I've come across linear PSUs [1] which have a reasistor in parallel with the pass transistor. Under the correct load conditions, this resistor would not pass enough current to give the required output votlages, but along wit hthe pass transistor it will The problem is that with too little load (or no load at all), the pass trnasistor can be fully cut fof and the output votlage will stil lrise too hig hdue to this reissotr. One to watch for! [1] The HP59500 HPIB interface fr the Multiprogrammer is one such... Thge HV power supplies in mpst monitorsm, certainyl those usign a true flyback transofrmer, _are_ swithcing supplies, techncially. It is also not at all uncommon to have the rgulated, particualrly in colour mnoitors, where changes in the EHT will affect convergence and purity [2]. But given that a totally black screen is essentiually no beam current and thus no load on the supply it is common for such suppleis not to min no load. [2] Sometime I will tell you about the PD500 'shunt stabiliser triode' and the Bang and Olufsen TV with 2 output stages and thus 5 valves in the EHT cage so as to avoid the PD500 and its attendant Xrays. -tony

I can think of 2 : Magnetic focussing. If you put a longtitudinal magnetic field on the CRT, the electrons that leave the gun not on the axis will follow helical paths (apporcimately) with the axis touching each turn of the helix (_NOT_ with the helix centred on the axis as at elast one physics book I had to suffer said!). If you adjust the magneitc field, you can end up with the electrons ending up on the axis at the screen, thus prodcuign a sharp spot. Trace rotation. For mcu hthe same rason, if you have a logititudial magneitc field after the nrmal lelectorstatic delfleciton plates, you cna rotate the trace on the screen. This is sometimes done in good 'scopes to get the trace to exactly line up with the graticule lines (particualrlly if those are on the CRT faceplate, so the CRT can't be rotated wrt them. Now, an electormagetically-focussed, electortatically deflected CRT is very uncommon. I don't think I've ever seen one. In fact by the 1960s, magnetic focussing was rare anyway, it was easier to put an extra electorde in the electron gun than arrange the focus coil or mpermanent magnets. But... As otehrs haveaid, the number owires going to theis yoke is a good clue. A deflection yoke will ahve 2 coils (obviously). THis implies 4 wires. Magnetic defleciton is good if you want a linear-ish scan at a constant frequency. You cna use the self-inductance of the coil as part of an LR time constant. It's less good if you want anything else. You need a driver stage which cna overcoem the back-emf of the coil. For 'random' vector motion, this can incolve quite high voltages if you want a reasonable scan rate. Alas I am not (as yet) psychic. I can only base my comments on the facts I am given :-). And said comemtns are much the same as others have said. With the unit in fornt of me I may well notice things that are signfiicant (as woudl other people here), but until I see them I don't know they're significant... An accelerating anodebetween thre defleciton plates and screen (in an electrostaitcally deflected CRT) is not unheard-of, it is gnerally called PDA (no, not what you are thinking -- Post Deflection Aceleration). But it's normally only used in 'scope CRTs, If it's a vector display, there can't really eb a flyback transformer, in that there is no scan anf flyback. There will be an HV power supply, and this may well use soemthign that looks liek a normal flyback transformer -- in fact it may be a taansformer that is used a a flyback transforme rin a raster monitor -- but it will have its own drive circuitry. My worry is mcuh the same as yours. With onyl the HV vconnected, if the HV supply is operational, the whole CRT, inclduign any outer coatings, will get up to this votlages. They wil lthen flash over to anythign they can This is unlikely to b dangerous for you, but it may well zap transistors all fof the machine. -tony

On Aug 4, 2014, at 2:12 PM, Rick Bensene <rickb at bensene.com> wrote: Sure sounds like magnetic deflection. Electrostatic is traditional for this, but magnetic deflection for a stroke display has certainly been done. As I mentioned, CDC had one of each in their mainframe consoles: electrostatic in the first generation, magnetic in the second. And those displays had a harder job, because the characters were plotted in an unpredictable order as opposed to an order fixed in the circuit design as I would assume for your calculator. paul

