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Re: Tek 2465B Bezel Removal
Okay, I think the analog would be more useful possibly in trouble-shooting,
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but I am so experienced in the TDS3000 series, that I love trouble-shooting with it, plus I know the equipment so well that I work on, I am rarely stumped anymore. I get out of the habit of really trouble-shooting anymore. i worked with the 2430A a little this morning and I was wrong with my original assessment. i had just looked at in t a hallway before putting it away. With a scope probe, it really isn't too bad. The trace adjustment take a little to get used to. It passed self-diagnosis. I just need to spend time with it. Would it be worthwhile to put on EBAY if I decided to? I really don't have a lot of selling experience and with me having a business, I would have to pay taxes on whatever it sold for and then the government gets about half, so it really wouldn't be worth the effort. Anywho, back to work. Thanks for the response. Dave On Thu, Nov 1, 2018 at 11:49 AM Harvey White <madyn@...> wrote:
On Thu, 1 Nov 2018 11:32:24 -0400, you wrote:" The 2465B does (should!) have measurement cursors for time and/or- |
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Re: Tek 2465B Bezel Removal
On Thu, 1 Nov 2018 11:32:24 -0400, you wrote:
" The 2465B does (should!) have measurement cursors for time and/orThey aren't that bad. They can do well. Not really useless, IMHO. Probably is, you might be surprised at what it will do, or can do. There are things analog scopes will do that digital scopes won't, or don't do quite the same way. I have the 7000 series, a 2430A, and a TDS540A, and the digitals get used for one set of things, the analogs get used for another. Neither technology is best for everything. Harvey
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Re: Tek 2465B Bezel Removal
Craig,
Thank you kindly for those detailed instruction, which I have printed out. Perhaps later today, I will follow them and get that puppy cleaned out and generally look inside for cap leakage. Dave On Thu, Nov 1, 2018 at 10:54 AM Craig Cramb <electronixtoolbox@...> wrote: The knobs don¡¯t have to come off. This is how I do it all the time. I |
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Re: Tek 2465B Bezel Removal
" The 2465B does (should!) have measurement cursors for time and/or
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amplitude but you have to enable them to see them. Nice dumpster find! " Yea, I found them, before putting it aside this morning to do paying work - lol. The 2465B seems like a really nice analog scope with a very nice CRT. I just use TDS3000 series on a daily basis. Also in the dumpster find was what appears to be a useless very early attempt at a digital controlled scope, the Tektronix 2430A. As far as I can tell, it works and is in very good shape, and a great CRT, but wow, what a slug to operate. It's another one that I am probably too dumb to operate - lol. Heck it even has GPIB. I love to write software to control GPIB equipment. I don't know if that 2430A is worth my time to add it to some of my utility or calibration programs. I grew up around the round screen beautiful boat anchors (500/600 series?). That's all my tech school had in 1979. On the job I grew up with the Ultra-modern (for me at the time) 465. A 465 traveled with me all over the county. When its CRT was replaced, I even had the beautiful blue phosphor. My next scope in the 90's was a 2247A. After that, I went right in to the TDS3000 series. I haven't used an analog scope in years. I still keep a 465 on the bench but it has flaky cam switched in the amplifiers. even though it may never get turned on, I may just replace the 465 with the 2465B. If I did it honor and service, I would open it up and re-cap it. I just know if I have the energy to do that. i also dumpster-ed a 520A and 524A and another 52x. All broken (power supply and probably cap issues on the ACQ boards). They are beautiful when working. I would love to get one of those working, but I doubt I will ever take the time. i might even be willing to pay to have one of those fixed to use. Anyway, I digress.... Dave On Thu, Nov 1, 2018 at 10:15 AM n4buq <n4buq@...> wrote:
Hi Dave, |
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Re: Tek 2465B Bezel Removal
The knobs don¡¯t have to come off. This is how I do it all the time. I usually take the case off when doing this but the scope needs a front cover which you may not have. But it if you set the face on carpet and carefully and don¡¯t put alott of pressure on the controls of the front panel. Remove the rear screws 4 #20 torx and 2 #15 torx if all screws are still in rear cover. Then slide the case off the back. Then set on a table with the front Basel just off of the tables edge now or later as in this info. Take a small screwdriver and get under the edge of the strip on top of front bezel and pry it up moving along from one end to the other. Do this carefully as the little plastic tabs will come out . Then you now have access to all 8 #10 torx screws. 4 on top and 4 on the bottom. Then set the front just off the edge of the table and rock it easily to pull the entire assembly forward. The knobs and the knob retainers will cone off of the potentiometer shafts all together. Just work it forward easy mainly pulling on the screen side a little more. Then when putting it back on. Get the front started on the potentiometers, might have to move the knobs bu turning them a bit to get it to line up the carefully work the front Bezel back on. Then leave the bezel cover strip off reinstall the case and back then put bezel strip back on.
