Re: The near-mythical IBM color MDA
Correction--it wasn't Glitch who got the pen, it was Trixter. I have trouble with pseudonyms. --Chuck
Re: The near-mythical IBM color MDA
On 08/23/2018 08:31 PM, Eric Schlaepfer via cctalk wrote: > I'm not that lucky! But yes, an early card with the light pen connector > should work. > > The card I used for the demo is a somewhat later revision. I added rework > wires to match the schematic in the technical reference manual of the > earlier revision. I had the original MDA and a rather ancient light pen from some graphics console or another. I hooked it up to a 6-pin Berg header and got it to work, sort of. I didn't use the interrupt 10h BIOS functions, though, but rather accessed the 6845 registers directly. The operation was pretty terrible. The medium-long persistence of the monochrome monitor led to large positioning errors. I recently sent the pen to Glitch, who hasn't gotten back to me to report wether it still works. It was pretty nice with a pressure-activated tip swich with fiber optics coupled to a phototransistor, with a couple of transistors to boost the signal. Black with a coiled cord--6 conductors, I think. --Chuck
Re: The near-mythical IBM color MDA
OK, so the demo was with a "MODIFIED" card. :-) (admittedly a trivial one that brought it in line with published schematic) Which Int10h modes does it support? QBASIC is presumably simpy using the INt10h modes. The MDA by default was in Mode 7. If it will do mode 3, then it can do Lotus in color, etc. Obviously, it doesn't have the RAM to do any "high resolution" modes, . . . On Thu, 23 Aug 2018, Eric Schlaepfer wrote: I'm not that lucky! But yes, an early card with the light pen connector should work. The card I used for the demo is a somewhat later revision. I added rework wires to match the schematic in the technical reference manual of the earlier revision. With either an early MDA card or a modded card, if you fire up DOS 5.0 and have QBASIC, you'll find that the COLOR statement... just works! It's quite strange. On Thu, Aug 23, 2018 at 8:24 PM Fred Cisin via cctalk wrote: On Thu, 23 Aug 2018, Ali via cctalk wrote: Which revision MDA is this? I have an original NEC Multisync and I have a tone of MDA cards including one in one the first 5000 IBM 5150s produced. I would love to get color out of it just for the sake of doing it. Do you still have your demo programs? Do any of yours have the 6 pin Berg connector near the top of the mounting plate? Some did. On CGA, that connector is for light pen. Supposedly some early MDAs had pins 3,4,5 connected (not connected in later ones). That MIGHT be the same ones as have the light-pen? connector. https://www.seasip.info/VintagePC/mda.html#cmda http://www.minuszerodegrees.net/5150/early/5150_early.htm
Re: The near-mythical IBM color MDA
I'm not that lucky! But yes, an early card with the light pen connector should work. The card I used for the demo is a somewhat later revision. I added rework wires to match the schematic in the technical reference manual of the earlier revision. With either an early MDA card or a modded card, if you fire up DOS 5.0 and have QBASIC, you'll find that the COLOR statement... just works! It's quite strange. On Thu, Aug 23, 2018 at 8:24 PM Fred Cisin via cctalk wrote: > On Thu, 23 Aug 2018, Ali via cctalk wrote: > > Which revision MDA is this? I have an original NEC Multisync and I have > > a tone of MDA cards including one in one the first 5000 IBM 5150s > > produced. I would love to get color out of it just for the sake of doing > > it. Do you still have your demo programs? > > Do any of yours have the 6 pin Berg connector near the top of the mounting > plate? Some did. On CGA, that connector is for light pen. > Supposedly some early MDAs had pins 3,4,5 connected (not connected in > later ones). That MIGHT be the same ones as have the light-pen? > connector. > > https://www.seasip.info/VintagePC/mda.html#cmda > > http://www.minuszerodegrees.net/5150/early/5150_early.htm >
RE: The near-mythical IBM color MDA
On Thu, 23 Aug 2018, Ali via cctalk wrote: Which revision MDA is this? I have an original NEC Multisync and I have a tone of MDA cards including one in one the first 5000 IBM 5150s produced. I would love to get color out of it just for the sake of doing it. Do you still have your demo programs? Do any of yours have the 6 pin Berg connector near the top of the mounting plate? Some did. On CGA, that connector is for light pen. Supposedly some early MDAs had pins 3,4,5 connected (not connected in later ones). That MIGHT be the same ones as have the light-pen? connector. https://www.seasip.info/VintagePC/mda.html#cmda http://www.minuszerodegrees.net/5150/early/5150_early.htm
RE: The near-mythical IBM color MDA
> > The NEC Multisync monitor thread reminded me that I used one to produce > a > video, and I thought a few of you might enjoy it. > https://www.youtube.com/watch?v=-TiHFWH4NWk Eric Which revision MDA is this? I have an original NEC Multisync and I have a tone of MDA cards including one in one the first 5000 IBM 5150s produced. I would love to get color out of it just for the sake of doing it. Do you still have your demo programs? -Ali p.s. What other secrets did the original MDA card have?
