[cctalk] Re: FWIW CD & DVD demagnitizitation [was: Double Density 3.5" Floppy Disks]
> First, in general, there are so many apparent reviews of so many products, it > is hard to believe they are all scams. How can there be enough fools to buy > enough of those products to have that many different ones? I see you're new to the intersection of the audiophile world and online selling :P Pretty much all of that stuff is "dubious at best" nonsense. We used to get print magazines/catalogs for that junk at ITI Audio/Sontec. Demagnetizing CDs and DVDs is up there with the special offbrand Sharpie marker for coloring the edges of the disc to reduce...whatever it didn't actually reduce. Thanks, Jonathan
[cctalk] Re: Drum memory on pdp11's? Wikipedia thinks so....
> Well, I can submit a correction, but does anyone remember /dev/drum? I > don't recall that in V6m or V7 Unix, I guess I could fire one of them up > and see There's at least references to /dev/drum in 2.11BSD, I forget if it was in the docs or actually important stuff in the source. I don't have my PDP-11/83 set up at the moment to check! Thanks, Jonathan
[cctalk] Re: PDP-11 thingy. What is it?
> 1. I have read that the card and the drives were compatible with the dec rx02 > drives. Why would the CRDS even bother to redesign a card where DEC had > perfectly good working ones? Anyone know if there is any value in keeping the > FC-202 or just keep with the DEC cards? A lot of the third-party controllers could talk to Shugart-style 8" floppy drives. They can also usually *format* the diskettes, which the RX01/RX02 systems from DEC can't do -- you have to use preformatted media. This isn't a *huge* deal since RX01 is just IBM 3740 and you can format it on CP/M boxes, with ImageDisk, etc. There's an XXDP utility to upconvert RX01 media to RX02, which is M2FM and very few things can work with it. Apparently a lot of small shops kept a CP/M box just for the task, the Alspa ACI-2 I had was supposedly used like that. > 2. Any idea on that other card? > https://w2hx.com/?prefix=x/What-Is-It/PDP-11-Thing/Board1/ Looks like a non-DEC Qniverter -- QBus to Unibus converter. If that's what it is, you'd plug your Unibus cable into that pair of connectors on top and run it to whatever Unibus device you were wanting to talk to, potentially another backplane full of Unibus stuff. Commonish upgrade on e.g. CNC machines that were originally controlled by a PDP-11/05 or something in one Unibus chassis, with another Unibus chassis full of machine-specific cards. Thanks, Jonathan
[cctalk] Re: typical IC kits on Amazon and elsewhere
> Been lurking for a while, but this topic hits true with some recent > experiences. I would not hesitate to buy most common digital ICs on Amazon > or ebay I mean we had to stop buying 7400 series from Jameco over counterfeits, so it's definitely a problem for jellybean parts too. We had so many reject 74F573 latches go out in XT-IDE kits we just scrapped the remaining Jameco-provided inventory. We also started having issues with 28C64B EEPROMs from them, obvious relabels that wouldn't program with the Atmel SDP algorithm -- that's actually why they started shipping pre-programmed in kits! Real shame, I've bought from Jameco since I was a kid, they'd actually sell to Just Some Kid :P Personally I'm not willing to save the relatively small amount of money on TTL by buying from random sources. It's especially infuriating when you're building something for the first time (prototypes, someone else's project you've never put together, etc.) and it turns out to be a dead 25 cent chip. Thanks, Jonathan
[cctalk] Re: typical IC kits on Amazon and elsewhere
> Standard TTL 74XXX is drying up rather quickly. Futurlec still has some > TTL but 7404s are all gone. Even LS is hard to find. Ours comes from Mouser, between two part #s they have over 7,000 74LS04s in DIP packaging in stock. Didn't check ACT, HCT, or ALS. I don't think we've had a 7400 series part that we couldn't just order off Mouser in recent history, and we're usually buying QTY 100. Thanks, Jonathan
[cctalk] Re: WTB: Cromemco System Zero
> I had no idea they made a System Zero. I have a System One FWIW. Apparently a lot of folks, even those actively hacking on S-100 stuff, don't know about the System Zero! I've had a number of folks say as much. It's definitely a real product, I had a purchase lined up for one a few years ago, but the seller stopped responding to emails (I suspect someone else came in and bought everything). That seller had worked on integrating Cromemco hardware for industrial control usage, and had used a bunch of the System Zero boxes in his time for the purpose. The SCC with 3K Control BASIC plus whatever additional memory or I/O made for a compact little control box with industrial strength design, apparently. Thanks, Jonathan
[cctalk] WTB: Cromemco System Zero
All, I'm looking for a Cromemco System Zero, doesn't matter if it's empty or not. Please contact me off-list if you have one to sell/trade or know of one! Thanks, Jonathan
[cctalk] Semi-OT: MAX180 Evaluation Kit ROM/Diskette Image
All, I'm looking for an image of the ROM or companion diskette for the Maxim MAX180 Evaluation Kit (MAX180EVKIT). I've got one that has a custom application ROM in it. Thanks, Jonathan
[cctalk] Re: ADM3a screen rot.
> This apparently is true of some capacitors as well, I'm not sure which types. It is true of all capacitors (CRTs are intentional capacitors, after all) designed for and subjected to sufficiently high voltage. It's referred to as dielectric absorption, and is why HV caps ship from the factory with the leads shorted. I have a 4.7 uF tens-of-kV capacitor in the shop for reasons. The shorting jumper got knocked off once while moving stuff past it, and I noticed it the next day. By that point, it had accumulated enough charge to register over 200V on a Simpson 260 VOM (not a high impedance meter). I don't know if that was accumulated static charge or from dielectric absorption. Thanks, Jonathan
[cctalk] Re: WWVB
> I agree with Don on the interference. We have a very high noise floor > here in Toronto as well as being on the fringe IIRC there's something on-frequency in England that often swamps WWVB on the northeastern part of North America, too! Thanks, Jonathan
[cctalk] Re: WWVB
Bill, If it's an older clock it's probably tripping over a timecode transmission format/modulation change. I forget the exact details but changes were required to my old 8085-based Spectracom receiver. Thanks, Jonathan On Sunday, January 14th, 2024 at 14:49, Bill Gunshannon via cctalk wrote: > > > > This is kind computer related but maybe more ham radio related > but I figure if anywhere, here is the place to find an answer. > > I have a SkyScan ATOMIC CLOCK. > It is supposed to get its time from WWVB. > The antenna icon that is supposed to mean it is receiving > WWVB is on. > > Your probably wondering why I keep saying "supposed to". > The clock is always wrong. Slow by about 2 minutes. > > Is there a known problem with WWVB? > > bill
[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...
> Next step will be trying the same on my UltraBook (DS1643 instead of DS1553 > on the UltraBook IIi). But need to Xray that one first before attaching a new > battery. I have a DS1643 replacement prototype if you're interested. Thanks, Jonathan
[cctalk] Re: Soviet tube/transistor/IC spec source
Very cool, thanks for sharing! I didn't know such a tabulation existed! Thanks, Jonathan --- Original Message --- On Monday, October 2nd, 2023 at 13:12, Shoppa, Tim via cctalk wrote: > > > For those working with ex-Soviet equipment from the 60’s and 70’s here’s a > remarkable resource: > https://www.govinfo.gov/content/pkg/GOVPUB-C13-6925b02fb6dcaa88935be001eb551b4c/pdf/GOVPUB-C13-6925b02fb6dcaa88935be001eb551b4c.pdf > > I am astonished that I found it in this in the US National Bureau of > Standards (today NIST) archives > > Tim N3QE
[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...
Booted the SPARCbook 3, its battery is in fact dead, and aside from taking a little longer to come up (totally expected) it's fine. Thanks, Jonathan --- Original Message --- On Thursday, September 28th, 2023 at 07:41, Jonathan Chapman via cctalk wrote: > > > Yet we have a few datapoints showing that a dead NVRAM/RTC still boot > UltraBooks just fine! As I said, I personally confirmed with my UltraBook > IIe. Pretty sure the NVRAM is dead in my SPARCbook too, I can confirm that > today. > > Thanks, > Jonathan > > --- Original Message --- > On Thursday, September 28th, 2023 at 05:08, erik--- via cctalk > cctalk@classiccmp.org wrote: > > > > > > Hmmm, not sure on that one actually. So it does not boot up at all? > > > > Yes - exactly! > > > > > In the desktop Sun workstations and e.g. the Tadpole SparcBook, a lost > > > NVRAM at least > > > shows the firmware prompt on the screen (no HOSTID and no ethernet MAC). > > > > Yes, that is different in the UltraBooks. There is very likely some deep > > hardware specific stuff in the NVRAM. In Tafpoles, SparcStations and > > similar (I have some of them) there is NEVER a sticker with the serial > > numer on the NVRAM, but in the UltraBooks there is. That is also > > anindication for me, that the NVRAM is paired to the hardware. > > > > > situation is not as severe as with the UltraBooks where the screen > > > remains black/dark and > > > no interaction is possible! > > > > Exactly - and therefore I fear, that all the UltraBooks will die, once the > > relevant bytes get lost. Mine operated for some years with the "Invalid > > NVRAM" message until I attached the battery to the NVRAM and herein > > completely erased it because it was completely without power for some time > > (old battery was down to 0.426V).
[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...
Yet we have a few datapoints showing that a dead NVRAM/RTC still boot UltraBooks just fine! As I said, I personally confirmed with my UltraBook IIe. Pretty sure the NVRAM is dead in my SPARCbook too, I can confirm that today. Thanks, Jonathan --- Original Message --- On Thursday, September 28th, 2023 at 05:08, erik--- via cctalk wrote: > > > > Hmmm, not sure on that one actually. So it does not boot up at all? > > > Yes - exactly! > > > In the desktop Sun workstations and e.g. the Tadpole SparcBook, a lost > > NVRAM at least > > shows the firmware prompt on the screen (no HOSTID and no ethernet MAC). > > > Yes, that is different in the UltraBooks. There is very likely some deep > hardware specific stuff in the NVRAM. In Tafpoles, SparcStations and similar > (I have some of them) there is NEVER a sticker with the serial numer on the > NVRAM, but in the UltraBooks there is. That is also anindication for me, that > the NVRAM is paired to the hardware. > > > situation is not as severe as with the UltraBooks where the screen remains > > black/dark and > > no interaction is possible! > > > Exactly - and therefore I fear, that all the UltraBooks will die, once the > relevant bytes get lost. Mine operated for some years with the "Invalid > NVRAM" message until I attached the battery to the NVRAM and herein > completely erased it because it was completely without power for some time > (old battery was down to 0.426V).
[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...
