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Re: There is no good time to be SICK
Dennis,
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I am glad to hear that you are ok. I, for one, am in no hurry for you to send the book. I¡¯d prefer that you deal with the higher priority items on your list first. DaveD On Nov 27, 2020, at 15:51, Dennis Tillman W7pF <dennis@...> wrote: |
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Re: worst condition Tektronix scope?
Yes, I did. Also to Vintage Tek. I believe he reviewed many of the 7854
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comments as he was troubleshooting the scopes I gave him. I encouraged him to put up the replacement 454 rear feet for sale or maybe post the 3D print files to the group. Steve H. On Fri, Nov 27, 2020 at 4:17 PM Jim Ford <james.ford@...> wrote:
I hope you pointed him to TekScopes and TekWiki.Jim Ford Sent from my |
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Re: worst condition Tektronix scope?
I've looked in the catalogs for both HP and Tektronix.? I haven't seen any mention of a Tektronix Pope.
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Harvey (nor HP) Would one be used to look at the output of an old style Vatican Camera? H. On 11/27/2020 4:42 PM, Jeff Dutky wrote:
Richard Steedman wrote:Have you read the full description of this guy's scope?The color of the smoke is VERY important: it tells you whether or not we have a new Pope. |
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Re: 528A TV waveform monitor.
Various things still have NTSC type outputs.
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1) older video equipment, VCRs, TV cameras, some surveillance TV cameras. 2) many older video games that have a TV output. 3) Amateur Radio still uses NTSC video on 435 Mhz and up if you're interested. You can look at the outputs with this. Modern digital, some HD surveillance cameras, etc.? Nope, although it might be interesting to see what the scope can make of the signals.? I do have a 1910 digital pattern generator, and a pair of Hitachi scopes, NTSC and Vector.? Needless to say, I have some old video equipment around, one way or another.? Currently, all that is used are the older surveillance things.? When I was making TV cameras and playing with video, I'd have killed for some of this. Harvey On 11/27/2020 3:19 PM, Roy Thistle wrote:
Hi All: |
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Re: 528A TV waveform monitor.
Roy,
If you do any standard-definition TV (SDTV) work - such as converting older videocassette or other SDTV recordings to DVD, both a waveform monitor and vectorscope would be useful. A timebase corrector might also be helpful. All of this stuff can now be obtained at relatively low cost. But I don't know of non-SDTV uses for these items. It's too bad because they are great instruments. I had a Tektronix 1900 and then a 1910 TV signal generator. These had digital signal generation but converted to analog output for driving monitors and the like for testing. Tektronix had quite a product line to support the television industry. Tektronix equipment (along with Grass Valley Group which Tektronix acquired) was likely in almost every TV studio in the US. I think the huge 2" quad video machines came with a Tektronix waveform monitor and vector monitor installed in them, at least the vintage RCA and Ampex ones I have seen did. There must be some collectors or users of SDTV stuff out there. I have seen prices of the old Sony U-Matic machines (the studio ones) sell for higher prices than one would expect (the broadcast version of the Sony U-Matic machine - the BVU-950 - sells for over $2000). Even the Sony BVH-3100 one-inch C-format machines sell for over $1000 (on eBay) and shipping for these things would be a quarter to half of that cost. Steve H. On Fri, Nov 27, 2020 at 3:19 PM Roy Thistle <roy.thistle@...> wrote: Hi All: |
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Re: worst condition Tektronix scope?