Re: The near-mythical IBM color MDA
Nice! 2018-08-23 23:29 GMT-03:00 Eric Schlaepfer via cctalk : > The NEC Multisync monitor thread reminded me that I used one to produce a > video, and I thought a few of you might enjoy it. > https://www.youtube.com/watch?v=-TiHFWH4NWk >
The near-mythical IBM color MDA
The NEC Multisync monitor thread reminded me that I used one to produce a video, and I thought a few of you might enjoy it. https://www.youtube.com/watch?v=-TiHFWH4NWk
Re: NEC Multisync monitor manual
The model number is JC-1401 if that helps. On Thu, Aug 23, 2018 at 6:08 PM Charles Dickman via cctalk < cctalk@classiccmp.org> wrote: > I am looking for a manual for the original NEC Multisync monitor. > > Google fails me because of all the follow on monitors had Multisync in the > name. > > -chuck >
NEC Multisync monitor manual
I am looking for a manual for the original NEC Multisync monitor. Google fails me because of all the follow on monitors had Multisync in the name. -chuck
Re: DTC (Was: DTC TakeTen media?
On 08/23/2018 04:12 PM, Fred Cisin via cctalk wrote: > I had a bunch of their DTC-300 HytypeI daisy wheel printers (KSR > terminals) on a pedestal (little card cage in the top back of the > pedestal was main obstacle to conversion to table-top; I can't remember > whether it was a 4004 or an 8008 that they used) I worked for a few years with ex-Qume employees, who had gone to Qume from Diablo Systems. Things were somewhat more incestuous back then. --Chuck
Re: DTC TakeTen media?
An interesting take on the removable media of the time, circa 188: https://ia601603.us.archive.org/30/items/PC-Mag-1988-09-13/PC-Mag-1988-09-13.pdf Starts on PDF page 213. I don't think that DTC ever made a hard drive, but they did package external drives under the TeamMate product line. --Chuck
DTC (Was: DTC TakeTen media?
On Thu, 23 Aug 2018, Chuck Guzis via cctalk wrote: DTC did a lot of strange things. I first knew them as manufacturing a sheet feeder for the Diablo Hitype printer. I still have a few of their disk controller cards and some SCSI controller engineering documents. I had a bunch of their DTC-300 HytypeI daisy wheel printers (KSR terminals) on a pedestal (little card cage in the top back of the pedestal was main obstacle to conversion to table-top; I can't remember whether it was a 4004 or an 8008 that they used) Bringing back 4 of them from a computer swap with a Honda Civic was interesting.
Re: Datic 2000 / Ampex 844 Documentation ?
On Thu, Aug 23, 2018 at 2:37 PM, jos via cctalk wrote: > First time I have seen a 14" drive on a CP/M system > There were some versions of CP/M on the Intel MDS development system (the _original_ CP/M machine) with support for the Intel MDS 740 hard disk system, which was an Intel SBC 206 controller with a CDC 9427H Hawk 14-inch fixed/removable drive, with IBM 5440 style media. I'm not sure whether the CP/M support was provided by Digital Research, or required a third-party BIOS. Starting in 1979, IMSAI sold the CDC Hawk, with support in IMDOS II (a licensed and modified CP/M 1.33). Ohio Scientific offered hard disk systems fairly early on, using 14-inch drives. They supported them in the OS-65U operating system, I suspect that they had CP/M support for them on their systems that included a Z80 processor. The first time I personally used a hard disk with CP/M was in 1981. It was earliest model Corvus disk system that used an IMI 7710 8-inch drive (smoked-plastic enclosure), connected to an Apple II, the latter containing a Microsoft Z80 Softcard. At one point I had to do a low-level format of the drive. You had to get the formatter program from Corvus, and add a jumper to the drive backplane to enable formatting.