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Removing knobs is very hard and 80% of the time they will break there internal clips. Craig On Nov 1, 2018, at 8:52 AM, David Kuhn <Daveyk021@...> wrote: |
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Re: Tektronix 067-0625-00 Peak to Peak Detector Battery
On Thu, 1 Nov 2018 07:10:19 -0000, you wrote:
Same thing with logic analyzer probes, scope probes, and anything inBe aware that the CG5000that?) general. Ran into a bunch of P6201 active probes that were "decommissioned" by cutting of the 40 dollar LEMO connectors. Idiots..... Harvey
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Re: Tek 2465B Bezel Removal
Hi Dave,
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The 2465B does (should!) have measurement cursors for time and/or amplitude but you have to enable them to see them. Not sure the exact buttons that do that but it should be easy enough to find that info. Nice dumpster find! Thanks, Barry - N4BUQ I don't know if this would be scope with capacitor issues or not. At this |
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Tek 2465B Bezel Removal
I got a 2465B, 400MHz, while dumpster diving a while back. It seems to work perfect. I do not have a lot of use for an Analog scope, (especially w/o GPIB) but if I decide to sell it on EBAY, or even if I decide to use it for trouble-shooting, I need to clean it up. There is some dried liquid behind the BLUE crt filter (maybe cat pee).
Beside the four torx screws on the bottom, how to I take the bezel off to clean it? i remember reading where it is real easy to break the knobs removing the bezel. I assume only the four knobs under the CRT need to come off? I don't know if this would be scope with capacitor issues or not. At this time, it seems to be working well. It does not seem to be the easiest scope to get used to its operation, especially the measurement functions. I don't think it has cursors; I be more prone to keep and use it if it did. When cleaned up, without re-capping (don't know if it needs it or not), what kind of value is it, if I were to sell it. The effort of finding/making a good double-boxing system may not be worth it. Thanks kindly, Dave |
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Re: 425 Mil vertical module needed....seeking
Hi Jack,
Bert Haskins... he's replied to your topic, see msg reference below. /g/TekScopes/message/152031 Most of his message is quote from previous messages... And his reply is a two liner, at the end. Rgrds, Fabio |
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Re: 577 retrace problem
On Thu, Nov 1, 2018 at 08:31 AM, Craig Sawyers wrote:
The explanation has been discussed here before, see for instance Craig's comment in this message:2) John's final conclusion is as follows: The fact that this separation oftraces happens mostly attheat top of the collector /g/TekScopes/message/82538?p=,,,20,0,0,0::Created,,curve+tracer+loop,20,2,20,7650083 Albert |
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Re: 577 retrace problem
Hi Fred,
I glad you asked about this because at times I find this effect quite annoying and at other times it seems like all the curve tracers I have owned (2 x 575s, 1 x 576, 5 x 577s) have displayed it. By now these loops look so familiar that I would have said your 577 (or 576, or 575) is behaving perfectly normal. In his original design for the 570 Vacuum Tube Curve Tracer, John Kobbe rectified the power line to use for the plate sweep voltage. In the 575 Transistor Curve Tracer he used the same concept for the collector sweep voltage. If you look at the waveform on the collector you would see a full wave rectified sine wave. I suspect your 577 isn't the problem at all. I think what you are seeing is due to a combination of the transistor itself and to the way John Kobbe used a rectified sine wave for the collector sweep. But there are actually two plausible explanations: 1) My explanation is the transistor die is experiencing rapid heating and cooling due to the collector voltage across it and the collector current going through it. If this theory is correct then transistors with very small die sizes would have larger loops due to the heating and cooling and conversely power transistors with large die sizes and metal cases (like TO-3) would have small loops or no loops at all. Also, if die heating is the cause then the loop is going to be wider vertically at the peak of the collector sine wave which is all the way at the right side of each step's trace in the photo you took. But the loops ae larger on the left side of your photo. So something is wrong with my theory. Next I asked John Addis for his theory. Initially John also though die heating was a possible cause. but after thinking about it he decided it couldn't be die heating and he had a much better explanation which fits the waveform you are seeing on your curve tracer. is what he thought at first: Both heat (¦¤Vbe) and Ccb cause effects in this direction, assuming that the upper part of each trace (above the loop) is associated with the decreasing part of the rectified sine wave. However, the fact that it seems to be the same magnitude at low and high Ib, argues for Ccb getting into the base current. 