Yes, I was totally remiss in publically thanking Al and CHM for making the Wyle Labs calculator materials that are on BitSavers available. This documentation will prove invaluable in the event that I need to troubleshoot the logic of the machine. For those interested in early electronic calculator architecture, the reading in the Maintenance & Service manual is really interesting. -Rick Bensene The Old Calculator Museum http://oldcalculatormuseum.com this

I wrote: the To which Tony D. responded: represet a digit machine, just The Friden 130/132 did the same kind of thing. The machine had no ALU to speak of. Just a set of four counters that would be connected together (and counting up or down) in differing ways depending on the operation being performed. Everything was done by counting up sums digit at a time, by counting pulses coming out of the delay line. The Friden 130/132 logic was significantly more elegant (and much less complex electronically) than the Wyle Scientific, despite the fact that the Scientific had larger numeric capacity, and three memory registers versus the single storage register of the Friden 130/132. The 130/132, though, benefited dramatically from the fact that it was a stack-oriented machine, which made it a lot less complicated to use (once you got used to it). Keeping track of the register usage on the Wyle Scientific can be a bit of a chore. -Rick

On 08/06/2014 10:52 AM, Rick Bensene wrote: Not 7 or 9, but 8 in a miniature tube? I don't think I've ever seen one like that. The nice thing about glass tubes is that you can often guess at least the function by examining the visible parts of the internals. You can count the number of electrodes, determine if there's a heater-cathode setup or just a filament. Sometimes you can even figure the pinout. --Chuck

Hello, all, Here's another update on the Wyle Scientific WS-02 calculator. Yesterday I tested out the power supplies with the logic chassis and CRT connections and deflection board disconnected, and dummy loads made from automotive brake light lamps in parallel on the +12 and -12V supplies. These provided enough load on the supplies to check for ripple under load, and assure that regulation was also working properly under load. The power supply passed with flying colors, still <5mV ripple on all of the supplies, and the regulation was within a tens of millivolts of specified voltage. I also tested the supply by varying the mains voltage by +/- 10%, and regulation stayed stable. I also loaded the -30V supply with a single bulb, not knowing what kind of current it was capable of sourcing, and it also was stable and had minimal ripple. I also did a check of the high voltage supply, using a rubber-insulated screwdriver with a heavy piece of stranded copper wire wrapped around the shank tightly, connected to a NE-2 lamp, the other side of which was connected to chassis ground. I was able to get a solid discharge through the lamp from the supply by moving the end of the screwdriver close to the point where the high-tension wire connected into the HV power supply. So, it appears that the power supply is working. Thankfully, I didn't get zapped. Another discovery is that the tubes in the power supply are not triodes, and I also miscounted the pins. These are 9 (not 8) pin mini tubes, and I was able to get a part number off of the second tube by examining it very closely with a bright light while it was still plugged into its socket. The tubes are 1V2 diodes. I'm not sure what they are for, but on closer inspection of the circuit board that they plug into, there are a number of transistors that I suspect are wired as an oscillator, but what the diode tubes do is a mystery. The datasheet for the 1V2 tubes says they are primarily used in the flyback circuitry of television sets, so perhaps they are used in a similar way in the HV power supply in the calculator. After running the power supply under load for a few hours, and seeing the voltages and ripple remain very stable, I was confident that I could put the logic chassis back in, and reconnect everything, and try powering it up. I discharged the high voltage section to make sure I wouldn't zap anything when I was installing the logic chassis. I put everything back together, carefully checking everything to make sure it was connected correctly. The designers were thoughtful in that they put keys on all but one of the connectors (the one without the key is the one that plugs into the deflection board, but it was very obvious how it plugs in). I hooked up the DVM's to each of the power supply lines, and slowly ramped up the Variac. After about 70% of mains, the supplies had stabilized at their proper voltages. I could also see the heater in the CRT starting to glow. At around 85%, the display started showing signs of life, but it was very unfocused. As I slowly ramped up to 100%, the display sharpened, and I was greeted by six lines with decimal points that I could move around by changing the decimal point selector. Also, the line that displays the ENTRY register had an intensified 0 at the left end of the display, and there was an intensified 0 positioned at the left-most digit of the ENTRY register. Per the manual, I pressed CLEAR ACCUMULATOR, CLEAR MQ, and CLEAR ENTRY, and the display flickers all zeroes when these keys are pressed, then returned to the "two zeros" display, which is the expected behavior. I then pressed a digit key. The intensified zero moved one digit position to the right, but no digit was entered. Repeated digit entry would move the cursor one digit position to the right for each digit press, but no digit would enter. The BACK SPACE and FORWARD SPACE keys would move the cursor digit as expected. The TO and FROM register keys would move the register selection "0" around as expected. Math operations, which couldn't do much since the only thing in the registers is zero, caused the display to flicker, and then return to the normal display. Pressing square root causes the display to show all zeroes, with an intensified 0 in the MQ register moving from left to right, then returning to the 'idle' display. Pressing the DIVIDE key resulted in the display going to all zeroes, and the machine locking up. I'm assuming that this is because it is trying to divide by zero. So, clearly there is something up with digit entry. Either that, or the delay line is not properly serving as a memory for all of the registers. There is going to have to be some deeper diagnostics done to try to figure out what is wrong. The difficulty is that the logic chassis in the Wyle Scientific was designed to only be replaced as an entire module. The 8 circuit boards are all hard-wired together with countless individual wire jumpers that interconnect the boards, so getting to any of the boards except the front-most and rear-most boards is going to be a challenge. Despite the issue, I'm very pleased it is as alive as it is after all of these years. Thanks again to all for the input on the HV power supply, and the interest in this old calculator. -Rick Bensene