> Hi Jonathan, thanks for your thoughs. I am still using the same NVRAM, just > with external battery attached, so no Chineese counterfeit. > My hypothesis is: With the battery losing voltage, some bits flip first. They > cause the error message you see and values get set to proper values. But > there are some bytes which must not flip because they determine e.g. the type > of graphics, processor, speed, RAM timing etc. If one of these bits flips > first, than one is lost because the machine does not reach the OpenBoot > firmware because it tries to test non-existing hardware etc. etc. I wouldn't think that's possible, the small portion of NVRAM used to set parameters is checksummed, so it's unlikely a random combination would also result in a correct checksum. Still, to rule that out, try blanking the NVRAM by writing all zeroes to it. You may be able to do that with something like a TL866+ and a shim socket -- don't just plug the DS1553 right in, as it's got two output pins that may cause a conflict! Thanks, Jonathan
[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...
> Interesting - did you youse some modern technology for > doing that? Modern "special sauce" replacements from Dallas/Maxim/Analog/etc., plus a fast, low-power SRAM, all packaged on a circuit board with Batten & Allen DIP leadframe pins, like this: https://users.glitchwrks.com/~glitch/2018/03/17/gw-1244-1 (note that the Phantom RTC chip used in that is *not* what would be needed for Sun-style NVRAMs) Thanks, Jonathan
[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...
> Speaking of dumping... > > Is it possible to read a Dallas DS1643 in programmer? That's what's in my > Ultrabook. I just tried with a Topmax II that supports it and I get all > zeros. :( You probably need to make a shim socket and pull pin 26 to VCC (pin 28), then read it as a DS1225. I'd also pull pin 27 (*WE) to VCC to avoid errant writes. Thanks, Jonathan
[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...
/me hears mention of dead NVRAMs and materializes Pulled out my UltraBook IIe today, it's fine with a dead NVRAM, just gives you the usual "IDPROM contents are invalid" message you see on Suns. If I'd have to guess, based on past experience, you likely have a counterfeit DS1553W or you ordered the DS1553 without the W suffix. The W means 3.3V part. On a 3.3V system, the DS1553 5V part will never release write lock-out; furthermore, the DS1553 has a power-on reset comparator and will never de-assert reset either! I don't know if the UltraBooks use this reset output, but if I were designing a system and using the DS1553/W, I certainly would. A missing DS1742W in a SGI Tezro stops it dead, as does a DS1742 5V part (W suffix is, again, 3.3V). Part of what took so long on my designing a replacement for the DS1742W was the sacrificial modules that were sent to me were...wait for it...Chinese counterfeits! The part numbers from the dissected modules were all 5V parts! Now the good news is, I can probably make replacements for the DS1553W. I already have a prototype replacement for the DS1643, some customer must've needed it for a one-off as I've never run more, but that should already be a solved problem. I have one or two GW-1643-1 prototypes on hand for testing. Thanks, Jonathan
[cctalk] Re: FTGH: (3) Qualstar 1260 9 track tape drives pertec interface
> Do you know of a source for drivers and software for the PC environment > for this equipment? I was recently given a 1054 which is supposedly the > same system with a SCSI interface. I've yet to find anything online. > Any suggestions would be most appreciated! The version with SCSI (it's a SCSI to Pertec bridge inside) works fine under Linux with the usual SCSI tape driver and `mt`. Thanks, Jonathan
[cctalk] Re: Silly question about S-100 and video monitors
> Other than graphics (and maybe some special function keys for an application > on a keyboard), why would an S-100 builder in those days opt to buy a video > card instead of a terminal? Primarily cost I'm led to believe. There were also games that took advantage of primitive graphics characters. Thanks, Jonathan
[cctalk] Re: Polymorphic Systems Poly88
Marvin, You and I had talked about reproductions of some of the Poly 88 stuff at VCF MW in I think 2018. We're currently working on that project, Connor Krukosky recently spent a week down here capturing dimensions on both the old and new style cases and covers! We're currently nailing down the final details there before sending them off for a prototype manufacturing run. I am planning on being at VCF MW again this year, if you want to bring some of your original Poly stuff, we can help in getting docs scanned, diskettes imaged, etc. Thanks, Jonathan --- Original Message --- On Wednesday, August 9th, 2023 at 15:16, Marvin Johnston via cctalk wrote: > > > FWIW and as some of you might know, Polymorphic was manufactured here in > Santa Barbara (also Lobo Drives/Systems, and Street Electronics.) After > Poly had gone out of business, a friend of mine ended up getting all (or > most) of the remaining Poly documentation and most of the remaining > hardware from the person who owned the Polymorphic remains. After he had > sold off some of that "stash", he gave the remaining stuff to me. I > spent a week or so taking the remaining original masters documentation > and putting it in a filing cabinet. That stuff included approximately > 200 S-100 boards in various states of being built and maybe up to ten > thousand (WAG) 1/4" and 8" disks of stuff that was being worked on at > Poly when they shut down. > > On my to-do list is to scan the remaining documentation (about a four > drawer filing cabinet) as well putting together the remaining Poly88s > (four- six) and other boards. I had planned on bringing some of that > "stuff" to VCFMW, but found out last night the exhibit area was filled. > So at this point, I don't know if I will be attending or not. > > I am more concerned with getting the documentation scanned and archived > and will most likely end up buying a high speed double sided scanner. So > this is just a heads up that a lot (most?) of the original Polymorphic > documentation does still exist. Years ago, some highly uninformed > individual said this could not be original since there were no graphics > in the Circa early 1970 docs. He was wrong about this not being original > documentation!!! I also tried to keep any marked diskettes with the > docs. Those disks were primarily system disks. And those disks NEED to > be backed up before they degrade to the point they would be difficult to > read. > > FWIW, I would have liked to get this stuff scanned, etc but at that > time, I didn't have enough money to pay attention let alone buy a > scanner to scan this stuff :). > > Marvin
[cctalk] Re: 50 pins in three rows
> Anyone seen those before, and is it actually SCSI, or is it something else? Common on old Sun SCSI stuff, it's a DD-50. Could be something else, but they were indeed used for SCSI termination. Thanks, Jonathan
[cctalk] Re: VCF and System Source Computer Museum swap meet this weekend
> Is that somewhere in Maryland? Yeah, Cockeysville, just outside Baltimore off I-83. Thanks, Jonathan
[cctalk] Re: VCF and System Source Computer Museum swap meet this weekend
I'm going, there's going to be a fair bit of Ohio Scientific hacking going on this weekend. We're going to try and get my CD-23 hard disk system up and going and pull data off it (14" Shugart SA-4008) Thanks, Jonathan --- Original Message --- On Tuesday, July 18th, 2023 at 19:56, Mark G Thomas via cctalk wrote: > > > Hi, > > I am curious if anyone here might be planning on attending. > > https://museum.syssrc.com/artifact/events/3000/ > > The Vintage Computer Federation and the System Source Computer Museum are > hosting a vintage computer repair workshop on Saturday July 22nd and > Sunday July 23rd 2023 > ... > > Mark > > -- > Mark G. Thomas m...@misty.com, KC3DRE
[cctalk] Re: 1-click exploits was Re: BEWARE: Phishing
> It helps if you're running a version of *nixand not fenestrae. Helps, but is not the near cure-all it was at one point, especially for the larger/more popular distros! Thanks, Jonathan
[cctalk] Re: VT100: Datasheet for Intel 8228
HLDA should be deasserted, that puts the processor in a DMA mode where it releases all the control signals. I/O W is asserted low when OUT is high and the low WR pulse comes along. It's both status and timing, coming out of the 8228. You would probably do well seeing if MEMR and MEMW are asserting. If the program is running off due to e.g. bad RAM, ROM bitrot, etc. you may never see the I/O lines assert. Thanks, Jonathan --- Original Message --- On Sunday, July 9th, 2023 at 12:12, Rob Jarratt via cctalk wrote: > > > Actually I have just found a more detailed description in the Intel 8080 > Microcomputer Systems Users Manual 1975, but it still doesn't tell me > exactly how it works. It isn't completely clear to me if it needs HLDA to be > asserted for I/O W to be asserted. > > > -Original Message- > > From: Rob Jarratt via cctalk cctalk@classiccmp.org > > Sent: Sunday, July 9, 2023 4:39 PM > > To: General Discussion: On-Topic and Off-Topic Posts > > cctalk@classiccmp.org > > Cc: Rob Jarratt robert.jarr...@ntlworld.com > > Subject: [cctalk] VT100: Datasheet for Intel 8228 > > > > Hello, > > > > I have a non-functioning VT100. I think I may have isolated the problem to > > an > > > Intel 8228 chip (or 88228, the schematic says 8228, the part is marked > > 88228C). Certainly, the part gets a bit hot and it doesn't seem to be > > outputting anything on the I/O W pin (pin 27) despite activity on STSTB > > (pin > > > 1), DBIN (pin 4) and WR (Pin 3). There is no activity on the HLDA input > > though, but I am not sure if that is required because I think the firmware > > is > > > just trying to send its status to the keyboard LEDs. > > > > I can find a brief datasheet for the 8228 but it doesn't tell me the logic > > for > > > producing the I/O W signal, so I am not sure if it is behaving as it > > should. > > > Does anyone have more comprehensive information on how the 8228 is > > supposed to work? > > > > I have dumped the ROMs and been able to capture the ROM reads and they > > match the disassembled code, so I think the 8080 CPU itself is working. > > > > Thanks > > > > Rob
[cctalk] Re: Need AUI cable
> Not necessarily a DEC thing. TEMPEST PC's (and other TEMPEST boxes like > fiber > > ethernet transceivers) also had screw connectors rather than the spring > clip ones. It's semi-common on random old stuff, yeah. I've got a Cisco IGS that uses jackscrews, and have had a pretty good number of ISA Ethernet boards that use either jackscrews in the usual D-SUB location, or the really wide-set ones that like two transceivers fit. For the Cisco IGS, there's a part # for an adapter cable with jackscrews on the router end and slide latches on the transceiver end, but they rarely show up. I have one or two for it, but have not found more. Protip: Ungermann-Bass made jackscrew transceivers both ways (wide and standard) and they're usually cheap. Thanks, Jonathan
[cctalk] Re: Need AUI cable
> There is no real equivalent of an 'AUI null modem cable' (should that > be 'null transceiver cable'?) > > If you want to link 2 computer-type ports together you need the > equiavelent of 2 transceivers. This (or devices like it) is probably the only single-piece two station "null modem adapter": https://i.imgur.com/qiMh9Tc.jpg It's a twin tap, with two AUI connectors. If you drop an intrusive BNC or N tap in there and terminate it, it'd act like a "null modem" for AUI. > If you want to link 2 transceivers together on the AUI side then > that's a network bridge. Even a basc one is quite a lot of > electronics. DEC's full wirespeed bridge was supposedly considered something of an engineering miracle at the time and occupies 2U of rack space! Thanks, Jonathan
[cctalk] Re: Need AUI cable
> There is also DD, though I've never seen one in the wild. Old SCSI uses DD-50. I've also seen it used on Pertec tape controllers and multiport serial cards. Thanks, Jonathan
[cctalk] Re: Need AUI cable
> For a few inches, which would be enough here I think, I've used an IDC > DA15 plug and socket crimped onto the normal ribbon cable. Technically > it's wrong but the reflections on that length of cable won't matter. That's how Sun VME Ethernet boards are set up, the board itself is way back near the VME connectors and small (or a Multibus in a converter, and small). Can't be too bad if Sun did it on serious business workstations, right?! Thanks, Jonathan
[cctalk] Re: Need AUI cable
These are my go-to for short ones: https://www.ebay.com/itm/233295839501 Not affiliated with seller, just a satisfied customer. Thanks, Jonathan --- Original Message --- On Tuesday, June 27th, 2023 at 21:16, Chris Zach via cctalk wrote: > > > Anyone in MD got an AUI cable (few feet long) I can steal so I don't > have to remove the bolts from the Pro/380's Ethernet socket or the pins > on my 10bt ethernet MAU? > > Friendly note: If you try to boot a Pro/380 running POS 3.2 with Decnet > installed and don't have the loopback plug the system will crash hard > with a numeric error on the display. Noted. > > CZ
[cctalk] Re: Gb Ethernet and 10Mb links
> I believe the 10Gb standard specifically prohibits autonegotiation, so > 10G should not drop down to 1G or 100Mb/s. It drops down to 1gig just fine, at least on everything I've tested. This is of course over copper, not optical. Thanks, Jonathan
[cctalk] Re: Gb Ethernet and 10Mb links
Best thing to do is keep an old 10mbit switch or hub around with 100mbit or gigabit uplink. Second best thing is to have a router that will talk 10mbit half duplex. I've also found some poorly behaved stuff that won't autonegotiate duplex even with older switches, like my 3Com SuperStack II. Asante SCSI Ethernet adapters come to mind. Had to set the duplex manually on the switch. Along those lines, 10gig copper interfaces often don't want to talk to 100mbit ports! Found that out when we had a switch fail and stuck an older 10/100 switch in just to get back up and running. Thanks, Jonathan --- Original Message --- On Sunday, May 28th, 2023 at 13:46, Craig Ruff via cctalk wrote: > > > FYI: The Ethernet standards dropped support for half duplex connections a few > years back, so that if you have something that depends on half duplex links a > recent Ethernet switch might not support it.