Re: DTC TakeTen media?
On 08/23/2018 01:22 PM, jim stephens wrote: > > The Drivetec media was 6mb then 12mb. The 6mb media worked well if you > repunched the floppies as AT high density media, and when DTC died a > huge amount was sold with instructions on how to do that, as the cost of > media was then still high for 1.2mb media. > I've only seen the 3.3MB and 6.6MB versions. The 3.3 was used on the Kypro "Robie". My 6.6 media was sent to me by the tech support fellow at Verbatim, just before they closed their Santa Clara operation. I already had the drive. The Drivetec drives were also sold by DTC as their "TeamMate" series of external drive/controller combos. There's a German auction of the TakeTen here: https://tinyurl.com/yax6tjvc You can see that the drive slot is considerably thicker than a normal floppy disk--and it's identified as a "Removable Cartridge Disk Drive". Again, I don't recall ever seeing the cartridges. DTC did a lot of strange things. I first knew them as manufacturing a sheet feeder for the Diablo Hitype printer. I still have a few of their disk controller cards and some SCSI controller engineering documents. --Chuck
Re: DTC TakeTen media?
On Thu, Aug 23, 2018 at 2:20 PM, Chuck Guzis via cctalk < cctalk@classiccmp.org> wrote: > The thing that really brought Drivetec down was that you had to use > their factory-preformatted embedded-servo floppy media. It was > expensive (about $15 each in 1986). > Same with Iomega ZIP disks (introduced 1994, initially $20 medium), but those were wildly successful. I don't think requiring factory-formatted media was really the problem. It seems more likely that the Drivetec disk only having the capacity of seven floppy disks was the problem.
Re: Datic 2000 / Ampex 844 Documentation ?
another one https://forum.classic-computing.org/forum/index.php?thread/13826-datic/ On 8/23/18 1:37 PM, jos via cctalk wrote: > > Ran into an early CP/M system today, from german company Datic. > It is a single-user 8080 system, featuring a delay-line based CRT output and > an Ampex 844 fixed platter / removable 14" > cartridge driver. > > Is this simply a Diablo 44 equivalent, as I suspect, or is this a true > standalone development from Ampex ? > > First time I have seen a 14" drive on a CP/M system > > Jos
Re: Datic 2000 / Ampex 844 Documentation ?
on the other hand it looks a lot like the Western Dynex drive http://www.glb-online.com/produit5.html http://jim-st.blogspot.com/search/label/dynex http://bitsavers.org/pdf/westernDynex On 8/23/18 1:37 PM, jos via cctalk wrote: > > Ran into an early CP/M system today, from german company Datic. > It is a single-user 8080 system, featuring a delay-line based CRT output and > an Ampex 844 fixed platter / removable 14" > cartridge driver. > > Is this simply a Diablo 44 equivalent, as I suspect, or is this a true > standalone development from Ampex ? > > First time I have seen a 14" drive on a CP/M system > > Jos
Re: Datic 2000 / Ampex 844 Documentation ?
On 8/23/18 1:37 PM, jos via cctalk wrote: > Is this simply a Diablo 44 equivalent, as I suspect, or is this a true > standalone development from Ampex ? they made their own http://www.glb-online.com/disk-never-used1.html I'm mostly familiar with their 80mb SMD drives
Datic 2000 / Ampex 844 Documentation ?
Ran into an early CP/M system today, from german company Datic. It is a single-user 8080 system, featuring a delay-line based CRT output and an Ampex 844 fixed platter / removable 14" cartridge driver. Is this simply a Diablo 44 equivalent, as I suspect, or is this a true standalone development from Ampex ? First time I have seen a 14" drive on a CP/M system Jos
Re: DTC TakeTen media?