I thought '1' was defind as >0 to <2V filament voltage. 0 was reserved strictly for cold cathode vavles/tubes. IOn any case, I find the US valve numberign system very irritating. It tells you almsot nothign abotu the valve. The heater voltage number has incosistnecies (like the use of 7 and 14 to mean 6.3V and 12.6V on a loctal base -- msot fo the time). The last digit is supposed to be something like the number of useful elemenets. But then a 6C4 is a simple triode, so is a 6J5. I was told you count the metal shell in the last case for some odd reason. I've foudn that if I know what hte vlave is, I can find a justification of the number of useful elements, but trying to deduce waht is is fro mthe code is impossible. No, I prefer the Philips (European) code. There are a few mis-assigned numbers in my experience (for some odd reason a few valves with a '70-series' base code were actually Loctals, not subminiatures), but most of the time it's consistent. A lot of the complaints I've heard come from people who don't realise the meaning of soem bits of the code was changed when they went to 3 digts (from 2 digits). For example, with 2 digts on the end, 'G' at the strt means a 5V heater. So a GZ34 is a full-wave vacuum rectifier with a 5V heater on an octal base. But with 3 digits, 'G' at th satrt means 'miscellaneous heater voltage' So a GY501 is, indeed, a half wave rectifier on a B9G (Magnoval) base with, in fact, a 3.15V heater (IIRC). -tony