[cctalk] Re: Altair 8800 question
Everyone lost the metal strip! It's sandwiched in between the trim of the outer case and the dress panel. Some folks stuck it to the dress panel with glue, double-sided tape, etc. Those are usually the machines which still have the metal strip. Thanks, Jonathan --- Original Message --- On Tuesday, May 9th, 2023 at 14:08, W2HX via cctalk wrote: > > > I see some altairs have a metal escutcheon on the bottom with the stylized > words "MITS ALTAIR 8800 COMPUTER" whereas others, the front panel is just the > dark faceplate top to bottom. What is the difference? Would one have been a > kit and the other sold fully assembled? Or maybe later units vs earlier units? > > > 73 Eugene W2HX > Check out my Youtube Channel: https://www.youtube.com/@w2hx/videos
[cctalk] Re: Knockoffs, was: Low cost logic analyzer
> Make of that what you will, but if that isn't just a slander, that's the > guy upon whose legacy everyone is relying. Everyone knows (or ought to, at this point) RMS is a weird guy and at best makes some seriously questionable life choices and misinformed public statements. There's a reason he was forcibly removed from his position at MIT. I've met him in person, he's a weird guy. Both GNU and FSF have grown much larger than RMS. Thanks, Jonathan
[cctalk] Re: Knockoffs, was: Low cost logic analyzer
> FSF does not enforce anything. I repeatedly begged for help with Desktop > CYBER which was GPL licensed and they did not even bother to reply. I'm told by a friend at Red Hat that RH/IBM has a department for that kind of thing and can/will provide legal help for outside projects. Thanks, Jonathan
[cctalk] Re: Knockoffs, was: Low cost logic analyzer
> If you posted your design as Open Source, someone else producing it isn't a > knockoff, it's the system working as intended. What is it when the design is open source, but they're not complying with the terms of the license? That's what really bugs me, the "cost" of producing your own from one of our designs is attribution and releasing your design under the same or a compatible license, but apparently that's too much to ask. Thanks, Jonathan
[cctalk] Re: Knockoffs, was: Low cost logic analyzer
> But, as some who worked > to bring a product to market only to see people on forums say "Skip > buying it from Jim for , you can build the same thing by yourself > for $ from AliExpress parts or buy this eBay knockoff for 2X$", I will > admit that is somewhat infuriating. If the hobby community is not > willing to pay a bit of premium to support those who bring out the > products that benefit the community, the designers will get disgusted > and leave. Agree 100%. We stopped running XT-IDEs for a while due to the proliferation of knockoffs and the total indifference of a good portion of the community -- some folks even get hostile when you suggest they maybe not buy knockoffs that can't even abide by the terms of the open-source project license! I'd designed a universal "bolts to any existing XT-IDE and doesn't eat a slot" CF adapter that never got run. After posting a development picture of the prototype, one of the knockoff folks ripped the design off before I had even received my quote from Keystone for the custom ISA brackets. No way was I going to spend on a run of 500x custom brackets when someone was already ripping off the idea. There are other things that we've chosen not to run for the same basic reason, and others that won't get open sourced. > Thus, I'd say if a Saleae is something to pursue, try to buy > one from them, to support their awesome GUI, and then drop by eBay and > grab 2 or 4 of the knockoffs to put in your toolbox or travel debugging > rucksack. I'll go further and say don't buy knockoffs, period. It's nice to support the designers in some capacity, but buying knockoffs fuels the ecosystem that creates knockoffs. With our stuff, it's never been that a single knockoff operation eats our lunch, it's that there's a zillion of them that run maybe 100 boards and disappear. Death by a thousand cuts. They charge $1-5 less while running the cheapest possible boards, stuffing with salvaged chips, etc. Meanwhile, we're having to pay for runs of boards with hard gold plating and buy genuine parts from Mouser. Thanks, Jonathan
[cctalk] Re: Low cost logic analyzer
> On HP: yes, perhaps. I used one of those back at DEC, in the mid 1980s. Nice > machine, but my suspicion is that I'd run into the small memory problem again > that plagues me with the Philips/Fluke analyzer I use right now. We use several HP analyzers around here, all from the 80s. Even the "small" ones are 72 channel and more than sufficient for all your old computer needs. The big ones have Ethernet and will talk X11 across the network, which is super handy. The older models are serial-only, but can print to a ThinkJet emulator running on a PC. That's how I made e.g. this capture image: http://users.glitchwrks.com/~glitch/images/xtide/xt_ide_rev4/read_delay.gif Before getting my first HP 1650, I had an older Sony/Tektronix that suffered from the "not deep enough capture memory" issue. Haven't run into that with the HPs yet, especially the big HP 16500 series. I've found that if I'm running out of memory depth, I'm probably not hooked up right. FWIW, I've ran into two hobbyists who were persuaded to buy used HP gear after their Chinese knockoff Siglent analyzers started *driving* some of the channels. Thanks, Jonathan
[cctalk] P Surplus in Kingston, NY
All, I went to find a page about P Surplus to link to a friend who'd never been there, and this was today's top result: https://www.dailyfreeman.com/2023/02/19/pt-surplus-in-kingston-struggles-as-owners-battle-illnesses-mounting-bills/ Apparently Mr. Smythe is having hard times with his business. For those in or near the Hudson Valley, this place is definitely worth checking out! They have a ton of industrial surplus, including a lot of IBM castoffs. Pretty good shop for potential vintage computer stuff. Last time I was there (early February 2023) there was a box of neon lamp IBM front panels off what I'd guess was tabulating equipment. I always find good stuff in their board scrap, though the edge connectors are sometimes sheared off. There seem to always be earlier IBM Thinkpads there, Pentium 3 and earlier are common finds. They also have lots of mechanical hardware, metals raw material, 80/20 extrusion for dirt cheap, etc. Thanks, Jonathan
[cctalk] Re: ZFS, was [... GreaseWeazle ..]
> So, what else do you guys use, to make sure your data is safe for the > years to come? ZFS and redundant copies of important stuff, plus backups on media that's likely to be readable in 10 years (meaning the drives must still work/be available, too!) Anything that's appropriate to have on a public Github repository should go to one. Thanks, Jonathan
[cctalk] Re: Aging of unused CD-R media
> I find myself wondering, how well does CD-R and DVD-R media that hasn’t been > used age? Anecdotal, but I have some Fuji blanks from the 90s that still burn just fine (works great on old drives that hate modern "see-through" media). The DVD-Rs I have were bought by my parents in the mid-2000s when they thought they were really going to move all their VHS to DVD The Hard Way, they bought like 500 Verbatim-branded blanks and used maybe 20. I have a few spindles of Verbatim archival CD-Rs and DVD-Rs, which are mostly used for sending customers backups of data. Those were bought some time before 2015 and work fine. One would sort of expect that, though :P I also threw out most of a spindle of IIRC Memorex that came in some lot of something else that looked like it was maybe 5 or 6 years old. Ended up with some still-wrapped Sony blanks from the 90s (I think they were rated for 2x burning!) that were totally eaten up, something attacked the metal layer. They came with a bunch of other CDs (burned and pressed) that were all fine, so I assume it wasn't storage conditions. Thanks, Jonathan
[cctalk] WTB: Kinetics/Shiva FastPath 4 or 5
All, I've been looking for a Kinetics or Shiva FastPath 4 or 5 for a while, without luck. Don't know why I didn't think to ask on the various lists! If anyone has one they'd like to part with, let me know off-list. Thanks, Jonathan
[cctalk] Re: Xerox 820II U07 Power Supply magic smoke....