Richard Steedman wrote:
The color of the smoke is VERY important: it tells you whether or not we have a new Pope. -- Jeff Dutky |
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Re: There is no good time to be SICK
Dennis,
I am glad you recovered and were able to enjoy Thanksgiving food. My wife and I stayed home as well but we did a Zoom get-together with family. Not as much fun as an in-person event, but better than complete isolation and a lot better than gathering in unsafe conditions. COVID-19 can first present with GI symptoms. Did you get tested or has the fairly rapid (I'm sure not rapid enough for you) resolution of your symptoms been your indicator that the infection was not COVID-19? I ask because my colleagues have seen some patients (mostly pediatric) who had only GI symptoms and their parents' first thought was "just a GI virus", but because the pediatricians have been alert to atypical symptoms were tested and were positive. The importance of this was then keeping the kids out of school (which had resumed here) until they tested negative and to test their parents as well. You don't have tell me anything more about your medical history - I don't want to be nosy. Thanks for all the work you have done getting copies of Peter Keller's book. I hope your wife can stand the wait until "elective" surgery can be resumed. I know what this is like - we shut down all elective surgery during the first COVID wave and it delayed many procedures. For people in pain but whose surgery was considered "elective", this was a terrible waiting time. Best wishes to both of you. Steve Horii On Fri, Nov 27, 2020 at 3:51 PM Dennis Tillman W7pF <dennis@...> wrote: My apologies. I sure my absence the past 4 days has caused some concern. I |
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Re: 528A TV waveform monitor.
On 11/27/2020 3:19 PM, Roy Thistle wrote:
My question is... what do I (What can I) do with it?...I know itis/was intended for monitoring the NTSC television broadcast signal. You might as well ask "what can I do with a buggy whip?" You can monitor NTSC video waveforms. That is all that it is useful for. Back in my days as Chief Engineer of a small commercial NTSC TV station I used two Tek 528A waveform monitors. I had one on the bench, which sometimes was dragged into the field, and one in master control. Next to each was a Tektronix 1420 vectorscope (a different type of buggy whip). -- Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA |
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Re: worst condition Tektronix scope?
I hope you pointed him to TekScopes and TekWiki.Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: stevenhorii <sonodocsch@...> Date: 11/27/20 10:48 AM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] worst condition Tektronix scope? There are a few very promising young people who are very interested though.I purchased a Tek 7844 on eBay - it was described as fully working. When Isaw where the seller was located, I contacted him and he gave me hisaddress - it turned out to be about a 45-minute drive away, so I went topick it up. To my surprise, the seller turned out to be a high schoolstudent! He has been interested in electronics and had (until COVID-19stopped that) working in a local calibration lab where he had access to awide range of bench test equipment.I met him and his folks and was very impressed by his interests. In otherrespects, he¡¯s like other teenagers - rides a mountain bike (he sent somevideos to me and he¡¯s not just riding around some flat terrain) and goeshiking with friends. But, he also has mastered 3D printing and he and hisfather built a shop he can work in.I decided to gift him a number of Tek scopes that had been sitting instorage - either because they had problems or were just not what I neededand I just don¡¯t have the time to fix the non-working ones. These included7854s (only one of which worked at the time), a 7904, a 7104, a 454 (whichworked). He and his family came to pick them up (I told them they wouldneed a large SUV or a pickup truck - they have the latter). Within a coupleof weeks, he had two of the 7854s working and knows the problem in thethird (he found problems with the CPU board and the one that had beenworking for me did not work when he powered it up). I told him he shouldfeel free to sell them when he¡¯s done fixing them so he can help fund hiscollege tuition fund. The 3D printing? One of the rear feet of the 454 wasbroken, so he 3D printed some. I think he may have offered them for salethrough this group.He wants to go to MIT and I was happy to write a recommendation letter forhim.A very impressive young man and he has the interest, promise, and skills toestablish a solid career in electrical engineering and will likely continueto rescue and restore vintage electronic equipment as a ¡°hobby¡±.Steve HoriiOn Fri, Nov 27, 2020 at 09:54 greenboxmaven via groups.io <ka2ivy@...