There are many, although I cna't find any with the US-style numbers. Apart from the HR1 (another HV rectivier, on a B7G base), there are US subminiatures like the CK505 (pentode), CK509 (tirode), CK510 (tetorde), CK512 (pentode), M54 (tetrode), M64 (tetorde), M74 (pentode) and UK subminiatures like the DF66 (pentode), XFW10, XFW20 (both pentodes), DF70 (anotehr pentode), etc. Sure. The tabels I have say that '7' means 6.3V heater o na loctal base, etc. It's just another exception to the rule that the first digit(s) give the heater/filament voltage. IT's not strictly an American number, I think, but it's the right format : 2D21. That's what I know as an EN91, a xenon-filled tetrode thyratron. B7G base and 6.3V heater (of course) Also watch for UK Mazda (ntohign to do wit hthe car company) valves. These have a similar format number 9digits, letters, digits) but the code is totally different. The first digits do give the heater voltage -- except that 10,20,30 mean for use in series strings of 100,200,300mA. The lettes do give some info about the electrode stucture -- C = frequency changer, D = diode, F = pentode, L = triode, P = output penotode, etc. Yes, but the numbering scheme seems to have been designed nto to give useful information I always liked the term 'kinkless trtrode' for these :-). Over here there waa famous series of GEC output valves, much loved by Audio fanatics called KTxx (KT66 and KT88 being the most common). OF course 'KT' == 'Kinkless Tetrode' The name comes from the fact that hte beam forming plates etc supress the econdary emision from the anode, so the IA-VA curve doe not have the negative resistanve part that is forund in the curve of a plain tetrode. Yes, but there often _is_ a reason for the opcodes, if you search for it. For example, in the hP98x0 procesosr, the memory refernce instructions have the opcode in bits 11...14 of the instruction word. A simialr set of register-reffernce isntrcutions has the opcode in bits 7...4 and the opcodoes are essentially the same. It makes sense. In the microcode, the instruction word (in the Q register) is shfited to get the opcode bits in the same location, so the same microcode fork cna be used to decode the instruction. Of coruse there is no rrason why opcode 000x is load, 001x is compae, etc. You could reassign those with trivial changes to the mocrdoe. Bu that's like sayign there is no logical reason why 'C' in the Philips valve code means triode, 'N' means thyratron, 'L' means output tetrode/pentode, etc. That si arbitrary. But almost all valves coded that way use the same meaning got hte letters. So if you can rememebr the 20-or-so letters adn teir menaings you can figure out what any such valve is. So that, for exmaple, if soembody tells you their radio has a UABC80 in it, you can deduce from the fact athat the 'U' means 100mAheater, it's likely to be a series-string AC/DC set and from the fact taht it's a trible diode (AB) and triode in the same envelope that it's likely to be an AM/FM set (AM detecotr, FM discriminator, and first audio amplfiier). -tony

The Raytheon CK (and QK and RK) series do not fall under the RMA registration scheme. 0Y4? I do not think there was an 0Y3. There was an 0Z3, which was an interesting commercial bomb, but somewhat important. These are not part of the RMA system - or at least the RMA receiving tube system. They are from a short lived RMA system for special purpose and transmitting types, from 1940. Short lived...or long lived - it is still around today, with all those pesky 1Nxxxx diodes and 2Nxxxx transistors. See my previous post. Complaining about the flawed US tube numbering system is like shouting at a barrel of fish. -- Will

On 08/12/2014 03:19 PM, Tony Duell wrote: A web search brings up the 0Y3 germanium diode, so n0body's perfect... Try running a 6L6 as a grounded-grid RF amplifier. Easy to do with the EL34, since the suppressor grid is brought out separately. But I'm sure that you're aware of many applications where that separate grid comes in handy, such as suppressor grid modulation. Anecdote... Back when, the 12.6V heater version of the 807, the 1625, used to be super-cheap as military surplus. You could get a carton of them NOS for about $0.25 each. Some enterprising souls sought to built a GG amplifier using them--the trick was to drill a hole in the base and fish out and separate the beam-forming electrode from the cathode leads, then attach them to one of the unused pins on the 7-pin base. A friend built a GG final for his 160 meter rig using 10 of them in parallel with the heaters in series, powered right from the line. Interesting experiment. --Chuck

On 08/13/2014 02:24 PM, Tony Duell wrote: I think that the venerable 6888 pentode was designed specifically for Grid 3 computer logic applications. Then there were the tetrodes that were classified as "dual control grid". All sorts of interesting stuff to be found in tube manuals. Did the 6BN6 gated-beam tube ever see computer application? I remember seeing some circuits using paralleled triodes in a cathode-follower configuration being touted as transformerless speaker drivers. I don't know if they ever made any headway in the commercial world as such. --Chuck