2) John's final conclusion is as follows: The fact that this separation of traces happens mostly at the part of the collector sine wave with the most rapid change of voltage (not at top of the collector sine wave which corresponds to the right most point on each trace) pretty well clinches the Ccb explanation. John Kobbe's original concept of using the rectified sine wave from the power line became the collector sweep. Where the sine wave is rising from zero toward its maximum, the rate of change in the collector voltage ¦¤V/¦¤t is the greatest. This changing voltage results generates a current flowing from the collector to the base through the Collector to Base capacitance, Ccb. This Ccb current adds to the base current from the step generator causing the trace to increase a small amount (move up on the CRT) creating the upper part of the loop in each trace (compared to a capacitance-less transistor). Once the rectified collector sine wave voltage passes its peak and is coming back down to zero the effect is reversed and the Collector to Base capacitance results in a small opposite current going into the base which subtracts from the base step resulting in the lower part of the loop in each trace. Since the collector voltage is the same for each base step each loop is the same whether they are the lowest trace or the highest trace on the CRT. To confirm Ccb causes the loops place two transistors on your curve tracer. The transistor with the smallest Ccb will have the smallest loop. Another way to prove this to yourself is to put any transistor on your curve tracer. Start on the 6.5V Peak Volts setting and a very large base step. The effects of the collector voltage generating a noticeable current in your base due to Ccb will be minimal resulting in no loops at all. Now switch to the highest peak voltage the transistor can handle and notice that as you decrease the base steps, and increase the vertical sensitivity to compensate, the loops grow larger. What John is saying is that Ccb, the capacitance between the collector and the base, causes current to flow into the base causing the loops, and not die heating. In addition to Ccb, the collector sweep voltage and the base step size also contribute to the loops. If the 575, 576, and 577 curve tracers used a sawtooth collector sweep you would not see this looping. Dennis Tillman W7PF The way to test this is to wire up a cascode arrangement of two transistors, and curve trace that. Since the whole rationale of a cascode is to mitigate the effects of Ccb, the looping should disappear. Craig Dennis and Craig, thank you so much much for the very informative answers. I used a TO3 BUX48A for my tests. The comparators at the AC collector voltage provide a pulse at 90 degrees. You think it would be possible to feed this in a flipflop and blank the trace from 90 to 180 degrees? Best regards, Fred |
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Re: Tektronix 067-0625-00 Peak to Peak Detector Battery
and another physical design that Dave Partridge didand I do still offer it. For details please refer to < > where you'll find full details of the design, construction and test results. Dave -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Craig Sawyers Sent: 01 November 2018 07:10 To: [email protected] Subject: Re: [TekScopes] Tektronix 067-0625-00 Peak to Peak Detector Battery Be aware that the CG5000a wire, why'd you need that?) ((because it has stuff attached to it that the gadget needs?))What receivers do when a company goes bust is make a pile of electronics to sell, and put all cables or anything that looks like a cable, in a large bin and sell that as a single lot. Since a (detachable) levelling head looks like a cable, into the bin it goes. So just about every SG504 for sale anywhere is minus the levelling head. Hence Ancel's replacement head (and another physical design that Dave Partridge did). Earlier Tektronix levelled generators had a captive levelling head, so don't suffer the same fate. Craig |
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Re: My 2465B has arrived + A5 Board leaky caps cleanup
Alex,
If the scope has the optional CTT board then it is very simple with your serial number scope to enable the external frequency input option (1E) by simply moving the coax cable for rear BNC jack labeled Probe Out over 1 position on the CTT board connector. Manuel |
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Re: 577 retrace problem
Craig Sawyers
2) John's final conclusion is as follows: The fact that this separation of traces happens mostly at What John is saying is that Ccb, the capacitance between the collector and the base, causes currentThe way to test this is to wire up a cascode arrangement of two transistors, and curve trace that. Since the whole rationale of a cascode is to mitigate the effects of Ccb, the looping should disappear. Craig |
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Re: Tektronix 067-0625-00 Peak to Peak Detector Battery
Craig Sawyers
Be aware that the CG5000that?) ((because it has stuff attached to it that the gadget needs?))What receivers do when a company goes bust is make a pile of electronics to sell, and put all cables or anything that looks like a cable, in a large bin and sell that as a single lot. Since a (detachable) levelling head looks like a cable, into the bin it goes. So just about every SG504 for sale anywhere is minus the levelling head. Hence Ancel's replacement head (and another physical design that Dave Partridge did). Earlier Tektronix levelled generators had a captive levelling head, so don't suffer the same fate. Craig |