If the PSU requires too much hacking, you may just want to replace with a modern Mean-Well switcher or two. The Aztec supplies used in those Xerox enclosures are OK but nothing stellar. I recapped mine (it also showed signs of electrolytic leakage) and it did work so I kept it, but if it'd had issues I'd have junked it. Thanks, Jonathan --- Original Message --- On Thursday, October 13th, 2022 at 09:32, D. Resor via cctalk wrote: > > > I do understand that these are common film capacitor types. There is one more > smaller .10ufa RIFA branded capacitor hiding near the center of the PWB. > > A couple reasons I'd like to have a circuit diagram is to know what the RIFA > capacitors purpose are. The other is, a couple of the electrolytic capacitor > are double covered with what appears to be rubbery heat shrink tubing, > therefore I cannot read what their value are. > > One of these two electrolytic capacitor appears to have a dried substance > around the top. The over-pressure venting cuts in the top of these two > capacitors are not split. At this point I cannot tell if it is dried > electrolyte, cement to hold the sleeve on, or possibly paper. > > Looking at these two again, it definitely could be dried electrolyte. I have > seen it creep out and up into strange places. > > https://www.dropbox.com/s/18hzfdqe96vmgsr/electrolytics.jpg?dl=0 > > Seems someone was in hurry on the day this PS was tested. I cannot make out > date, is it 1983? > > https://www.dropbox.com/s/zlt2ocpqulil13j/pssticker.jpg?dl=0 > > What type are the diodes, their rating etc.? I seem to remember this type > with a black band were rated at 3 amps, but that's all I remember. > > The TO-3 transistor/regulator has no P/N silkscreened on it. > > Having a circuit diagram helps to cover many bases. Apparently it's an Astec > AA12070. > > Placed the PS board back in the garage to continue airing out! > > Don Resor > > > > > > -Original Message- > From: Joshua Rice via cctalk cctalk@classiccmp.org > > Sent: Thursday, October 13, 2022 4:43 AM > To: General Discussion: On-Topic and Off-Topic Posts cctalk@classiccmp.org > > Cc: Joshua Rice ric...@btinternet.com > > Subject: [cctalk] Re: Xerox 820II U07 Power Supply magic smoke > > > You shouldn't need a schematic. These thin film caps are a common failure > mode on a multitude of PSUs. Just replace like for like. Thin film X and X2 > rated caps are easily found from your favorite electronics part retailer. > > If it's gold and got RIFA on it, replace it, though. Just because it hasn't > popped, doesn't mean it wont pop in the near future. > > I've learned now, to always check every PSU or other mains-powered vintage > equipment for these little stinkbombs. If they're present, i'll always > replace. > > Cheers, Josh > > -- Original Message -- > From: "D. Resor via cctalk" cctalk@classiccmp.org > > To: "Classic Computer Mailing List" cctalk@classiccmp.org > > Cc: "D. Resor" organlis...@sonic.net > > Sent: Thursday, 13 Oct, 2022 At 12:24 > Subject: [cctalk] Xerox 820II U07 Power Supply magic smoke > Where might I find a schematic diagram for the Xerox U07 8" FDD,HDD expansion > cabinet for the 820II, and/or the 105P80450 power supply? > The Xerox Professional Computer Technical Reference Manual I downloaded from > bitsavers.org doesn't seem to have those particular schematic diagrams. > For your enjoyment the part which smoked. > https://www.dropbox.com/s/al9kx3yw9ypwp89/Xerox105p80450.jpg?dl=0 > https://www.dropbox.com/s/al9kx3yw9ypwp89/Xerox105p80450.jpg?dl=0 > > I certainly am glad I have the lid off while testing. Unfortunately these > capacitors which appear to be film type were hidden from view. > The fuse didn't blow, but that .22uf 250v capacitor certainly stunk up the > house. It smelled like burnt popcorn, plastic and the bottom of a coffee pot > which has boiled dry, yech! > I know that if I had pulled the power supply board first I might have seen > the physical cracks in these boxed capacitors. > Wasn't it Marc V. that said in one of his videos, you don't need to shotgun > them all! Oi, lol It's when things like this happen that I most always worry > about not going over vintage equipment fine tooth comb. > Don Resor > > >
[cctalk] Re: Xerox 820II U07 Power Supply magic smoke....
> If it's gold and got RIFA on it, replace it, though. - snip - > I've learned now, to always check every PSU or other mains-powered > vintage equipment for these little stinkbombs. If they're present, i'll > always replace. Yup, always replace. These are not parts that can be rehabilitated. RIFAs are one of the few things we always bulk replace without any sort of testing. Thanks, Jonathan
[cctalk] Re: 8" floppy diskette storage cases
> From the USPS Domestic Mail Manual, section 170, subsection 4.1(i): > > "Computer-readable media containing prerecorded information and guides or > scripts prepared solely for use with such media." I've asked and our postmaster has said anything that's not blank is OK (we ship a lot of diskettes!). I'm sure interpretation is basically arbitrary when it comes down to stuff like, "how do we classify these disks from the 70s that someone is inexplicably writing new data to in 2022?" Thanks, Jonathan
[cctalk] KIM-1 Boards of the Past
I finally herded together the extant pictures of the KIM-1s I've had in the past and did a writeup: http://www.glitchwrks.com/2022/09/18/kim1-boards-past TL;DR is that during college I found a KIM-1 in an employer's warehouse. Later, I found a box with five more! These were all Virginia Tech surplus, and one of them is likely the first KIM-1 used for classroom instruction there. I'd intended to sell some of them, since who needs six, right? Unfortunately, I was forced to sell all of them, including the one I'd intended to keep for myself, due to economic/financial situations after graduation. I've never seen anyone post about these particular machines, and I haven't seen them exhibited at VCF East, VCF Midwest, or HOPE. None of the sellers contacted me about them after the sale concluded. Is anyone here the owner of one of these particular KIM-1s? Do you know the owner? Did you use KIM-1s while at Virginia Tech? Please let me know! Thanks, Jonathan
[cctalk] Re: Flipping an 8" diskette
> It turns out that some 8" drives can be set to separate the sector holes > from the index hole (separate output pins for index and sector). Doing > so, gives you what amounts to a soft-sectored floppy, regardless of what > the physical object is. The flippy 8" diskette I linked a picture of this morning was written that way. Took me a little time to figure out. Part of a massive lot of diskettes all done like that. I'm guessing the original owner either worked for Varityper at some point, or knew someone who did, and was able to acquire a huge quantity of hard sector diskettes cheaply. > I know that I used a Siemens FDD-200 drive jumpered accordingly to read them. Shugart SA-801 (or 800 with the LSI chip and 801 jumper closed) will also do it! Thanks, Jonathan
[cctalk] Re: Flipping an 8" diskette
> BTW, the greaseweazle can format RX01 format diskettes quite nicely. Any PC that can do single-density can (with ImageDisk or similar), as well as basically all CP/M boxes with 8" drives. That's how I format new RX01 media. RX01 can of course be up-converted to RX02 format with XXDP. Thanks, Jonathan
[cctalk] Re: Flipping an 8" diskette
> Someone suggested punching a notch in them and using both sides. > Was that even possible on 8" disks? Sure, but you have to punch an offset index hole: https://imgur.com/a/6vdR6NE That's a single-sided flippy 8" diskette (it's also hard-sector but that's not really relevant). 8" diskettes have different positions for the index sensor window depending on whether it's single or double sided.In the above pictures, the rightmost hole is the original index window. If it were a factory double-sided diskette (for use in drives with two heads), that index window would be further to the right. Thanks, Jonathan
[cctalk] Re: "Revival" of a dedicated Micropolis webpage on internet
> I think it was Dysan that first showed up with reinforcing ring kits Probably, "Grabettes." > Then why was is it that DD media bought well after HD media was available, in > use, and the norm still had the reinforced ring? Tradition? You might be putting it in an old drive. It was also available without, I had several thousand without reinforcements from Verbatim, bought in bulk bags. Thanks, Jonathan
[cctalk] Re: "Revival" of a dedicated Micropolis webpage on internet
> The last time I checked, bitsavers had information on the 1015, 1016 and > 1115 floppy drives (I have all three models). Did the VG use something > different? No, but I didn't find the model numbering w.r.t. first chassis vs. expansion chassis very clear, especially between the older "blue box" drives and newer "beige box" drives, and the new Micropolis site lays it out plainly with a table of possible model numbers. The new site was one of the higher results for one of the expansion chassis model numbers I'd searched. Thanks, Jonathan
[cctalk] Re: "Revival" of a dedicated Micropolis webpage on internet
I stumbled across that the other day, looking for information on their 100 TPI drives commonly used with Vector Graphic stuff. I was very surprised to find it! Thanks, Jonathan --- Original Message --- On Tuesday, August 16th, 2022 at 03:42, P Gebhardt via cctalk wrote: > > > Hello list, > > by coincidence, I came across this website: > > https://www.micropolis.com/ > > It seems to have been set up by a former employee of Micropolis with > information about Micropolis products done until the late 90s. > > Cheers, > Pierre > > - > http://www.digitalheritage.de
[cctalk] Re: Dec rl02 disk pack shelf design
I have a friend who has one of the wire rack RL style pack racks, which looks a lot like the one pictured. I've thought about having a wireform manufacturer do a run of them. Aforementioned friend is willing to loan it for dimensional capture/reproduction. Is this something people would be interested in? If so I can set up a preorder information-gatherer and get interest numbers. Final form would probably be stainless wire to avoid having to chrome it. I'd try very hard to have it made in the USA, but would consider offshore manufacturing if the price was too high (as is the case with circuit boards, for most of our products/projects). Thanks, Jonathan --- Original Message --- On Tuesday, August 9th, 2022 at 06:26, Joshua Rice via cctalk wrote: > > > > I have definitely seen pictures of them stacked edge-on. Since they were > essentially identical physically to the IBM 5440 disk packs (though > formatting would be wildly different), i imagine that might be a good > place to start in regards to existing designs. Alternatively, it should > be trivial to knock one together with some ply and dowels. > > https://collection.motat.nz/records/images/xlarge/35979/3a9db5d799ac1fe3783402cbe0e8a525fcd10503.jpg > > > Cheers, Josh > > -- Original Message -- > From: "devin davison via cctalk" cctalk@classiccmp.org > > To: "General Discussion: On-Topic and Off-Topic Posts" > cctalk@classiccmp.org > > Cc: "devin davison" lyokob...@gmail.com > > Sent: Monday, 8 Aug, 2022 At 21:21 > Subject: [cctalk] Dec rl02 disk pack shelf design > Hello, > I have many rl02 disk packs for my pdp 11/34 and 11/05. I have just been > stacking them upright, but that has not been the safest or the most > space > efficient. Were any kinds of shelves made for these disk packs, perhaps > similar to 9 track hanging tape racks? Trying to make things look more > organized too. > Hoping someone here has one and can share a pic, perhaps it is a design > i > can duplicate and make with some woodworking tools. > Thanks, > Devin D.