> wrote:> For decades I have taken equipment that was discarded in disgust or> stored horribly and restoring it to operation. Initially, it was because> of poverty, now I get great enjoyment from rescuing it from the dumpster> and solving the puzzle of it's problems.? In 1971 I had returned from> duty in southeast Asia to? Griffiss Air Force Base in Rome, New York to> finish my term. Having worked on some neat stuff, I was interested in> having some of the rigs for my own. At that time, a Tektronix 524 would> cost $200.00 or more, and a Collins R-390 receiver would be $500.00 .> Once I got to the base, I felt certain there would be surplus stores> around, and there were, in nearby Utica.? Enroute to one I had been told> about, I noticed piles of gear out in the open in the heaped ruins of a> burned building. Some of it was totally wrecked, but most was a bit> smoked up and covered with dirt and ashes. The owner? was delighted to> sell us anything we wanted from the ruins for very low prices. I got an> R-390 for $15.00, quite literally half buried in the ground, and a> friend with me got a 535 scope that was just about as bad for the same> price. After an initial stop at a self service car wash to get the worst> of the dirt and ashes off, we both spent many evenings and a few> weekends, and a good amount of penetrating oil and contact cleaner,> dismantling and cleaning the rigs. Manuals were easily obtained, I> worked in the radio shop and my friend had a connection in the> instrumentation lab. We were both very surprised and impressed at how> well they turned out physically, indeed good enough that some of the> lifers and officers gave us a lot of crap about having "misappropriated"> them.? Fortunately, we were both returnees from the Vietnam theater, and> knew what to expect and do. We had receipts from the surplus store and> pre-restoration photos.? The lifers then just shrugged in disappoinment> and left us alone. We both enjoyed the fruits of our work, I kept the> R-390 for years, and my friend used the scope for digital experimenting> and very early computer crafting.? What frightens me today is so few> young people having the interest or ability to do such work, and the> priceless learning and skill they could gain from doing so.>>??????? Bruce Gentry, KA2IVY>>> On 11/27/20 5:59 AM, Richard Steedman wrote:> > Have you read the full description of this guy's scope?> > "i plugged it in but it started smoking (white smoke) so i turned it off"> > "i will take the side panel off tomorrow and take some pictures"> > Those pictures should be a sight to behold!> >> >> >> >> >> >>>>> >>>
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Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.
Harvey and Bill,
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Yes - I've tried that trick. For small gyros it works. Gyros with electric spin motors tend to draw the most current at startup as do most motors. After that, the current usually drops quite a bit. Some of the 400Hz gyros use two-phase power. The usual trick is to put a capacitor across the two spin motor inputs - it provides the phase lag for the second phase. I have NOT tried this, but I have seen some gyros - usually the small ones that are about one-inch in diameter and three inches long and almost always rate gyros - that had a phase-splitting capacitor already soldered in place. This white paper describes a basic 2-phase power supply for gyro spin motors: I was fortunate - at a hamfest years ago, I picked up a couple of Abbott Transistor Labs inverters. These took 24-28 VDC and output AC 400Hz single phase at up to about 2 amps. Not enough to run a large gyro, but enough for the smaller ones. I even ran a fairly large gyro - a Honeywell rate gyro - with one of these. They do need a heatsink. I sometimes do an eBay search for "Behlman Invertron" as they made some very useful frequency converters - 115 VAC to variable 400Hz AC. Some were variable frequency and some versions also had single to three-phase output. They tend to be expensive (and heavy for the higher output ones) and I never managed to find one at what I thought was a reasonable price. Some versions had interchangeable plug-in oscillators so you could run even higher frequency AC devices (some gyros use 800 Hz - the Apollo program gyros ran with 800 Hz, 2-phase power). There are currently a couple of Behlman Invertrons on eBay, though they are not cheap. If you can find them, some of the WW II and even early missile (Nike) gyros ran on DC (24-28 v). Those are fun to run up. However, I've had some for which the bearings almost certainly were bad - they were very noisy when running and spin-down after power was removed was quite fast. Likely why they were surplus. Years ago, a surplus dealer on Canal Street in NYC sold me a WW II Bendix vertical gyro. It was a 400Hz gyro and he told me I could run it on 60Hz AC by putting a current limiting incandescent lamp (no choices - there were no LED lamps then) in the power circuit and running at a lower voltage via a Variac. I did not have the guts to try it, but I do know those who did and said it works, but you will not get the gyro up to full speed. Messing about with gyros can lead you down a deep hole much as getting fascinated by Tektronix equipment and then desiring to get some (plus spares "for parts" and all the manuals). Now you can get fairly accurate gyros made using IC fab techniques - the MEMS units. These things live in smart phones and tablets now. These plus GPS have radically changed inertial navigation. Fun stuff, though. Steve H. On Fri, Nov 27, 2020 at 1:52 PM Harvey White <madyn@...> wrote:
Hi-fi amplifier of sufficient output capability driven by a sinewave |
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There is no good time to be SICK
My apologies. I sure my absence the past 4 days has caused some concern. I
have been sick. Tuesday morning I was in bed with what I guess was a stomach flu. The next two days alternated between bed rest and emergency visits to the bathroom. My worst fears (COVID) were unfounded and by Thursday afternoon I was definitely feeling well enough to taste some of the Thanksgiving dinner my wife made for the two of us yesterday. Thanksgiving is a national holiday in the US and some other countries. It began as a day of giving thanks and sacrifice for the blessing of the harvest and of the preceding year. This year it has taken on much greater significance because the virus has prevented us from celebrating it with friends and family. I don't know if it was because I hadn't eaten anything in several days or because she is a wonderful cook but that was the best tasting food I can ever remember eating. PayPal has once again been an enormous source of frustration for ME. That frustration got the better of me by Monday and I know it was apparent in some of my comments which I regret. But it appears YOU have found ways to work through the PayPal issues I was struggling with and I appreciate that. Marian reports that almost $3,300 has come into our PayPal account for Peter's book. That is a very good indication that almost everyone has paid. My mail box is flooded with over 400 new emails right now. It will be necessary for me to triage them. Please be patient. I allowed plenty of time for all of the payments to arrive. Priority will be given to matching the payments for Peter's book to the orders I have. I will be very busy in the next few days as I do all of this. I hope you are all taking precautions to stay safe from the virus. We are in our family. The virus has exploded in the US over the past few weeks. Hospitals are at near capacity. Hospital staff are exhausted from dealing with the virus for the past 7 months. I can only watch in horror as people are packing into airports to travel during the holiday season and packing into stores to buy gifts. Part of my time I have to help Marian with our five Golden Retrievers now that she can barely walk them. She is waiting for elective surgery to replace her hip. Those surgeries are being postponed by hospitals so they can deal with COVID cases. She is in constant pain when she stands. Dennis Tillman W7pF |
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7L5 sweep problems
This is a continuation of a serious 7L5 restoration started last year. Here's where I left off:
/g/TekScopes/topic/31248178?p=Created,,,20,2,0,0::recentpostdate%2Fsticky,,,20,2,0,31248178 Since the recent 7A42 battery issues discussion, I've been re-looking at my "smart" plug-ins to make sure there are no battery issues. The 7L5 does not even have a microprocessor, so no battery. While looking, I figured maybe I'd take another shot at this repair project, and see how it is. I managed to find some of my old notes on this, but still some are missing. I fired it up to refresh my memory, and recalled some of the issues. I replaced a suspect part in the trigger section of the sweep board, and it now seems closer to proper operation. The problem where I left off was no video signal, but I think the basic problem is mostly in the sweep generator. I'm not getting proper horizontal sweeps with any settings. As I understand from what I've read in the manuals, if the sweep doesn't run right, neither does most of the system. I've been doing tests, piecemeal, by taking all the ^%*#$^ apart, tacking wires onto various nodes, then putting all the ^&$#@% back together, and popping it in the mainframe for checkout and measurements. So far I've confirmed the seep reference voltage is present, and the time/div knob probably is working correctly, since the reference voltage changes from -2V to -4V at certain settings as it should. Also, the sweep out from the integrator is wrong - it's sort of a triangle wave pulse that seems too small (about 5-7 volts peak versus the proper 8 or more), and not often enough. Last time open, I wanted to tack onto the data lines for the timing resistor selector (HC4051) and sweep gate signal, but they weren't accessible without taking it apart deeper. These will be included next time. Also, the "dot" has disappeared, and doesn't show in any settings. Earlier