On Nov 7, 2011, at 2:57 PM, Glen Slick wrote: Right, I remember, I conversed with you on a different forum (and got your ROM and PAL images). It's interesting; dropping the ROM image into new EPROMs won't even let me boot the code (the 8086 part works, because it copies it to the host and I can start executing it, but it won't let me use the board; I don't recall the exact error message, but it's something like "NOT A SCSI BOARD" and I haven't had time to disassemble that part of the PDP-11 executable). Burning the CSR PAL to a new GAL didn't change anything, which I suppose is good. I put the original back in so I wouldn't have to use up one of my relatively small supply of GAL22V10s. :-) None of the other PLDs are socketed, so pulling them just to read them is not something I'd do on a whim. I suppose I ought to check what the firmware's criteria are for rejecting the board. That might give me at least a bit of a hint as to what's going on. - Dave

On Nov 11, 2011, at 7:45 PM, David Riley wrote: Before anyone calls me out as a dummy: yes, a 93C06 should probably work fine (unless someone can think of a reason they wouldn't). They're still not easily available, but worst case, I can probably modify the few constants in the ROM which determine the address length and modify it to work with a 93C46, which is still available. If that turns out to be the case, I'll gladly release a patch. - Dave

On Nov 11, 2011, at 8:15 PM, Toby Thain wrote: OK, I built up a rig for reading the EEPROM (I don't have any 93C46 chips yet, but I'll check to make sure the same algorithm works on them... it's a pesky line of chips because unlike most SPI devices, the bit strings are not multiples of 8. The read command also inserts a dummy zero bit before the data, so the read command is actually one bit longer than the write bit. It's a mess. Anyway, I verified that my old EEPROM is, in fact, still basically good (Xeltek's algorithm for the SuperPro 280 just doesn't work, and I don't have a digital scope to see what it's doing wrong), but I must have done the same thing a year or so ago that I did almost as soon as I got it working again. Both disk and tapes are set to zero in the unit count config word (which they took the trouble of protecting against corruption with a "magic nibble" but didn't bother bounds-checking, as described below). In short, MAKE SURE you don't accidentally tell it during configuration that you have 0 disks and 0 tapes, because if you do, the 8086 crashes when it's trying to load the disk config data. It uses the total number of units to loop through and read n unit configs out of the EEPROM and store them at [0x500 + 2i]. The problem is that the 8086 LOOP instruction predecrements the counter and checks the result for zero; if the counter is zero on the first instruction, it thus goes for 65535 iterations. Obviously, that causes problems, since we're writing memory. I made a patch for the ROM to fix this problem, because it doesn't appear to be fixed in the A8 revision either (at least, I assume; I haven't actually tried the A8 since I've replaced the EEPROM, but I'd like to think it'll work). This bug will brick a rather hard-to-find board if you make a simple mistake while typing late at night. There's an extraneous MOV instruction (probably the result of a poorly-optimizing compiler) in an opportune location to run an 8-bit add on the disk and tape numbers which JUST HAPPEN to be in registers that get thrown away shortly after. The MOV instruction gives me 5 bytes, and it looks like I only need 4 plus the trailing NOP for the ADD and JZ. In any case, I'll test it later this weekend when I've had a chance to dig up some appropriate EPROMS out of the parts bin and made sure my UV eraser still works (it got dropped during the move, but it's been dropped before and nothing looks visibly broken). I doubt I'd really run into copyright problems from a completely defunct company for a very obsolete board if I posted the fixed ROM image. Any thoughts? If the fix for the A7A revision works (that's what came with mine and it's what I have installed now), I'll make one for the A8 (which Glen Slick provided for testing) once I can disassemble enough of it to find the offending code (and hope the extra MOV instruction didn't disappear). - Dave

On Nov 12, 2011, at 2:46 PM, Glen Slick wrote: I did! It's in the lower bytes of words 3 and 4 in the EEPROM (LSB first). There's no mechanism I've seen for setting that in the firmware, but if you're already putting it in a ROM burner, you might as well fill it up. If it sees 0xFFFF for the serial number, it assumes the chip is erased and displays 0 instead of 65535. - Dave

On Mon, Nov 7, 2011 at 3:32 PM, <cctech at vax-11.org> wrote: It's not clear to me what is used for the RS-232 interface on the CQD-220. I don't see any obvioius RS-232 interface chips. There are a handful of diodes and resistors adjacent to the RS-232 port. Maybe those make up the RS-232 interface. There is no UART on the board. I have never been curious enough to try to trace the signals to try to determine how the serial interface is implemented. -Glen

On Mon, Nov 7, 2011 at 4:40 PM, Eric Smith <eric at brouhaha.com> wrote: The only 8-pin device on the CQD-220 is the NMC9306 EEPROM U11. I have a high resolution scan of both sides of the board here: http://sites.google.com/site/glensvintagecomputerinfo/cmd-cqd-220-scsi