[cctalk] Cheap Lantronix Hardware
All, Per the LAN-attached serial thread, here's another cheap Lantronix device: https://www.ebay.com/itm/123577635191 This is a LRS-2, which is basically a two-port LRS-1, one of their older models of serial bridges. The LRS-2 is nice not only for the two ports, but because it also has AUI and thinnet. No PSU, but it's a typical 12V 1A center positive supply. Thanks, Jonathan
[cctalk] Re: Connecting a physical terminal via LAN to Serial Port
> When I looked at the manual for the Lantronix UDS1100 I did not see any > mention of it being able to be used as Telnet client. PDF Page 54. You put it in manual CONNECT mode, modem emulation, and type "ATDT10.20.30.40:23" on most modern Lantronix devices. I have no personal experience with the UDS1100, but I've got the UDS10 and UDS100 devices kicking around the shop. Thanks, Jonathan
[cctalk] Re: Connecting a physical terminal via LAN to Serial Port
> At least that's how I would configure things Yeah that's basically it. You can often assign aliases so that e.g. `CONNECT RAID` executes a Telnet to a specific IP/DNS name, and many support setting up a default or automatic connection so that as soon as the terminal autobauds it just connects to whatever the default is. All of this will require device-specific commands, but they're all similar and at this point basically support the same feature sets. Devices like the Lantronix UDS series also allow you to add a virtual COM port to your OS, so that you see /dev/ttyXX in *NIX (COMx in Windows) and when you connect to it, you're really going out over Ethernet to the serial device. Thanks, Jonathan
[cctalk] Re: Connecting a physical terminal via LAN to Serial Port
> i.e. there is no device that make a shell or a telnet client available to a > terminal and I will have to roll my own. You may of course choose to DIY but there have been several common and cheaply-available-used solutions presented to you. The default behavior of most terminal servers (single port or otherwise) is, "connect your terminal, hit RETURN a few times, Telnet/rlogin/SSH/whatever to whatever host you desire." Thanks, Jonathan
[cctalk] Re: Connecting a physical terminal via LAN to Serial Port
> I have used the Lantronix UDS1100 for Ethernet/RS232 bridgingmaybe too > pricey new, but available on ePay The older models (LRS-1, LRS-2, UDS10, etc.) also work fine. If you have more than one terminal, look at a small terminal server. There are a few terminal server models that go for serious money (e.g. DECserver 700s, for some reason) but most of them cost more to ship than to buy! Thanks, Jonathan
[cctalk] Re: Odd Unix computer Bio-Rad SRC 3200
Doug, > A few years ago I got it to power on and it runs Unix variant, their > product name was Idris. I have 16 floppies (dated 1992) that came with > the system, but the hard disk has died. Interesting! I have a Multibus system that runs Idris, very little information seems to be around on it. Mine's a straight 68K. > What are the minimum requirements for BSD? With an '030 you should be able to run NetBSD-CURRENT, slowly :P You would of course have to write drivers for any unsupported hardware you need. Thanks, Jonathan
Re: Vintage Computing Hosting [Was: List migration]
We do hosting for a few other hobbyists, and Andy Meyer has his Sony SMC-70 pages on users.glitchwrks.com subdomain: http://users.glitchwrks.com/~ahm/smc70/ Not really advertised as a service, just one of those things where a few friends have needed a place to host a few things! Thanks, Jonathan --- Original Message --- On Monday, July 11th, 2022 at 09:50, Bill Degnan via cctalk wrote: > > > > > > > > The new hosting is provided by the Chicago Classic Computing group. > > > > > > Many thanks to Jay West for hosting the lists for 20 years! > > Who else provides free vintage computer-themed web site hosting as a group > service? I know neurotica.com (LSSM) does too, and I realize a lot of > people have home servers that host their web sites on the subject, still, > right? > > All of my servers are on AWS at this point, although I still have a large > rack at home with dormant / test servers with aging OS's. Red Hat 6 > anyone?... > > I have the space to host a mirror or two, should there be a need. My > company hosts a mirror for > https://fjkraan.home.xs4all.nl/comp/ > on > https://www.vintagecomputer.net/fjkraan/ > > Bill
Re: Memory Card Explorer for the Elan P423
> I ended up getting a PCI bus PC Card adapter based on the TI PCI1131 > PCI-TO-CARDBUS CONTROLLER UNIT chip. I set that up in a Linux system > and eventually managed to get some MTD (Memory Technology Devices) > software installed so that I could read and write to a variety of > linear flash cards. Careful doing this, always flip the write protect switch! Default behavior, when the kernel/pcmcia-utils is trying to figure out what's in the slot is to run down a list of identification steps. The final one is to scribble on the card's memory space to see if it's writable SRAM! Blasted a card just by inserting it a few years ago, fortunately one I already had backups of. If you don't wish to futz with expensive commercial software or rolling your own, you can almost certainly use the Data I/O card utils with a generic ISA to PCMCIA adapter. I have their actual branded hardware, and it's a Vadem PCMCIA chip that follows whatever the early Intel standard was. Software is available on the Data I/O groups.io file archive. The Data I/O software includes basically "dd for Flash cards." Thanks, Jonathan
Re: cleaning up edge connectors
DeOxit works pretty good for cleaning up connectors that still have serviceable surface finishes, but yeah, temporary at best if the surface finish is gone. We use it to clean up all sorts of connectors that are just regular dirty, pots, etc. Thanks, Jonathan --- Original Message --- On Friday, April 29th, 2022 at 16:35, Bill Gunshannon via cctalk wrote: > > > On 4/28/22 18:02, Mike Katz wrote: > > > I use DeOxit Gold to clean my PDP-8 boards edge conectors: > > > I have DeOxit but I saw that as a very short term solution (no > pun intended :-)). I think I will try my idea of using solder > with a little silver in it if I can find some suitable. > > bill
Re: cleaning up edge connectors
> Copper? Mine all look like solder. Probably copper underneath but > the exposed part is lead which probably explains why they seem to > corrode so easily. Ah, yeah, if they're finished in matte tin or HASL, I just reflow leaded solder on. A little bit of Superior #30 flux will make it flow nice and flat. If you don't have liquid flux suitable to it, put solder on and remove excess with solder wick. Thanks, Jonathan
Re: cleaning up edge connectors
If there's bad/deep corrosion, I hit it with the ink eraser (I have a bunch of Eberhard-Faber ones that look like a wooden pencil, you sharpen them like a pencil too). If that won't touch it, I use the stainless steel toothbrush. Corey Cohen has some plating solution that you dip a pen in, intended for jewelry repair. The plating does not hold up well over copper, you need a layer of nickel over the copper first. So, if you're removing down to the copper, you'll have to find a way to put nickel on first. Thanks, Jonathan --- Original Message --- On Thursday, April 28th, 2022 at 15:47, Bill Gunshannon via cctalk wrote: > > > > I am hoping to restore my TRS-80 Model-I(s). As is usually > the case with these the edge connectors are badly corroded > and dirty and cleaning them with an eraser really doesn't > help much. Back in the day there used to be something you > could get that let you "gold plate" the edge connectors. > Is anything like that still available? How about reflowing > the pads using something like silver solder? > If neither of these is doable or practical, what are people > doing to clean up these connectors? > > bill
RE: new Z80 monitor ROM works with no RAM
> Dang! That Z80 computer looks AWESOME. Sure does! Simpson 260 sitting on the bench too :P Thanks, Jonathan
Re: IMSAI SIO2 cable part number
Bill, Let me know right quick if you'll be at VCF East and I'll make you a pair, I have both kinds of IDC ends. I'm heading out first thing tomorrow morning though as I have work in the northeast before VCF East. Thanks, Jonathan --- Original Message --- On Monday, April 18th, 2022 at 15:03, Bill Degnan via cctech wrote: > > > Hi all... > What is the cable partnumber for the IMSAI SIO2? I need to order a > set of cables. I thought in all of my boxes and boxes of cables I > might have one...but nope. > > Here is a picture: > > https://deramp.com/downloads/mfe_archive/010-S100 Computers and > Boards/00-Imsai/10-Imsai S100 Boards/Imsai SIO-2 dual serial IO/SIO with > cables.JPG > > Thanks in advance. > > BIll
Re: Data recovery (was: Re: SETI@home (ca. 2000) servers heading to salvage)
> SSD's are a different beast, if you're going to put data > on them that you do not want recovered I would recommend encrypting the > drive before using it, then when done delete/destroy the key. That > should turn your drive into a useless (but format-able) chunk of silicon. That's our take on it. SSDs get FDE or they don't leave. Secure Erase is nice for blowing away old formatting/partitioning, but we're not trusting it on sensitive customer data. Thanks, Jonathan
Re: PDP 11/24 - A Step Backwards
> What surprises me (a little) is that there is a commercial outfit > willing to work on something so old. It's essentially what we do. I doubt there's a directory of all the small shops that work on legacy equipment, but consider that some of this stuff runs CNC machines that are still in use. Depending on the industry and product, it's *way* cheaper to keep an old machine that's run not-full-time operational than to retool and recertify. Thanks, Jonathan
RE: Testing H745 Regulators
> I always forget that the VAC is the RMS and not the peak-to-peak. I will > look for a minimum rating of 100V. 600V bridge modules are often more cost effective, and more likely to be in stock. That's why I went with the Vishay part I used. If you can't find what you need due to shortages, you can also use a Faston tab rectifier and solder wire legs to it. Thanks, Jonathan
RE: Testing H745 Regulators
I used a Vishay GBPC3506W-E4/51, which is 600V 35A, 400A inrush rated. Looks like they're currently on-order at Mouser, I don't know about other suppliers. The GBPC3506W-E4/51 is a little thinner than the bridge rectifier DEC used originally, which sometimes matters. For the 5411086 board in my PDP-11/10, height does matter, as it shares a heatsink with other parts. I stacked a few washers under the center of the bridge: http://www.glitchwrks.com/images/dec/pdp1110_psu_repair/rectifier_spacer.jpg Thanks, Jonathan --- Original Message --- On Thursday, February 17th, 2022 at 17:57, Rob Jarratt via cctalk wrote: > Hmmm this would suggest 200V 20A > > https://archive.org/stream/bitsavers_decfieldSeeTechnicalManual1972_19126909 > > 8/DEC_Field_Service_Technical_Manual_1972_djvu.txt rather than 35A. Given > > the 20-30VAC input though, I presume a 50V part would be OK still? > > > -Original Message- > > > > From: Rob Jarratt robert.jarr...@ntlworld.com > > > > Sent: 17 February 2022 22:38 > > > > To: 'Brent Hilpert' bhilp...@shaw.ca; r...@jarratt.me.uk; 'General > > > > Discussion: On-Topic and Off-Topic Posts' cctalk@classiccmp.org > > > > Subject: RE: Testing H745 Regulators > > > > Sorry it has been a while responding. I have been looking further at my > > H745 > > > regulators this evening. Below is what I have found and my responses to > > the > > > various questions. > > > > In summary, it looks like the rectifier may be faulty. It is marked > > NSS3514. > > > I believe it is a 35A part. Can anyone suggest a suitable replacement? > > Maybe > > > something like this: > > > > https://uk.farnell.com/taiwan-semiconductor/gbpc35005w-t0/bridge- > > > > rectifier-1 > > > > ph-35a-50v-thd/dp/2677250?st=rectifier which is rated 50V and 35A? > > > > Thanks > > > > Rob > > > > > -Original Message- > > > > > > From: Brent Hilpert bhilp...@shaw.ca > > > > > > Sent: 27 January 2022 03:33 > > > > > > To: r...@jarratt.me.uk; Rob Jarratt robert.jarr...