On 08/13/2014 06:54 PM, Brent Hilpert wrote: Sure, the pentagrid converters, improved version over the old autodyne mixer. There was also the 7A8, 6-grid octode and well as the 6K8, triode-hexode sharing the control grid. Lotsa variety. --Chuck

9 electordes (so 7 grids)? That's nromalyl claled the nonode in the UK. The one I rememebr is the EQ80 -tony

I had to think for a few seconed (I could easily remember hendeka -- 11 -- for soem reason), and I acutally learnt Greek <mumble> yeas a go. 'Must a gentleman know Latin and Greek?' 'No, but he should have forgotten them' :-) -tony

I think the 6888 was developed for the SAGE processors, and perhaps only used there. Every 6888 I have seen - and that is a *lot* of them - has had an IBM/SAGE part number. Probably not. 6BN6s were not computer rated. The much later 6KS6 may have worked, as most tubes from the later years were OK for computer use, even if not specifically rated for it. I doubt so, back in times past, because audio output transformers were relatively cheap, and the big low-mu monster triodes were not. Now things have changed, and 6AS7 and friends often can be purchased for peanuts, so there are indeed tube amplifiers that lack output transformers. One must be very careful with them, and use proper speakers, or there will be trouble. -- Will

Yes, the distortion problem is also an issue, but I think the expense is a bigger one. All newly made quality audio output transformers are very expensive these days, and ones made for the low impedance tubes are really, really, really expensive. Most transformer shops will not even do them, as they are very difficult to make properly. Weight? Meh. Most audiophiles do not care much about weight. Looks are far more important. -- Will

On 08/14/2014 02:57 PM, David Riley wrote: I don't understand audiophile technology anymore--they left me in the dirt when they started selling gold-plated wall (AC line) sockets. I recently ran across an audiophile outfit who stated that they use only carbon composition resistors on the basis that they gave a "warmer" sound than those nasty film ones. I'd have called the sound "noisy" but then, as I said, I'm way out of the loop. --Chuck

On 2014-Aug-14, at 5:06 PM, David Riley wrote: Hmm.. I know a source of many NOS carbon comp resistors from the early 1930s (dogbones, etc). A new retirement fund? No, they'd just come up with some tortured faux-technical explanation for why it doesn't matter on the recording side but does on the playback side. "There's only one instance of the signal on the recording side but once it's been split up and distributed into millions of instances for playback it needs better cables".

On 08/14/2014 05:06 PM, David Riley wrote: I recently was offered to taste a cup of gourmet coffee. I sniffed it and immediately, the odor of burning comp resistor pinged on my olfactory radar. I suspect that much of the gourmet coffee business shares a lot with gourmet audio. --Chuck

On 08/14/2014 07:28 PM, Al Kossow wrote: And I thought it was me. Honest, if I were to set a cup of that stuff on my workbench and turn away momentarily, you'd have me nervously scurrying around looking for the piece of equipment that was self-destructing. Some odors you never forget, like burning selenium rectifier. Like rotten eggs, but with a metallic-garlic overtone. --Chuck

Oops, and I forgot to mention the all-important fact that most reviewers are utterly FOS and simply love to hear themselves rattle off industry lingo - and no matter what anyone might try and argue, we ALL have our listening preferences, and they are much more influential than many are willing to admit, particularly on the pages of some rag like TAS or Stereophile. On Thu, Aug 14, 2014 at 10:10 PM, drlegendre . <drlegendre at gmail.com> wrote:

On Aug 15, 2014, at 12:20 AM, Chuck Guzis <cclist at sydex.com> wrote: Litz wire has its place where it makes a measurable difference. That place is typically in high-frequency (e.g. SMPS) transformers, where skin effect actually makes a difference; at audio frequencies, it's really a fraction of a dB. It depends... are you using NOS gold-plated cans from Campbell's '87 Chicken With Stars line with the packing string? You really must, or you won't be getting the proper dimensionality and soundstage - Dave

On Thu, Aug 14, 2014 at 11:12 PM, Chuck Guzis <cclist at sydex.com> wrote: In that size, oxygen-free copper still contains far too much oxygen. However, for a (relatively) small fee I'd be happy to treat their 3/4x12" copper bus bar that using my proprietary process that mitgates the audible effects of the oxygen. It also alters the bond angle between the copper atoms in the lattice, similar to John Ellis water. That makes it sound absolutely amazing!