On Nov 7, 2011, at 6:48 PM, Glen Slick wrote: It's all GPIO coming from a parallel register (addressed by one of the decoding PALs) and then bodged up with a series of diodes and caps to vaguely resemble RS-232. It's bit-banged in the 8086 (I've disassembled that part, at least). I don't get any activity whatsoever on the port, though, which leads me to believe something is wrong elsewhere in the logic. Looking at the input line, at least, on my scope shows me that the RS-232 line is getting through (at proper logic levels) at least to the GPIO latch where it's supposed to be. One of these days it might be useful to figure out something resembling an equivalent schematic, but since it appears to be a 4-layer board (with lots of lines going under soldered-down chips besides), it doesn't look like anything I'll be doing soon. I have some new 53C90A parts on order from recycledgoods.com as well as some 53CF94s for some personal projects. If anyone is looking for replacement ones, they have an OK deal on them now (though they gouge on shipping, acting like each chip is a pound). - Dave

I doubt it. I'v got hundreds (literally) of 1489s in use here, and I've neer had one die by being connected to an active RS23 line while powered-down. And I've done that often enough... I thought the RS232 spec required that you cna conenct any pin (even an ouptu) to any valid RS232 voltage level without damaging anything, even if the device is powered down. -tony

Oh, sure. You can blow up 1489s electrically. One other thing that kills them is a high voltaeg spike on the input, perhaps from a lightning flash near a long terminal cable. But I don't think that connecting a valid RS232 voltage to the input of a powered-down 1489 will damage it. I never has for me, anyway. -tony

Yes, you are probably (almost certainly) right. However, since the inputs are voltage-sensivity, you should be able to apply any votlag between -25V to +25V to any othem without damage (since that's what a valid RS232 ooutput could do) even with the device powered-down. I cna't rememebr how many outpus there are on na RS232 conenctor, but it seems to me that the spec means you could short all of them together, have all but one in one state and that one in the other state without damaging anything. And 'all but one in one sate' is going to be a much lower inpedance voltage source than a single output. RS232 ports (properly designed ones) are fairly hard to damage electrically. -tony

And hoe many mains leads do you have with DB25 conenctors on the end :-) Of ocurse if you want ot damage an RS232 port you cna do it. My point was that if you miswire the cable, or connect soemthing else with a DB25 or DE9 conenctor to it, it's unlikely to damage the RS232 port (it may damage the otehr device, particualrly if it's expecting TTL level signals). If you are conencitng 2 'RS232' devices together and you miswire the cable it's unlikely to damage anything (in fact the spec implies it mustn't damage anything). Powering down one devi9ce leaving the other powered up shoud do no damage either. -tony

On Thu, 10 Nov 2011, Sridhar Ayengar wrote: My serial killer only provides power to pins 1 through 8 and 20. Therefore, it is a DB9.

On Fri, 11 Nov 2011 20:52:35 +0000 (GMT) ard at p850ug1.demon.co.uk (Tony Duell) wrote: Yes, but easy to fix with a gender changer. -- \end{Jochen} \ref{http://www.unixag-kl.fh-kl.de/~jkunz/}

On 10/11/11 9:28 PM, David Riley wrote: Am I the only one who doesn't find this funny? For a group usually obsessed with FIXING things, it's a strange obsession... like the doctor who studies serial killers in his spare time... --T

On 10/11/11 10:02 PM, Mouse wrote: Yeah the deadpan came through for me too. It was the kind of remark that leaves an awkward silence one is tempted to fill with, "...oh. So what do you use *that* for?" --T

BTW, it is always nice to remember: Today Sridhar gets older...Happy birthday, man! :oD

"kill ethernet ports" :o)

Some of us prefer _repairing_ such non-workign hardware... -tony

On 11/11/11 8:07 AM, Mr Ian Primus wrote: mains power to data connectors" was a sort of rite of passage... something every geek has done at some point. I'd wager that most of us have some kind of EtherKiller or related device hanging around, if only for the shock value when someone else sees it. And, of course, for demonstrating the meaning of the phrase "magic smoke". Was never the slightest bit tempted. Goes against my grain completely. --T dead hard drive even deader... with fireworks! > -Ian

On Fri, 2011-11-11 at 05:07 -0800, Mr Ian Primus wrote: I have a cable which consists of a UK mains plug, a length of low-current mains cable... and a bare end. I use it for testing power supplies, specifically AC-DC "industrial" or "embedded" PSUs with screw-terminal connectors. I don't doubt it. But I prefer a hammer. A much more tactile (and satisfying) way of ensuring a bricked HDD doesn't find its way back into my spares pile... Plus it puts ruddy great dents on most sides, thus making it damn obvious that the HDA and PCB are completely buggered. -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

Alexey Toptygin [alexeyt at freeshell.org] wrote: Someone I know on facebook posted photos the other day of a disk he shot (with a handgun). I like to keep the magnets. I've not found a use for the spindle motor: can you actually run it without the drive electronics? CD/DVD/FDD motors seem better for that. Antonio arcarlini at iee.org