@ntlworld.com; > > > > > > General > > > > > > Discussion: On-Topic and Off-Topic Posts cctalk@classiccmp.org > > > > > > Subject: Re: Testing H745 Regulators > > > > > > On 2022-Jan-26, at 3:41 PM, Rob Jarratt via cctalk wrote: > > > > > > > I am trying to test a couple of H745 regulators with a DC bench PSU > > > > > > > > and I am having some problems with testing them. > > > > > > > > My bench PSU is a twin unit so I can supply the +15V required as > > > > > > > > well as the "AC" input using 20VDC from the other half of the bench > > PSU. > > > > > The problem is that I don't think the bench PSU can supply enough > > > > > > > > startup current to allow the regulator to run. It can only supply 5A > > > > > > > > max. > > > > > > > > I have seen with the H744s that if I put too big a load on them, > > > > > > > > then they can't start because of the heavy startup current required. > > > > > > > > I can start them with a lower load and then add load once the > > > > > > > > regulator is running without breaching the current limit of the PSU. > > > > > > > > With the H745s I have tried reducing the load to see if I can get > > > > > > > > them to start, but a 10R load appears to be too much and the > > > > > > > > regulators draw the full 5A without outputting -15V. > > > > > > > > I have two H745s, both exhibit the same behaviour. I suppose they > > > > > > > > could both have the same fault, but I am inclined to think that > > > > > > > > perhaps they need a higher startup current than I can supply. Can > > > > > > > > anyone > > > > > > > > confirm this? > > > > > > 20V on a 10 ohm load: current = 2A. > > > > > > 15V, 1.5A. > > > > > > In this regulator design there is no path for more current than that > > > > > > which > > > > > > the > > > > > > load draws, aside from temporary peak currents to charge capacitors. > > > > > > If you're drawing 5A DC from the bench supply, something beyond > > > > > > 'failure to start' is wrong. I would expect this supply to operate at > > > > > > small load > > > > > > regardless. > > > > That's interesting. On the H744s I have observed that if I have a high > > load the > > > bench PSU current limiter operates and the regulator cannot output +5V, > > but > > > if I start with a lower load and then add load, it can continue to > > operate. Is > > > the H745 different to the point that I shouldn't expect this kind of > > behaviour? > > > If it is the same, then why do the H744s do this? I have tried waiting a > > few > > > moments to allow the input capacitor to charge up, but the regulator just > > > > does not start. > > > > > What is happening to the bench supply voltage? Does it go into current > > > > > > limit? > > > > > > Does this bench supply have an adjustable current limit?, so that you > > > > > > could > > > > > > run it up starting at a low current while taking measurements. Or, > > > > > > does > > > > > > the > > > > > > current respond with some linearity to varying the input
Re: WTB: DEC VSXXX-AA Mouse or Compatible
Wow, that was quick! Mouse acquired. Thanks, Jonathan --- Original Message --- On Friday, February 11th, 2022 at 10:06, Jonathan Chapman via cctalk wrote: > All, > > I'm looking for a DEC VSXXX-AA "hockey puck" mouse or compatible for a > VAXstation 3100. > > Thanks, > > Jonathan
WTB: DEC VSXXX-AA Mouse or Compatible
All, I'm looking for a DEC VSXXX-AA "hockey puck" mouse or compatible for a VAXstation 3100. Thanks, Jonathan
Re: More switchmode power supply grief - Cisco IGS router
Mean-Well is a maker of drop in power supplies. They sell a wide variety of sizes and output configurations. The supplies are (mostly) not expensive, though not as cheap as something you might dig up on e.g. AliExpress. They also won't burn your house down :) The name is rather unfortunate. All of the big part suppliers carry them. I have had better luck hitting the Mean-Well site and figuring out what I need, then searching the model # on e.g. Mouser. Often, it is cheaper to use two modules rather than finding one do-all with the current ratings you need, but the IGS should have fairly straightforward power requirements. Sounds like we have the same kind of IGS! Thanks, Jonathan --- Original Message --- On Saturday, February 5th, 2022 at 17:17, Peter Coghlan via cctalk wrote: > What's a "Mean-Well module"? I somehow find myself imagining: > > "I put a new module in my router. It blew up. At least it meant well" :-) > > (My IGS has the rather heavy and over-engineered divider shelf with the > > main board underneath and the fan and power supply above.) > > Regards, > > Peter Coghlan > > Jonathan Chapman via cctalk wrote: > > > With that much carnage, I'd probably drop a Mean-Well module in there. I > > > > believe there would be enough room for one or two in the IGS I have > > > > (taller white box, divider "shelf" over the mainboard, I don't know if > > > > there was a lower profile model). > > > > Thanks, > > > > Jonathan > > > > --- Original Message --- > > > > On Saturday, February 5th, 2022 at 09:17, Phil Blundell via cctalk > > cctalk@classiccmp.org wrote: > > > > > On Thu, Feb 03, 2022 at 06:06:10PM +, Peter Coghlan via cctalk wrote: > > > > > > > Today I finally managed to check it out. The ceramic F4A mains input > > > > fuse > > > > > > > > beside the power switch on the back panel had blown. When I opened it > > > > up, > > > > > > > > I found a POWER-ONE MAP80-4000 power supply. The main chopper transistor > > > > > > > > labelled Q1 on the PCB is almost a dead short. It is a large plastic > > > > > > > > packaged FET mounted on a piece of aluminium which is in turn screwed to > > > > > > > > the case for heatsinking. Unfortunately, there are no markings on it so > > > > > > > > I have no idea what to replace it with :-( > > > > > > > > As Q1 is shorted across all three terminals, whatever drives it may be > > > > > > > > damaged too :-( > > > > > > Does that PSU have a PWM controller IC, or is it built entirely from > > > discretes? > > > > > > If there is an IC driving the chopper transistor then you may be able to > > > get > > > > > > some clues about the likely characteristics of the transistor from the IC > > > > > > datasheet. Is it definitely a FET? Some, particularly older, designs used > > > > > > bipolar transistors there. > > > > > > As you say there is a fairly high likelihood that other components on the > > > > > > primary side will have blown up as well so you might be looking at a > > > fairly > > > > > > extensive repair. Are there any other obscure, unmarked devices or is this > > > > > > the only one? > > > > > > p.
Re: More switchmode power supply grief - Cisco IGS router
With that much carnage, I'd probably drop a Mean-Well module in there. I believe there would be enough room for one or two in the IGS I have (taller white box, divider "shelf" over the mainboard, I don't know if there was a lower profile model). Thanks, Jonathan --- Original Message --- On Saturday, February 5th, 2022 at 09:17, Phil Blundell via cctalk wrote: > On Thu, Feb 03, 2022 at 06:06:10PM +, Peter Coghlan via cctalk wrote: > > > Today I finally managed to check it out. The ceramic F4A mains input fuse > > > > beside the power switch on the back panel had blown. When I opened it up, > > > > I found a POWER-ONE MAP80-4000 power supply. The main chopper transistor > > > > labelled Q1 on the PCB is almost a dead short. It is a large plastic > > > > packaged FET mounted on a piece of aluminium which is in turn screwed to > > > > the case for heatsinking. Unfortunately, there are no markings on it so > > > > I have no idea what to replace it with :-( > > > > As Q1 is shorted across all three terminals, whatever drives it may be > > > > damaged too :-( > > Does that PSU have a PWM controller IC, or is it built entirely from > discretes? > > If there is an IC driving the chopper transistor then you may be able to get > > some clues about the likely characteristics of the transistor from the IC > > datasheet. Is it definitely a FET? Some, particularly older, designs used > > bipolar transistors there. > > As you say there is a fairly high likelihood that other components on the > > primary side will have blown up as well so you might be looking at a fairly > > extensive repair. Are there any other obscure, unmarked devices or is this > > the only one? > > p.
RE: Testing H745 Regulators
Get yourself a largeish 24V transformer, I use an old 8A Stancor: http://www.glitchwrks.com/images/dec/pdp1110_psu_repair/5411086_under_test.jpg The AC input can be between 20-30V so it's not critical. Plenty of other "control transformer" type units would do fine. You shouldn't need a lot of current on the 15V rail. Thanks, Jonathan --- Original Message --- On Wednesday, January 26th, 2022 at 19:22, Rob Jarratt via cctalk wrote: > > -Original Message- > > > > From: W2HX w...@w2hx.com > > > > Sent: 27 January 2022 00:11 > > > > To: r...@jarratt.me.uk; Rob Jarratt robert.jarr...@ntlworld.com; General > > > > Discussion: On-Topic and Off-Topic Posts cctalk@classiccmp.org > > > > Subject: RE: Testing H745 Regulators > > > > Any chance you have a second supply you can parallel with the one you're > > > > using? Some bench supplies are dual supplies and have a parallel mode so > > > > you can benefit from both sides of the supply and they can track the same > > > > voltage. Or just put two supplies in parallel with the same voltage set on > > both > > It is already a twin PSU, I am using one half to power the AC input and the > > other half to power the +15V input. > > I do have a separate bench PSU I could use for the +15V and twin up the > > actual twin PSU, so I might try that next. > > > 73 Eugene W2HX > > > > Subscribe to my Youtube Channel: https://www.youtube.com/c/w2hx- > > > > channel/videos > > > > -Original Message- > > > > From: cctalk cctalk-boun...@classiccmp.org On Behalf Of Rob Jarratt via > > > > cctalk > > > > Sent: Wednesday, January 26, 2022 6:42 PM > > > > To: General Discussion: On-Topic and Off-Topic Posts > > > > cctalk@classiccmp.org > > > > Subject: Testing H745 Regulators > > > > I am trying to test a couple of H745 regulators with a DC bench PSU and I > > am > > > having some problems with testing them. > > > > My bench PSU is a twin unit so I can supply the +15V required as well as > > the > > > "AC" input using 20VDC from the other half of the bench PSU. The problem > > is > > > that I don't think the bench PSU can supply enough startup current to > > allow > > > the regulator to run. It can only supply 5A max. > > > > I have seen with the H744s that if I put too big a load on them, then they > > > > can't start because of the heavy startup current required. I can start > > them > > > with a lower load and then add load once the regulator is running without > > > > breaching the current limit of the PSU. > > > > With the H745s I have tried reducing the load to see if I can get them to > > start, > > > but a 10R load appears to be too much and the regulators draw the full 5A > > > > without outputting -15V. > > > > I have two H745s, both exhibit the same behaviour. I suppose they could > > > > both have the same fault, but I am inclined to think that perhaps they > > need a > > > higher startup current than I can supply. Can anyone confirm this? > > > > Thanks > > > > Rob
Re: Typing in lost code
I recently dealt with this with the DaJen SCI monitor listing out of the manual. The copy is pretty bad, and either their printer was having issues, or slashing of "zero" vs "O" was inconsistent somehow. OCRing it produced more of a mess than just sitting with the original and a text editor open side-by-side. I can't imagine it would've worked out well to have someone who wasn't familiar with 8080 assembly language transcribe it, I had a rough enough time on my own, and ended up having to compare the assembly output to a known-good ROM dump to get the last of the discrepancies out. Thanks, Jonathan ‐‐‐ Original Message ‐‐‐ On Sunday, January 23rd, 2022 at 10:11, Paul Koning via cctalk wrote: > I've run into that situation too, with listings so difficult that even a > commercial OCR program (FineReader) couldn't handle it. At the time Tesseract > was far less capable, though I haven't tried it recently to see if that has > changed. > > Anyway, my experience was that the task was hard enough that it needed > someone with knowledge of the material. It may be a contract typist could do > a tolerable job but I have my doubts. Typing, say, an obsolete assembly > language program if you see it merely as a random collection of characters is > going to produce more errors than if the person doing the typing actually > understands what the material means. > > One consideration is the effort required to repair transcription errors. > Those that produce syntax errors aren't such an issue; those that pass the > assembler or compiler but result in bugs (say, a mistyped register number) > are harder to find. > > paul > > > On Jan 22, 2022, at 8:57 PM, Mark Kahrs via cctalk cctalk@classiccmp.org > > wrote: > > > > No, OCR totally fails on olde line printer listing. At least the ones I've > > > > tried (tesseract, online, ...) > > > > On Sat, Jan 22, 2022 at 8:06 PM Ethan O'Toole et...@757.org wrote: > > > > > Can the listings be OCR'ed? > > > > > >- Ethan > > > > > > > > > > Has anyone ever used Amazon Mechanical Turk to employ typists to type in > > > > > > > > old listings of lost code? > > > > > > > > Asking for a friend.