Incidentally, I refer to the sort of people being described here as 'audiophools' :-) An audio shop once tried ot sell my father some 'monocrystaline copper speaker cable'. His reply 'I assume it comes shaped to fit my room, and is annealed aftwer bending.' 'What?' 'Well, if I bend the cable I will disrupt the crystal lattice, it will no longer be strictly monocrystaline' 'What?' 'I am a physcial chemist. Cut the B*llsh*t.' I rememebr the time he was lookign at high-end CD players. One such, very expensive, used the cheapesyt Philips CD mechansim (the same one in mu external CD-ROM drive, actually...) and the decoder board broke _every_ design rule inthe Philips datasheets for the ICs uses. When I found decoupling capacitors several cm for the IC they were supposed to be decoupling (when the data sheet said they had ot be SMD parts under the IC) I knew the design was, shall we say, inferior. Perhaps some audiophool could tell me why domestic audio equipment never has balanced inputs and outputs. Now that, by eliminating problems from ground noise, could make a real differnece. But that's engineering, not snake oil, I guess. -tony

I've worked iwth (and inside) measuring instruments accurate to at least 6 figures. They never use exotic cables :. When the likes of Tek, HP/Agilent/whoevber_they_are_now, LeCroy, etc start using these odd techniques that are claimed ot improve sound in audio systems I will start to take notice... -tony

On 08/16/2014 03:15 PM, Tony Duell wrote: Ah, but you miss the point--the exotic audio fans like to use terms such as "warm", "brilliant" and I don't remember what else. These are terms that essentially describe things that can't be measured with your silly equipment. Come to think of it, it does remind me of wine... --Chuck

On 08/16/2014 06:48 PM, Fred Cisin wrote: ...or a box--I'm not proud. --Chuck

On Aug 15, 2014, at 5:15 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote: Some does. I have a set of Nakamichi microphones that have balanced outputs, I forgot the name of the connector but it?s widely used in professional audio. Fortunately it comes with adapters for my unbalanced home-grade recorder. paul

On 08/15/2014 06:05 PM, Paul Koning wrote: XLR is what I think you're after. When you have low-output mics that have to traverse 100 feet to the amplifier, induced hum can be a real problem. I like the beefiness of XLR--I've used them for power supply (low voltage DC) connectors. They come in 3, 4, 5 and 6 pin versions. --Chuck

I am not sure I'd class microphones as domestic audio equipment any more. But anyway.... Things like moving-coil microphones, moving coil speakers, pickup cartridges, etc are essentally symmetircal and floatingwrt grounds. So they can all befed into differntial inputs with no ground noise pronlems, etc. Electret microphones, with bilt-in preamplifiers (Maybe jsut an FET) can be floating, (they are oftne powered by an internal battery) but the asymmetry of the circuit meansthat the stray capacitance from each side of the output to ground is not the same. This probbly has no effect at audio frequencies, though. I was thinkign more of mains-powered devices like radio tuners, CD players/DACs, tape recorders, etc. Not one domenstic unit that Iv'e ever seen has differential audio inputs/outpus. XLR? Siad adpater may just easrth oen side of the output form the microphone and feed the other side inot the unbalanced input :-( -tony

On Thu, Aug 14, 2014 at 10:38:01PM -0600, Eric Smith wrote: [...] The problem is, ultra-crappy and ultra-long cables are standard, as they come with consumer-grade kit. Anybody who gives even the slightest damn about audio quality should replace them. However, you don't need anything fancy: if you're paying more than ten quid, they saw you coming. I tend to repurpose the crappy cables for S/PDIF and composite video, neither of which need such a wide SNR, just so long as there's not too much attenuation at a few MHz.