The spindle motor in most small HDDs is a polyphase thing, a bit like a stepper motor. Sometiems, particularly on older units, there are hall effect devices to detect the rotor position, I think many modern drives just feed the windins with the right waveforms and the rotor starts spinning. So yes, you need drvier electroncis, but it's not hard to design. Actually, most modern-ish FDD motrs are similar to the HDD motors. I guess the big difference practically is that in many cases (although certainly nor all), the motor and its control electronics is on a separate PCB in a dloppy drive so you can extract the whole model and have soemthign that just needs power and an enable signal to get it to spin. -tony

Probably :)

No, I'm with you on this one. I see no humour in it at all. I spend far too much of my time fixing 'natural' fuults to want to have soemthing liek this around... -tony

A number of HP devices have a BNC conenctor as a 5V power output to ru na logic probe or external add-ons. My HP1630D logic analyser has one o nthe bnck pannel to power probe interedaces. The 59403 HPIB-RS232 interface has one on the back to pwoer a logic probe for testing, my Multiprogramemr has one inside the front door for a similar purpose. I am told some HP logic probles had a BNC plug on the cable specifically to plug into such a connector. And of course BNC connectors have been used ro the RF output of smallish radio transmitters. I suspect applyig na few watts of RF to an ethernet cable could be 'interesting'. Moral : Do not connect random BNCs together... -tony

I beleive that's actually impossible. RJ45 implies not only the conencotr (8p8c 'modular' but also the wiring/signals. 10baseT and 100baseT ethernet connectors are not strictly RJ45s, and anythign with mains on it isn't either... -tony

Geoffrey Reed wrote: and the jack. If it doesn't have isolation between the electronics and the receptacle, it isn't actually 10BASE-T or 100BASE-T. Personally I've never seen one that didn't have isolation. That's a recipe for disaster. Note that sometimes the isolation is built into the jack.

THat would do suprisignly little damage I think. Ethernet conencotrs are isolated from the rest of the machine (the traceiver chip is on the conencotr side of the isolation barrier), so applyging mains to the BNC connector (or indeed the 8p8c [1] of twisted-pair ethernet) will kil lthe transciver chip, possibly the isolation transformern and DC-DC converter, but will dont get much further. [1] It's not RJ45 damnit! Applying mains to na RS23 2connecotr could end up blowing out chips all over the machine.... And while both D-seires nad BNC connectors are rated for votlages bove mains, I do have a problem with having one side of the mains connected ot the metal shell of a BNC plug. -tony

On Nov 11, 2011, at 7:44 PM, Toby Thain wrote: I know my DELQA cable kit has a fuse in it, but I think it's for the AUI-supplied power instead of any signal lines. - Dave

That's rather different, though; that fuse, if I recall correctly, is in the +12V power feed to the DA15 AUI connector, not something that would be in-circuit for applying high voltage to thinnet or twisted-pair connections. Of course, if you do something similar but for DA15, you could blow it - and, quite likely, various other pieces of the machine that use the same power feed. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

On Nov 11, 2011, at 3:05 PM, Tony Duell wrote: That does assume the circuit is designed correctly. I think the original BOFH "joke" was "Let's see if that 10KV isolation really works!" I've definitely seen enough circuits where questionable things were done to the magnetic (mostly bypassing it "just a little" to make it work with some bad engineering elsewhere) that I'd worry. And, of course, the fun bit about BNC was supposed to be that since it's all the same physical media, you'd be testing the entire network's isolation ability. - Dave

No...but the transformer is not going to pass very much power at mains frequency; it's designed for much higher frequencies. Also, "let's test that isolation" calls for different wiring than "let's apply mains power across the output of the transformer". /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

I wrote: Mouse wrote: It doesn't take any power to speak of to destroy MOS chips. It only takes a voltage a little above the abs max Vdd rating, at a few mA. If you put mains across the Ethernet transformer, it will destroy the transformer quickly, but not nearly quickly enough to prevent damage to the stuff on the other side.

For the record: Mains power applied to an RJ11 connector plugged into a netgear 10/100 PCI ethernet card produced pretty, multicolored sparks and causes the card to physically jump. and the middle of the cable to blow apart half a second after due to poor construction of the cable.... Version 2.0 will have better insulation at the cable splice point! ..... IDE harddrives provide the best light show, (blow out at least 3 chips). SCSI harddrive just provided a single regulator explosion. DVD-ROM drive had a big shower of sparks, but that was all it had. ..... beer, hackerspace, saturday night. What more could you ask for? On Fri, Nov 11, 2011 at 3:05 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote: -- Gary G. Sparkes Jr. KB3HAG

On Nov 11, 2011, at 1:34 AM, "Alexandre Souza - Listas" <pu1bzz.listas at gmail.com> wrote: ROFL!!!!!! -- Dave McGuire New Kensington, PA