Re: seeking Motorola M68MM01A2 documentation
> He has a lot of Exorciser boards and manuals to scan so I will let him > step forward when he's ready for that. But I do greatly appreciate > getting this manual. Nice! Looking forward to that manual dump when it does happen. I haven't done a ton with EXORbus due to the lack of documentation...it keeps me from buying more stuff I'd otherwise have to reverse engineer. > I think Jos' TEK_BB SBC will be the winning solution and thanks to Jos > for sharing it and Jonathan for running with it. This way many people can > run Altair 680 or SWTPC 6800 code on a small footprint development board. It does look like just the thing for a right-now easy solution! I'll probably still move forward on especially the compatible Glitchbus board set, but not as urgently :P Thanks, Jonathan
Re: seeking Motorola M68MM01A2 documentation
> Excellent information Jonathan! Glad to share! I get the impression that people often think I'm on some ideological soapbox when I tell them not to use $flybynite_pcb but really there are big differences in quality. > I generally carry the s100computers and many RetroBrew board Thank *you* for helping keep cool projects stocked and available! I know I've ordered a few things from you after the N8VEM->RetroBrew change. Thanks, Jonathan
Re: seeking Motorola M68MM01A2 documentation
Mike, We use PCB Cart for boards with hard gold edge contacts, like our DEC prototyping board, Apple II protoboard, XT-IDE, etc. They are the same Chinese board house used by s100computers.com and N8VEM/RetroBrew Computers. Results are pretty good for the price. Expect to order 25 to make hard gold edge plating worthwhile. It'll pretty much double the price of the board, but PCB Cart does proper selective hard gold, not "heavy ENIG" (not a thing) or some other nonsense. A lot of the cheaper places will only plate "hard gold" over ENIG, which I assume means they don't actually have a selective process at all. Make sure to specify an edge chamfer if it's a typical card edge connector, otherwise it'll be routed square and a little difficult to insert/you'll have to dress it down with a file. If practical for the board, remove unused contacts from the edge connector. They charge per-contact as a way to guesstimate their gold costs. Thanks, Jonathan ‐‐‐ Original Message ‐‐‐ On Wednesday, January 19th, 2022 at 12:05, Mike Katz via cctalk wrote: > Johnathan, > > I saw you will be ordering boards pretty soon. > > I need to order some boards for my PDP-8/E but I've never ordered boards > > before. > > What board house do you use? Have you ever specified gold fingers before? > > Any advice would be greatly appreciated. > > Thanks, > > Mike > > +1 (773) 414-1044 > > On 1/19/2022 9:49 AM, Jonathan Chapman via cctalk wrote: > > > Chris, > > > > I'm probably going to order some of these on my next circuit board order > > (this week or next), do you want a set of them? Seems they are of course > > "hacking required," which is fine by me :P > > > > Thanks, > > > > Jonathan > > > > ‐‐‐ Original Message ‐‐‐ > > > > On Wednesday, January 19th, 2022 at 10:24, Chris Elmquist via cctalk > > cctalk@classiccmp.org wrote: > > > > > On Wednesday (01/19/2022 at 03:35PM +0100), Jos Dreesen via cctalk wrote: > > > > > > > On 19.01.22 13:15, Jonathan Chapman via cctalk wrote: > > > > > > > > > That's a neat board! Where can I/we order one? > > > > > > > > > > With me... > > > > > > > > 20 Eur for the set of 2 + shipping. > > > > > > > > If you are in the US it is probably cheaper to order new ones locally. > > > > > > > > Note that I never completed the documentation or wrote the code for the > > > > hex keyboard. > > > > > > > > But it does run the Tektronix board-bucket BASIC via serial port ! > > > > > > > > Find more on ftp://ftp.dreesen.ch/TEK_BB > > > > > > > > ah ha! that's what I was looking for. Will check it out in detail. > > > > > > I think I am "forum challenged" as all I could see at the original link > > > > > > were renderings of the board. > > > > > > Thanks Jos. Maybe this will be the ticket... > > > > > > Chris > > > > > > Chris Elmquist
Re: seeking Motorola M68MM01A2 documentation
Chris, I'm probably going to order some of these on my next circuit board order (this week or next), do you want a set of them? Seems they are of course "hacking required," which is fine by me :P Thanks, Jonathan ‐‐‐ Original Message ‐‐‐ On Wednesday, January 19th, 2022 at 10:24, Chris Elmquist via cctalk wrote: > On Wednesday (01/19/2022 at 03:35PM +0100), Jos Dreesen via cctalk wrote: > > > On 19.01.22 13:15, Jonathan Chapman via cctalk wrote: > > > > > That's a neat board! Where can I/we order one? > > > > With me... > > > > 20 Eur for the set of 2 + shipping. > > > > If you are in the US it is probably cheaper to order new ones locally. > > > > Note that I never completed the documentation or wrote the code for the hex > > keyboard. > > > > But it does run the Tektronix board-bucket BASIC via serial port ! > > > > Find more on ftp://ftp.dreesen.ch/TEK_BB > > ah ha! that's what I was looking for. Will check it out in detail. > > I think I am "forum challenged" as all I could see at the original link > > were renderings of the board. > > Thanks Jos. Maybe this will be the ticket... > > Chris > > -- > > Chris Elmquist
Re: WARNING: Clear QIC Tape Bands
Just as a follow-up, I retensioned and read both tapes with clear bands this morning, and they're fine. Since they were parked, there shouldn't have been anything important there, and it looks like the removed oxide is staying on the band. Thanks, Jonathan ‐‐‐ Original Message ‐‐‐ On Wednesday, January 19th, 2022 at 10:46, Chuck Guzis via cctalk wrote: > On 1/18/22 22:32, Alan Perry via cctalk wrote: > > > On 1/18/22 8:22 AM, Chuck Guzis via cctalk wrote: > > > > > You should be warned that Plastibands > > > > > > do deteriorate after a year or so--I have a package of them that cannot > > > > > > be stretched without breaking. > > > > Do you keep them in sealed bags? I keep mine in a zip-lock and the ones > > > > that I got a couple years ago stretch just fine. (I checked after I saw > > > > this.) > > No, I didn't--I did keep them in a dark, cool place, however. Now, I > > keep bands in my freezer. > > --Chuck
Re: seeking Motorola M68MM01A2 documentation
That's a neat board! Where can I/we order one? Thanks, Jonathan ‐‐‐ Original Message ‐‐‐ On Wednesday, January 19th, 2022 at 04:08, jos via cctalk wrote: > On 19.01.22 01:22, Chris Elmquist via cctalk wrote: > > > On Tuesday (01/18/2022 at 11:35PM +), Jonathan Chapman wrote: > > > > > How's about a Glitchbus board set that's compatible? I was planning on > > > doing it anyway. > > > > > > That would be very cool. Something along those lines was my plan B and > > > > > > I even dug out a tube of 6802's for the effort. I think I could wire > > > > > > up a prototype over a weekend. MC6802 is a nice "cheat" as you don't > > > > > > have to mess with the two-phase clock stuff. > > > > What would be really slick is an SBC that has everything on it to be > > > > either an Altair 680 or an SWTPC 6800 just by changing some jumpers, > > > > switches, etc. and putting the correct ROM monitor on the board. > > Something around these lines ? > > https://forum.vcfed.org/index.php?threads/tektronix-board-bucket-6800.54128/page-5#post-835416 > > Yes, it runs, I still have some PCB's left. > > Works with both 6800 or 6802, memory map is defined with a GAL. > > Jos
Re: seeking Motorola M68MM01A2 documentation
How's about a Glitchbus board set that's compatible? I was planning on doing it anyway. Thanks, Jonathan ‐‐‐ Original Message ‐‐‐ On Tuesday, January 18th, 2022 at 16:45, Chris Elmquist via cctalk wrote: > On Tuesday (01/18/2022 at 03:37PM -0600), Mike Katz wrote: > > > If the software is using ROM routines then the address doesn't matter for > > > > the applications. If not, you can create an abstraction layer (set of > > > > drivers for the ACIA, 6875 Timer and PIA) and if all of the code is written > > > > to the abstraction layer then all you need to do is link in the appropriate > > > > binary for the abstraction layer. This will work for both C and machine > > > > language. > > Understood but I don't want to force the developer to make different code > > for this machine than for the real 680. This is an attempt to get him > > something that he can use to make code for the real 680 without having > > a real 680. > > I have a real 680 myself but I'm not up to shipping it around, loaning > > it out, etc. yet still want to help the effort. But since I am not the > > one actually doing the effort, I wanted to help by providing something > > that was usable without having to change his approach. > > Thanks for the suggestions though. > > Chris > > > On 1/18/2022 2:14 PM, Chris Elmquist wrote: > > > > > On Tuesday (01/18/2022 at 02:01PM -0600), Mike Katz wrote: > > > > > > > I think it might be easier to modify the 680 prom for the I/O addresses > > > > of > > > > > > > > the board rather than modify the board to match the ROM. > > > > > > > > Agreed-- except the goal, which I failed to elaborate on, is to come > > > > > > > > up with an Altair 680 development environment so that someone can port > > > > > > > > some code to the platform without having the real thing. I wanted to > > > > > > > > make that environment as close to real as possible (without having front > > > > > > > > panel switches and LEDs)-- which means having the I/O in the same place > > > > > > > > as the original as well as the authentic PROM code running. > > > > > > > Especially if the address decoding for the I/O is done in PAL (10L8 for > > > > > > > > example). > > > > > > > > No PALs on the board but there is a bipolar PROM (82S129). I'm not > > > > > > > > adverse to making a new one of those or bodging something that drops > > > > > > > > into that socket to modify the decoding if neccessary. I was just hoping > > > > > > > > to not have to butcher the board itself too much. > > > > > > > Some 6800 address decoding was done with 74LS138s. This had the > > > > potential > > > > > > > > to be inefficient in terms of memory usage or if the '138s were cascaded > > > > > > > > then propagation delay could become an issue. > > > > > > > > Yes. This seems to be a limited function CPU board and I suspect it > > > > takes > > > > > > > > that approach just to get the four PROMs and I/O decoded very coarsely. > > > > > > Chris > > Chris Elmquist