On 08/23/2018 12:33 PM, Tom Gardner wrote: > According to DTC's 1987 prospectus the Company began limited shipments of its > TakeTen 10-megabyte removable-cartridge disk drive in December 1986. The > TakeTen is based on technology developed by Data Technology in collaboration > with Eastman Kodak. The storage cartridge is manufactured by Verbatim > Corporation (“Verbatim”), an Eastman Kodak subsidiary, and incorporates a > high-performance flexible magnetic disk encased in a rigid plastic shell. > > The Kodak drive was based on a license from DriveTec > > DTC was acquired Qume and changed its name to Qume. > > It stopped producing these sorts of drives in 1991 I got that information from a Google search also, but the thing doesn't take Drivetec media (I have two Drivetec drives--one with Kodak branding). The TakeTen is also SCSI, where the Drivetecs are more-or-less conventional floppy interface. I also seem to recall that the basic Take Ten IP got passed around a bit--was it Quantum that tried to market it? I don't recall. I don't recall seeing any media "in the flesh" for the thing, ever. Kind of odd for something that was in production for 5 years. By 1991, a removable cartridge drive that held only 10MB was ridiculous. The thing that really brought Drivetec down was that you had to use their factory-preformatted embedded-servo floppy media. It was expensive (about $15 each in 1986). I recall a couple of guys flogging the drives, media and controllers at one of the "Computer Faires" after they'd fallen on hard times. I suspect the same situations prevailed with the ill-fated Caleb UHD drive--you had to buy the preformatted media, which could (accidentally or otherwise) be over-written as a normal 3.5" floppy. (I've got a bunch of those as well--ATA interface). --Chuck
Re: Using M122 keyboards on a PC
On 8/23/18 11:36 AM, Ali via cctalk wrote: > This is incorrect. The Soarer convertor is made for IBM KBs so it may have > issues with Wyse KBs. he sells another model for 4 pin Wyse
Re: Scans of VT05, RK05 and PC04 IPB, TC11 Formatter doc and DC013 chip doc
On 8/23/18 5:56 AM, Mattis Lind wrote: > Finally I found a copy from a book that is about the DC013 chip - not the > best copy unfortunately. But I haven't found > anything like this online. it's in dec/internal/Semiconductor_Handbook_V1_1987.pdf which I put up about a month ago
Re: First 3.5 inch FDD [WAS: RE: Prototype IBM DemiDiskette drive]
On Thu, Aug 23, 2018 at 12:43 PM, Tom Gardner via cctalk < cctalk@classiccmp.org> wrote: > Well it all depends upon what u mean by "first" > > The Sony drive and cartridge were not compatible in many ways with what > became the physical, magnetic and electrical interface standards for the > 3.5-inch drive and cartridge. The standards came out of the "Microfloppy > Industry Committee" (Google it with quotes) organized by Shugart Corp. > Either Shugart or Tandon was the first to ship drives compatible to the > standard. Tandon probably did the first such cartridge. > > The original Sony drive and cartridge died out and Sony didn't come out > with > a compatible set until well after Shugart and Tandon. The early adopters > of > the Sony design like HP then changed to the industry standard design. > AFAICT, the only difference was that the pre-standard Sony 3.5-inch diskettes had a manually operated shutter. The manual shutter and automatic shutter 3.5-inch diskettes are interchangeable with some care. For a while, diskettes were sold that had the automatic shutter, but also had a way the user could latch the shutter open, so that they could be used in early drives that didn't have the pin to open the automatic shutter. I only ever saw the manual-shutter drives in Sony and HP equipment, though I wouldn't be surprised if there were some other uses.
RE: DTC TakeTen media?
According to DTC's 1987 prospectus the Company began limited shipments of its TakeTen 10-megabyte removable-cartridge disk drive in December 1986. The TakeTen is based on technology developed by Data Technology in collaboration with Eastman Kodak. The storage cartridge is manufactured by Verbatim Corporation (“Verbatim”), an Eastman Kodak subsidiary, and incorporates a high-performance flexible magnetic disk encased in a rigid plastic shell. The Kodak drive was based on a license from DriveTec DTC was acquired Qume and changed its name to Qume. It stopped producing these sorts of drives in 1991 Tom -Original Message- From: Chuck Guzis [mailto:ccl...@sydex.com] Sent: Wednesday, August 22, 2018 11:48 AM To: CCtalk Subject: DTC TakeTen media? On the subject of oddball PC media, does anyone out there have media for the DTC "Take Ten" cartridge drive? I've got the drive here, still in original shrink-wrap and packaging, but no media, so I don't have the faintest idea if it still works. As the 5.25" cartridges only held 10MB, I suspect this was a flash-in-the-pan venture. I'd never heard of one back in the day when everyone was using Bernoulli drives. --Chuck
Re: Prototype IBM DemiDiskette drive
On Thu, Aug 23, 2018 at 12:51 PM, Tom Gardner wrote: > It was the SA200 a 2/3rds height (51 mm) 5¼-inch FDD at $118 in quantities > of 5,000 or more. It was sold in 1982 but got killed by the true ½ > heights which Shugart OEMed from Matsushita. > Hi Tom, The SA200 came later, and just from the photographs I can tell that it was a much better-engineered drive than the one I'm referring to. http://www.computerhistory.org/collections/catalog/102677924 http://engineeringhistory.tumblr.com/post/92146695534/shugarts-sa200-525-minifloppy-disk-drive The drives I saw in 1980 were prototypes or engineering samples, and didn't look at all like the SA200.