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Re: My 2465B has arrived + A5 Board leaky caps cleanup
Chuck Harris
Hi Alex,
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The design of the front panel is such that all of the displays states are in registers that get strobed whenever anything is changed on the front panel. That shows up as a brief flash of all lights. The 2465B uses 74F logic for those registers, the older 2465 used 74LS logic, and fairly dim LED's. The blink is scarcely noticeable with the older 2465. The 2465B uses much brighter LED's, and the blink is quite apparent. With 350MHz bandwidth comes a lot of ambient noise. Cut the bandwidth, and you will cut the noise. That is why the scope has the 20MHz bandwidth limit switch on the front panel. Working amounts of power supply ripple are not generally noticeable. Large amounts, usually cause erratic operation. An example of erratic operation would be trigger jitter. The 2465B is not a frequency counter, and the A5 board's 10MHz reference has nothing to do with sweep or frequency accuracy. The way the 2465 family creates its sweep is by using a miller integrator, and precision integration capacitors. The way it measures frequency is rather convoluted, but depends entirely on the sweep accuracy. Think of it this way, the sweep is generated by charging a capacitor with a constant current. It is correlated to both the graticules, and the cursors during calibration. The frequency measuring method uses the trigger hybrid and a DAC to measure the zero crossing points of the waveform, and uses the delay sweep to measure the time between the zero crossing points. The CPU then performs the inversion, and the display shows that number as the frequency. It is not a frequency counter! It is standard practice of most sellers to remove all calibration stickers, and stickers showing previous ownership before the sale. Although I don't sell a lot of scopes, when I do, I blow out the dust from the inside, clean the outside, and the CRT, make any repairs, and calibrate the scope, complete with zeroing the counters. It would look as you are describing your scope, regardless of how old it really is. If I cannot repair it, and clean it up to that degree, it becomes a parts source. According to Manuel Maseda, Option 46 is the military version of the scope (OS-288/G) that includes option 10 (IEEE-488), and 2 probes. -Chuck tekscopegroup@... wrote: On Tue, Oct 30, 2018 at 01:11 PM, Chuck Harris wrote:Hi Chuck, this certainly makes a lot of sense. Thanks for clarifying it, never heard this simple and logical explanation from anyone else, other that people being very happy when they see low numbers on those counters on a newly acquired scope. This one does not have any past cal stickers at all, so wonder if it ever was calibrated after being purchased. |
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Re: 425 Mil vertical module needed....seeking
Hi..all interesting ...who's Bert?...I haven't seen anything from him.....My regards
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-----Original Message-----
From: Fabio Trevisan Sent: Thursday, November 1, 2018 10:59 AM To: [email protected] Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking Hi Jack, The google translations are perfect, both in Portuguese and Spanish. Only the expression "mileage" in Portuguese and in Spanish are not usually used for anything else than vehicles. For the strict meaning of "usage", we just say "uso" (which is the exact translation of usage). In view of the answer from Dinos (thanks Dinos for correcting my assumptions), the contact with this seller in Brazil may not yield anything fruitful, as this guy seem to be a lonely wolf (he doesn't seem to have anything else than this 455 parts... and since the parts differ from the AN/USM 425 that you have, those parts probably aren't interchangeable with yours. But Bert already chimed in that he has a NOS 465M module... so I think you already have a good lead. About Tektronix, vs anything else... I also have mixed feelings about it... In my first job in the 80s, most of the scopes were Philips and I loved them... and we had one Tek 465 which I was never comfortable to work with. I found back then that arrangement of the time base knobs clumsy and awkward to use, and that the lack of an ALT delayed time base was really a big weakness... and I still think it was... I really don't know how Tek got away with selling so well the 46x line with that useless "Mix" mode, when they had earlier designs which already had the "ALT" time base. To some extent, some of that awkwardness in using the Tek scopes have disappeared as I became used to its "User Interface", and I learnt also to appreciate that many of those features that I took for granted on the Philips scopes were actually invented and appeared first on some Tek scope many years before (which I didn't know back then). Today I own a Tek 7623A with 3 plugins, and a jap scope, a 60MHz triple trace Kenwood scope... And I like both very much. The Kenwood is very powerful for its relatively simple design (there are no double sided PCBs!). Wish you luck with your 465M Rgrds, Fabio On Wed, Oct 31, 2018 at 06:22 PM, Jack wrote: -- Jack |
Roberto
Craig Cramb
Fabio Trevisan
David C. Partridge
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