Re: WARNING: Clear QIC Tape Bands
> However, "couple (of) months" seems incongruent with "day-to-day". I don't do a reinstall of SunOS every day, though! > I am assuming that the day-to-day operation to mean that the source data > is still accessible on the source system. As such, it's probably simply > a matter of annoyance when a QIC* fails and you must re-do the process > that was using it. Yeah, it's not like irreplaceable data is being lost. But when they fail, you have to at least re-band another tape, and with this stuff pulling oxide off, probably clean the drive too. And of course write a new tape out. > *Can I use /just/ QIC as a proper name or should I say /QIC/ /cartridge/ > analogous to VIN number? "Tape" is I think what most people call them :P Thanks, Jonathan
Re: WARNING: Clear QIC Tape Bands
> I wince at the idea of running with QIC tape. But my experience is with > QIC-80 tapes of the '90s Yes, small ftape QIC-80s were certainly in the "not great" category! Thanks, Jonathan
Re: WARNING: Clear QIC Tape Bands
> My opinion is that if you're trying to use DC carts for archival storage, you should have your (tape) head examined. Not archival storage, just day-to-day operation on old stuff, like Sun3/Sun4, AT UNIX PC, etc. > As someone that has worked with computer tapes for nearly 40 years, I have to > question the sanity of this. These > tapes are HOW old? What was their intended lifespan? While we all > like to keep our hardware as original as possible, does it really make > sense to try to run systems in this day and age with QIC tapes? Works well enough for my needs :) I've got a small stack of QICs I use primarily with the Suns, they are reliable enough. Again, we're not storing launch codes on these or shooting them to the moon or something, I just want tape bands that don't destroy tape. Thanks, Jonathan
WARNING: Clear QIC Tape Bands
https://i.imgur.com/48EfOQG.jpg That's after sitting parked a couple months. I have a Dysan doing it too. The Dysan had been re-banded with a boiled 3M band and run for years like that with no shedding. I have another Dysan with a green Plastiband in it which is also fine, minimal/no shed. So, I think we may need to re-evaluate if the clear Amazon cheap "plastibands" are perhaps totally incompatible with tape. I know, I know..."just use the band to get data off." But I want to *run* QICs without having to destroy them constantly. Thanks, Jonathan
RE: Mate-n-lok connector for H744 Regulator
> Note that both have a minimum order :-<. As for pins: If folks don't want to deal with minimums, we can make up cables with the correct connector, we stock the housings, crimps, and have the correct TE crimp tool for them. That said, connectorpeople.com are good to deal with, we use them for weird connectors. Their checkout process is...not Web 2.0 :) Thanks, Jonathan
Re: Source for replacement caps in H744 regulators
> The terminal posts are aluminum, and can develop an oxide > layer that prevents good contact. > > Removing and replacing them might improve the contact. I have experienced this personally with TO-3 regulators, too. I had a bunch of triple voltage Power One linear supplies that would intermittently brownout, had to chase the threads in the TO-3 sockets (which served as a case terminal connection) and put toothed washers under the screws to bond the TO-3 aluminum case. Thanks, Jonathan
RE: Source for replacement caps in H744 regulators
> One of the H744 regulators whines FWIW, none of mine are silent under load. If they're not being loaded (e.g. on a test bench, with no dummy load, or if you have all the boards out) they can whine excessively due to no minimum load. > it seems higher than the expected values printed on the meter Beware cheap test equipment. $client has a few of these Chinese handheld LC/RLC meters, they're wildly inaccurate on some parameters, including ESR on large electrolytics. We've got a proper Gen-Rad RLC Digibridge in the shop to compare against. We couldn't figure out why some of their tuned filter stages were failing QC at a much higher rate than expected. They were off-frequency because the cheap meters were giving consistently incorrect measurements when trying to match capacitors. That said, it's not like replacing them with new will *hurt* -- it just might not fix the whine. Thanks, Jonathan
Re: cctalk Digest, Vol 88, Issue 2
> Why couldn't 120V be derived from either of the 240V phase and the > grounded corner via a 2:1 transformer? It can. That's often how, say, an Edison base decorative luminary is run when all other lighting is 277V (the ratios would of course be different). Otherwise someone invariably screws a 120V bulb into a socket providing 277V. > I would wonder if it would be > possible to ground the center tap on the secondary side of the 2:1 > transformer mentioned above or not. Sure, that's one way of getting split phase 120/240V on a delta system. You've basically made high leg delta the hard way. You do also get to use a completely separate two busbar panel for your 120/240V loads, which prevents the "oops that empty breaker spots give 208V to ground" mistake. A more common method of supplying significant small loads on a delta service is to use a delta:wye transformer and provide 120/208Y. This provides more even loading on the three-phase service, and also provides 120/208Y for, say, computers :P The center/star connection in the secondary is grounded at the transformer. Thanks, Jonathan
Re: cctalk Digest, Vol 88, Issue 2
> For what it's worth, the building I bought has two services installed when > it was built in 1921 - single phase 120/240 for lighting loads, and 240V > Delta for three phase loads. I bet you have a fun electrical system :D > It's the even more obscure corner-grounded delta I love the reaction when a tech or plant electrician encounters corner-grounded delta for the first time. The meter says one phase is missing, yet everything is fine! Often coming off a backfed transformer turning 208Y into 480 delta, which also apparently blows some minds. I did once see what happens when a new guy connects the neutral on the Y primary side. Thanks, Jonathan
Re: 3-phase power; was: cctalk Digest, Vol 88, Issue 2
> The IIRC oldest US generating station still in operation (on original > hardware anyway) is at Mechanicville, NY. Well that ruined my evening, Wikipedia says the generating station now uses the power to mine bitcoins, because it's more profitable than selling it to the public grid. Thanks, Jonathan
Re: 3-phase power; was: cctalk Digest, Vol 88, Issue 2
> much of it related to Niagara Falls and other power systems > modeled after it. The IIRC oldest US generating station still in operation (on original hardware anyway) is at Mechanicville, NY. It is hydroelectric and originally fed 40 Hz AC to Schenectady. They just sped up the alternators when they connect it to the 60 Hz grid! I hear the European equivalent of US 25 Hz traction power is 16.6 Hz. Thanks, Jonathan
Re: cctalk Digest, Vol 88, Issue 2
> High-leg delta is independent of open- or closed-delta. That's correct. > Open delta uses two single-phase transformers primaries connected to > phases AB and BC. A to C is also valid, presumably it's rotated if there's a lot of open delta in an area (again, why?) to balance phases. > On high-leg, one of the secondaries is center-tapped and split > single-phase is fed from the center tap and either end of the secondary. Right, and you get a mostly unusable "high leg" w.r.t. neutral, usually 208V though I don't know what it ends up actually being in open delta with poor/uneven loading. The 120/240 power available is also supposed to be derated, IIRC it's only supposed to be 5-10% of total service load. High-leg delta exists so you can have 120/240 lighting and appliance loads in a building that consumes mostly 3-phase, like a machine shop with an office. In most areas you aren't allowed to have more than one type of service to a building (not sure if that's true for double-fed sites, never seen one with two kinds though). I've heard the Power Company usually doesn't want to install high-leg delta anymore for a variety of reasons: the load limit, people not understanding they need to skip a breaker, 120/208Y having become the usual form of smaller service three phase, etc. > Said configuration can be a 3-winding full delta configuration or the > open-delta as detailed above. Right, there's one or two of those services in town here for a couple of small commercial buildings. Four wire high leg open delta off the pole, two transformers on the pole. Thanks, Jonathan
Re: cctalk Digest, Vol 88, Issue 2
One of the top Google results: https://www.engineeringradio.us/blog/2012/02/the-open-delta-three-phase-service/ Really really, there's only two pigs on the pole. And yet, delta power, though at a lower rating than transformer nameplate (vs. if you had three). Thanks, Jonathan ‐‐‐ Original Message ‐‐‐ On Tuesday, January 4th, 2022 at 14:56, Grant Taylor via cctalk wrote: > On 1/4/22 8:52 AM, Jonathan Chapman via cctalk wrote: > > > Indeed. This is not corner-grounded delta. Once you figure out open > > > > delta, look at dog-leg. > > I did some brief reading on open delta and now think that it requires > > three lines, independent of ground. So I fail to see how open delta > > would be any benefit save for a simpler transformer (fewer coils) or > > fewer transformers. It seems as if you would have the same line and > > insulator cost as more common (closed) delta. > > > > > Grant. . . . > > unix || die
Re: cctalk Digest, Vol 88, Issue 2
> I apparently need to do more reading. Indeed. This is not corner-grounded delta. Once you figure out open delta, look at dog-leg. Thanks, Jonathan
Re: cctalk Digest, Vol 88, Issue 2
> I have seen some roads where the utility has 2 of the phases plus > neutral going down them, not true 2-phase power, but 2 phases 120/240 > degrees apart with the third phase just not present. Yes, that's open delta. There are one or two small commercial buildings here in town that still have open high leg delta service -- that's 240V delta, and one of the 240V transformers is center-tapped to give 120/240 split phase for small loads. My guess is, aside from saving on wire, insulators, etc. (not significant in town), the real savings is on disconnects and the extra transformer. Thanks, Jonathan
