <SNIP> -> AFAIK Anadisk doesn't know anything about Logical interleave -- the -> interleave it detects is the physical interleave determined by reading an -> entire track and seeing what order the sector headers appear. This also. -> In fact it's impossible to determine the logical interleave unless -> there's some known data on the disk -- the only way to determine it is to -> read said data and then work out what order you should have read the -> sectors in. Yes, I well recall the recent discussion about this. -> the fact that a known file (dump.asm) reads correctly under Anadisk -> without logical interleave suggests that there is _no_ logical interleave. Correct again. Like I mentioned earlier, my main point of confusion was how to tell 22DISK what the interleave is, and I understand it now if there is only physical interleave. What if it is an oddball physical that can't be defined by SKEW? I still don't think I know how to define a logical interleave or a physical and logical interleave mix for 22DISK. -> -tony -> Thanks again, Tony, Bill