on, it did show, but was stuck on, and flakey in position As it is now, all the front panel functions seem to do something, and all the readouts seem to work. When A and B storage are off, there's the real time baseline sweep displayed at the bottom, but it's at a constant, slow rep rate (flickering) and velocity, unresponsive to the time/div setting (which is not read out on screen anyway, so can't tell if it's actually trying to do anything), except that it disappears completely at some time/div and span settings, where I think various modes are supposed to change. Manual scan does function, but it's dot flickers too, at the same rate. As I understand, in manual sweep the actual sweep runs at some higher rate to keep things working, and the horizontal signal is instead from the pot. So, I'm pretty sure the sweep generator or something related is way out of kilter. It's tricky to figure out because the behavior of the sweep is modified by various operating settings too, so something elsewhere could be the real problem. I've read a lot in the various manuals, and getting better understanding of what's supposed to be going on. It is a complicated beast, with a lot crammed in there. Also, as I previously admired the way some of the plug-in is put together, I now hate the way other parts are. It's a real PITA to disassemble it below a certain level, or to access certain things, especially that sweep board, where most of my work is now focused. The other problem is that every time it has to be taken apart, it's more wear and tear on the innards, and risk of further damage - especially if I eventually have a tantrum and destroy it worse than I got it. So anyway, if anyone has experience with the 7L5 and diagnosing these issues, please advise. Ed |
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Re: worst condition Tektronix scope?
Wonderful! Now, we just need a million or so more of them. About twelve years ago, a large local auto dealership had a job fair. Entered apprentices would start at $17.00/hr plus full medical care and union benefits. They had ten jobs, and filled two of them. Clerical and financial jobs started at minimum wage with very sparse benefits, the applications were over twice the number of openings.
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Bruce Gentry, KA2IVY On 11/27/20 1:48 PM, stevenhorii wrote:
There are a few very promising young people who are very interested though. What frightens me today is so few |
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Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.
"Sufficient output capacity" is unlikely. Those would probably need several amperes. Are you sure about the specs? The military aircraft I'm familiar with used 28V DC and 400 Hz 110 VAC 3-phase. I don't think I've seen anything running at 400 Hz 28V.
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Steve Hendrix At 2020-11-27 01:52 PM, Harvey White via groups.io wrote:
Hi-fi amplifier of sufficient output capability driven by a sinewave generator sitting at 400 Hz? |
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Re: Delay Time Position Vernier
Remember that a common FG will not be all that accurate in frequency, or have great edge speed. There are types that do, but not so common. The easy way is if you happen to have any kind of digital signal generators or sources that are accurate. You can also slap together simple DIY sources, with basic parts like a XO clock module, followed by various dividers. Use 74HC logic for up to about 20 MHz. Beyond that it gets a little more complicated.
Ed |
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Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.
He may need three phase. There are inverter control boards on Ebay that
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shouldn't be too hard to hack for 400 Hz. On Fri, Nov 27, 2020 at 1:52 PM Harvey White <madyn@...> wrote:
Hi-fi amplifier of sufficient output capability driven by a sinewave |
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Re: Tek Glass Tracing
Since you can see right through everything, it should be easy to check for sure which lines are actually broken open - then you don't have to guess from appearance and do unnecessary repairs. Ohm out each line end to end, while flexing (not excessively) all the stress zones, and mark the ones that are bad. It looks like the traces are metal strips, made the same way as those that would be etched on a circuit board, so yes, quite thin. If you can peel back the top plastic layer without wrecking the lines, then you can dab some silver goop to bridge the breaks, then check continuity after it sets up (it won't be conductive until dried/cured). You can get silver board repair inks and goops from many places - it's for this kind of purpose, on metal or carbon runs. It won't be as durable as the original, so be careful to not flex it too much on re-installation.
Ed |
Dale H. Cook
Michael A. Terrell
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