Re: First 3.5 inch FDD [WAS: RE: Prototype IBM DemiDiskette drive]
On 08/23/2018 11:43 AM, Tom Gardner via cctalk wrote: > Well it all depends upon what u mean by "first" > > The Sony drive and cartridge were not compatible in many ways with what > became the physical, magnetic and electrical interface standards for the > 3.5-inch drive and cartridge. The standards came out of the "Microfloppy > Industry Committee" (Google it with quotes) organized by Shugart Corp. > Either Shugart or Tandon was the first to ship drives compatible to the > standard. Tandon probably did the first such cartridge. I must confess some bewilderment. Around 1981, I did some contract work for an outfit called Preis for their portable computer. I don't recall the nature of the work anymore, but I still have a copy of their BIOS for CP/M. At any rate, the thing used the Sony 0A-D30 single-sided 600 RPM floppies, which held about half as much as the corresponding 8" media (in FM, about 160KB). The major differences were that the Sony drive could access only 70 cylinders, while the 8" drives could do 77. In addition, the Sony spun at 600 RPM, which allowed for the use of an 8" drive interface, albeit at a reduced track capacity over the 8" drive. One other notable aspect was that the Sony's 26-pin interface had no motor control line--the disk spun continuously, just like its 8" relatives. Similarly, it had a head-load solenoid, just like the 8" drives. Media-wise, I believe there was little difference between the Sony floppies and more modern DS2D commodity media. I believe the disk shutters were not sprung, but were manual. I used to have a couple of these drives, but scrapped them because the modern slow 3.5" drives did a better job of handling floppies. Where Shugart fits into all of this, I have no idea. --Chuck
RE: Prototype IBM DemiDiskette drive
It was the SA200 a 2/3rds height (51 mm) 5¼-inch FDD at $118 in quantities of 5,000 or more. It was sold in 1982 but got killed by the true ½ heights which Shugart OEMed from Matsushita. Tom -Original Message- From: Eric Smith [mailto:space...@gmail.com] Sent: Wednesday, August 22, 2018 1:32 PM To: Al Kossow; General Discussion: On-Topic and Off-Topic Posts Subject: Re: Prototype IBM DemiDiskette drive On Wed, Aug 22, 2018 at 1:09 PM, Al Kossow via cctalk wrote: > I just picked up a Model 350 on eBay, just because I'd never seen a > Shugart sub 5" drive. > Unfortunately I don't recall the model number, but there was a Shugart 5 1/4" drive that made it at least to prototype and field test around late 1980 or early 1981. It was supposed to be really inexpensive, but almost plug-compatible with standard drives like the SA400. Unlike the SA390, it did have electronics. Instead of being built on an aluminum casting, it only had bent metal. The head stepping mechanism worked like an 8-track tape. It used a solenoid to advance one track inward; the only way to go outward was the next step from the innermost track returned to the outermost (track 0). The single track step time was incredibly slow; I think it was around 750ms, vs 40ms for an SA400. My employer at the time, Apparat, then famous for NewDOS-80 for the TRS-80, had one for evaluation, but decided not to resell them. It would have required special software support, which Apparat could have put in NewDOS-80. Presumably patches could have been offered for other TRS-80 operating systems. I wasn't told what the retail price of the drive would have been, but I don't think it would have sold well even at 1/4 the price of an SA400.