On Aug 15, 2014, at 11:11 AM, ben <bfranchuk at jetnet.ab.ca> wrote: They do, but not in the major consumer stores. I?ve seen very civilized cable prices even for harder stuff like HDMI and fiber, via mail order. But the 5 cent RCA connector does just fine for that. Better conenctor in the 1950s? Not clear. ?UHF? is mechanically slightly better than RCA but electrically not really. And by the way, Heathkit used RCA connectors in their transmitters, so they apparently judged it to be acceptable for 30 MHz, 100 W. It?s surprising how simplistic a connector you can get away with so long as you?re below microwave. F connectors aren?t much, either, but they are small enough that they don?t cause trouble. (Anything that?s no bigger than a few percent of wavelength is just about invisible electrically.) paul

On Fri, Aug 15, 2014 at 5:47 AM, Peter Corlett <abuse at cabal.org.uk> wrote: I've never gotten cables longer than 2m with any consumer electronics, and that's not "ultra-long" in my opinion. I was considering roughly 10m or longer as "ultra-long". I've also never gotten poor-quality cables with any of my AV gear, but then, I only have purchased fairly reputable brands (e.g., Denon, Epson, Kenwood, Marantz, Onkyo, Panasonic, Philips, Pioneer, Sony, Tascam/Teac). I don't doubt that crappy (or no-name) brands might provide crappy cables, if they bothered to provide any at all.

On Thu, 14 Aug 2014, William Donzelli wrote: I did some searching through the Whirlwind archives at MIT, and believe you're correct about the 6888. MIT worked with Sylvania to develop the SR-1782A (6888), an improvement over the 7AK7 which was developed for the Whirlwind system. The 6888 was used as a gate tube throughout the AN/FSQ-7. Mike Loewen mloewen at cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/

On Fri, 15 Aug 2014, William Donzelli wrote: It looks like the Z-2177 was an improved 5965, designed by IBM and produced by GE at the Owensboro, KY plant: http://dome.mit.edu/bitstream/handle/1721.3/39427/MC665_r06_M-2374.pdf http://dome.mit.edu/bitstream/handle/1721.3/40353/MC665_r13_M-3002.pdf http://dome.mit.edu/bitstream/handle/1721.3/39796/MC665_r10_M-2955.pdf http://dome.mit.edu/bitstream/handle/1721.3/39794/MC665_r10_M-2981.pdf http://dome.mit.edu/bitstream/handle/1721.3/39778/MC665_r10_M-2815.pdf http://dome.mit.edu/bitstream/handle/1721.3/39787/MC665_r10_M-2635.pdf http://dome.mit.edu/bitstream/handle/1721.3/39810/MC665_r10_M-2722.pdf http://dome.mit.edu/bitstream/handle/1721.3/46022/MC665_r14_6M-4386.pdf It appears that GE was working on a redesigned Z-2177-3 (0528), but was eventually told to stop the project: http://dome.mit.edu/bitstream/handle/1721.3/45987/MC665_r14_6M-3674.pdf A search for 0158 yielded no results. Mike Loewen mloewen at cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/

Am 13.08.2014 um 00:19 schrieb Tony Duell: This is the naming scheme of Pro Electron. See http://en.wikipedia.org/wiki/Pro_Electron -- Holger

On 08/11/2014 08:52 PM, William Donzelli wrote: http://www.hupse.eu/radio/tubes/6M6.htm Where the Europeans decided to jump in on the US numbering scheme. Even with G and GT versions. The little "x" was meant as a wildcard. And it was very localized. I have no idea what I'dve done if I ran across a receiver using, a say, UA55, though it may not have seemed too unusual to a guy from the UK. --Chuck

Yes, that is why I said it is an unregistered type. There were quite a lot of those, and are almost always of European origin. The RMA had no control over those. Unregistered types with a US number, originating -- Will