First 3.5 inch FDD [WAS: RE: Prototype IBM DemiDiskette drive]
Well it all depends upon what u mean by "first" The Sony drive and cartridge were not compatible in many ways with what became the physical, magnetic and electrical interface standards for the 3.5-inch drive and cartridge. The standards came out of the "Microfloppy Industry Committee" (Google it with quotes) organized by Shugart Corp. Either Shugart or Tandon was the first to ship drives compatible to the standard. Tandon probably did the first such cartridge. The original Sony drive and cartridge died out and Sony didn't come out with a compatible set until well after Shugart and Tandon. The early adopters of the Sony design like HP then changed to the industry standard design. Tom -Original Message- From: Fred Cisin [mailto:ci...@xenosoft.com] Sent: Wednesday, August 22, 2018 1:25 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: RE: Prototype IBM DemiDiskette drive >> I just picked up a Model 350 on eBay, just because I'd never seen a >> Shugart sub 5" drive. >> https://www.ebay.com/itm/Vintage-Sankyo-Shugart-Venture-Model-350- >> Computer-Disk-Drive-/253708808435 On Wed, 22 Aug 2018, Ali via cctalk wrote: > Interesting. I wonder if IBM was looking at those drives for use. The seller (or more accurately the seller's father) used to work for IBM Industrial services in Boca Raton. Well, the SA300 (single sided version) were not the first 3.5" drives, but they may have been the first 300 RPM ones with an SA400 interface. (The Sony 600RPM drives would require more changes) The SA300 could be dropped into a 5150 (with only issues of mounting brackets (Erector set) and power connector) and were supported by some OEM versions of MS-DOS 2.11. IBM public support of 3.5" began with PC-DOS 3.20.
RE: Using M122 keyboards on a PC
> terminal keyboards on a PC. But please be aware that ONLY the keys > found on > a normal PC keyboard will work! You can do some remapping, but F13-F24 > will > not be available, and some keys will not operate the same as they did > on the > original keyboard. I have used these to test Wyse (with removable This is incorrect. The Soarer convertor is made for IBM KBs so it may have issues with Wyse KBs. However, on IBM 122 key KBs it works beautifully. You can remap ALL the keys including F13-F24. I have as my main KB an IBM F122 KB w/ the LED lights. I have F13-F24 remapped to windows, menu, and media keys w/ new key caps from Unicomp. -Ali
Using M122 keyboards on a PC
Orihalcon sells nifty Soarers converter cables that let you use most terminal keyboards on a PC. But please be aware that ONLY the keys found on a normal PC keyboard will work! You can do some remapping, but F13-F24 will not be available, and some keys will not operate the same as they did on the original keyboard. I have used these to test Wyse (with removable cables), IBM, and a bunch of AT and XT keyboards. They do not work for ADDS keyboards. Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 830-370-3239 cell sa...@elecplus.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Scans of VT05, RK05 and PC04 IPB, TC11 Formatter doc and DC013 chip doc
I scanned some more documents: The version of the TC11 formatter manual online is not matching the binary that is available. This one is a later version which is a better match. http://storage.datormuseum.se/u/96935524/Datormusuem/DEC/DEC-11-YPTC-D_TC11_DECTAPE_FORMATTER.pdf I found three IPBs. I couldn't find them directly on bisavers: http://storage.datormuseum.se/u/96935524/Datormusuem/DEC/DEC-PC04-IPB-1.pdf http://storage.datormuseum.se/u/96935524/Datormusuem/DEC/DEC-VT05-IPB-1.pdf http://storage.datormuseum.se/u/96935524/Datormusuem/DEC/DEC-RK05-IPB-1.pdf Finally I found a copy from a book that is about the DC013 chip - not the best copy unfortunately. But I haven't found anything like this online. http://storage.datormuseum.se/u/96935524/Datormusuem/DEC/DC013.pdf /Mattis
Re: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
tor 2018-07-26 klockan 12:15 -0700 skrev Chuck Guzis via cctalk: > On 07/26/2018 11:51 AM, Ed Sharpe wrote: > > > > smecc has stashed a huge mother gen set115 60cy in 115 > > 400 cy out. was used to runrca avq 10 raradr > > we have > > but could run many many things... it is huge,,, these things > > exist out there if you need one,... > > 400Hz power was also used in aviation gear. I remember having a > stock > of small surplus 400Hz transformers salvaged from various bits of > equipment purchased on Chicago's "Surplus Row". > > Transformers are much smaller than their 50/60 Hz cousins. > > On the other hand, when I worked in a steel mill, much of the power > distribution was 25Hz. Transformers were much larger. At some > point, > one of the mills converted their lighting from incandescent to > mercury-vapor running from that 25Hz supply. I'm surprised that > nobody > experienced seizures from the flicker. > The electric arc furnace works much better at 25 Hz. The hydro power station in Trollhättan was first built as a 25 Hz because : desiredness of electric power for the metallurgical industry in Trollhätan. Trouble: the other intended customer Gothenburg city wanted 50 Hz. The last 25 Hz generator in Trollhättan was taken off the electric grid in 1959.