That makes it sound like an electormagnetic deflected CRT. This is entirely possible,, electormagnetic vector dispalys are, perhaps less commmon than electroictica ones, but certianly not unheard-of Technciallly, for there to be a flyback transfoormer, there has to be a flyback (basically, when the beam is quickly returend form the right hand edge to the left hand edge of the screen -- the 'flyback' -- there is energy stoed i nthe yoke and output transformer htat has to go somewhere. Not surpisingly got get a firly large back EMF which you might as well step up and use to provide the HV for the CRT, etc (thanks Blumlein). With a vector display there is no repetifvie motion of the beam, so no true flyback. No guarantee there will be enough energy stored i nthe yoike//transforemr to use for the HV. So basically vector displays have to have an HV supply that is independant of the deflection. Are there any pins comign otu the side of the CRT neck (other than the HF connecotr on the flare)? If so, those are pretty mcuh going to be the delfeciton plates (amongst other things) so it'll be electrostatic. Incidnetlaly, how many conenctiosn are there to the base of the CRT? Remember if it's electrostatic, there will have to be 4 for the deflection plats [1] Two for the heater in all CRTs. So if you only ahve 6 or 7 connecitons , it's not going to be electrostatic, there aren't enough pins for the electrodes. Yes. Sure. -tony

On Aug 4, 2014, at 8:57 PM, Rick Bensene <rickb at bensene.com> wrote: Cathode is another. Then you have at least two electrodes to accelerate and focus the electron beam. So depending on the structure of the electron gun system, you?d see 5 or 6 pins in use. paul

It's been done, but it';s very uncommon. I even heard about a direclty-heated colour CRT (3 guns), It was a right pain, you had to have 3 indpeendant heate supplies whcih were flating nad low capctiance to ground. You see, the video mopdualtion was applied to the heaters. In any case, the sahape of a filimanet is not ideal for an electron source in a CRT Waht is moderately more common is to have the cathod intenrally connected to the heate. This solves the 'shape' problem. It doesn't solve the fact that the CRT heater supply has to bouce around with the video signal, bit in devices that don't modulate the brightness msuh (like 'scopes, ratehr than monitors) thsi is not so much of a problem. It saves a base pin which can be useful. IT also reduces the versatility of the CRT, which may be a problem... I've jsut worked on an istrument (nothing to do with classic computers) which has a small (3" or so diagonal) slectorstaically-deflected CRT in it. It has 9 pins, no HV connctor aor side pins on the CRT. Jsut 9 connections. Of coruse 4 are for the deflection plates. The got everythign else onto 5 pins by (a) not having a control grid and (b) linking cathode ot heater intenrally. That means the 5 connections were : heater/cathode ; heter ; first acclerator anode ; focus anode; fianl accelerator anode. Odd... -tony

On 08/05/2014 02:06 PM, Paul Koning wrote: Very handy for a modulation checker. I've got a couple of circuit diagrams using one kicking around on my bookshelf. Remember when an oscilloscope was called a "cathode ray oscillograph"? --Chuck

That sounds like a Station Monitor... g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.diy-cockpits.org/coll - Go Collimated or Go Home. Some people collect things for a hobby. Geeks collect hobbies. ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://scarlet.deltasoft.com - Get it _today_!

MY guess is that onyl one of each of the X and Y plates was brought out to a pin, the other 2 were internally connected to one of the anodes. It works, but the linearity suffers a bit. OK for monitoring on a 1" CRT, not for meaking measurements on a 6" CRT... I once worked with a similar CRT, but ona Loctal (B8B) base. Tubualr enveleope, it looked like an EBL21 with a white phosphor in place of the getter. -tony

Tony Duell wrote: ^^^^^^^^^^^^^^^^^^^^^^^^^^ Tony, I usually understand what you're trying to get across, but with this one I'm totally stumped. Peace... Sridhar

'Floating and low capacitance to ground;. The point being that in this colour CRT , the 3 video drive signals were applied to the heaters (moving them wrt ground, not changing the voltage across the heaters, of course). Theis meant having 3 separate heater supplies (so the 3 colours could be individually controlled) and having them low capacitance to ground (so that there was a high impedance to ground at the frequency of the video signal, otherwise fine detail would be lost. A right pain to use.... -tony