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Test Fixture Name
Dick
I am looking for one of these small boxes (around 1" X 1" X 2-3")
that had a Male BNC on one end and a Female BNC on the other end. Tektronix made them probably 40 to 60 years ago. What would be a correct name to do a search on ?? Small Box just doesn't get there !! Thanks, Dick, W1KSZ |
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A few hard to find, minty service manuals available
walter shawlee
After winding up stuff day (season) at Sphere for the year, I found a stash of almost mint Tek service manuals for some of the scopes we had on for stuff day. Before I post them up to the page, I thought I'd mention them here, in case anybody is looking for them. All of these are big and HEAVY, any one, $25.
Tek 465B 100Mhz Scope (below s/n B60K) Tek 465B 100Mhz Scope (above B60K) Tek 305 portable DMM/Scope Tek 336 Digital Portable Scope Fluke 8250A Digital Multimeter Fairchild EMC-25 Interference Analyzer If these can help you, please advise off list. I also found 321A and 310A printed manuals. The stuff event will be back for Christmas Season, and the page will get re-stocked in November, until then, you can still get anything left from summer until they are gone. all the best, and stay safe, no easy task right now if you are on the west coast. walter (walter2 -at- sphere.bc.ca) sphere research corp. |
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Re: Cleaning Leads of IC Chips (Tektronix Related)
If you've gotten the board out, I'd suggest using a hot air gun to heat the underside until you can pull it off.
As for cleaning the leads, you can try a solder sucker or solder wick or both, but there will always be a thin layer of solder left on the pins. |
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Re: Help Troubleshooting 466, No +15VDC
I've done that ... once. I had a main board for a Radio Shack Model III computer with ONE shorted 0.1uf bypass cap out of about 50 or so. 5V at 10 amps cleared it in less than a second.
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Vince. On 09/10/2020 02:16 AM, Stephen Hanselman wrote:
Actually my partner used that procedure regularly, I think it¡¯s a bit drastic but he swears by it. --
K8ZW |
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Re: Please help with TDS340A
31.5 Khz sounds like something generated by the display.? You could disconnect the display power, use an external display, and see if it goes away.? Possibly a bad filter capacitor in the display itself.
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Harvey On 9/9/2020 2:37 PM, James wrote:
HI all, |
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Re: Help Troubleshooting 466, No +15VDC
On 10. Sep 2020, at 15:14, Chuck Harris <cfharris@...> wrote:Exactly! I have such a camera for some years, it became my most efficient troubleshooting tool as soon as my nose rings the bell... and even beyond that. Recently I was checking an HP function generator that blew the fuse. Fuse replaced, cautious ramp-up on the variac with the IR-cam in the other hand, one of the rectifiers quickly made its "streetlamp"... cheers Martin |
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Please help with TDS340A
HI all,
I am out of my depth, no question but I'm going to ask and see what you guys think. I have a TDS 340A which has behaved well but now has some kind of switching artifact that makes it impossible to use. There is a pulse at 31.5kHz which can be seen clearly with a coiled wire attached to a probe and which seems to come from the front of the screen. This pulse is getting through either channel into everything I am trying to measure, I cannot tell how. If the probe is grounded the signal is clean as you would expect, but every circuit I attach a probe to now shows this wretched pulse. Is this a result of some foolery on my part, a scope about to go on the blink, or something quite different? What can I do to try to fix it. I am no EE, just a basic hobbyist and unhappy with the idea of serious surface mount work - I will likely screw up worse than it is! I do have an old scope that functions in a manner of speaking which I could use to probe if anyone thinks I can achieve anything useful, or am I better off getting another functioning scope, or finding (where in UK) a person willing to try to fix it? Any and all help gratefully received! Many thanks James |
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Re: Help Troubleshooting 466, No +15VDC
Chuck Harris
Physically, tantalum drop capacitors have a lot of
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the characteristics of a fuse. The tantalum metal melts at a reasonably low temperature, and pops the capacitor's body, leaving a couple of bare wires sticking up in the air. IF, the circuit board traces can handle the current, the old capacitor will have revealed itself, and be ready for an easy top-side repair. Capacitors on the logic supply planes of a multilayer board clear most dramatically with this trick, but when it goes wrong, the thermal breaks blow too, and you may have to drill the short out of the board and put the capacitor elsewhere... or do without. I prefer a slower method, using an IR camera, and a middling amount of current to warm the offending traces, and the offending capacitor. They show up like little streetlamps on the IR camera's screen. -Chuck Harris Stephen Hanselman wrote: Actually my partner used that procedure regularly, I think it¡¯s a bit drastic but he swears by it. |
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Re: Mystery Pulse Generator
I'd guess that it's an instrument made for internal use at Tektronix. The unfinished rear panel (2 unused holes for GR connectors and the hand lettering support this suspicion) Also, the complete lack of a Model number and a serial number (not even a sub 100 S/N). It might be one-of-a-kind, built by an engineer for a specific project. The 3 prong power connector indicates that it is not ancient.
The 0.2 nS risetime is impressive, when compared with my R293 (1 nS, using an avalanche transistor). The R263 is probably much better in the pulse shape and width control department, however. |
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Re: 7D20 with unknown options or mods
Thanks Clark, Chuck. Very interesting. The leads to the CCDs don't appear to be connected to any of its DIL pins. They look like they are soldered directly on to the substrate. The SL92104 looks a quite complicated MCM affair. I'm not sure I want to go poking around there! I haven't been able to find a datasheet for the SL92104 chip. Any idea whether such a document exists? |
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Re: Strange Tek2440 issue
Your old capacitors are best tan new, sure!
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-----Mensaje original----- De: [email protected] [mailto:[email protected]] En nombre de Vince Vielhaber Enviado el: mi¨¦rcoles, 9 de septiembre de 2020 5:50 Para: [email protected] Asunto: Re: [TekScopes] Strange Tek2440 issue Ok, here's where I'm at. ALL of the electrolytics, except the two big ones in the back, have been replaced. I tested them and they were all good with very low ESR so I'll toss them in a box for now. Q870 and Q879 have been replaced. Had to order these. All resistors in the 5V Regulator have been checked and are all well within spec. The few small caps (.001uf) were also checked and are right on. Problem still exists. Before I was toying around with the idea of hanging an external 5V supply on it. I did try that last week and it did NOT do it and according to the meter on the supply, it wasn't really drawing much current from it - less than 100ma. Tomorrow I'll go thru the supply again and take more measurements, there were a few points I was looking at and couldn't remember if I checked them and if so what they were. So tomorrow I'll check them and take pictures and better notes. That's it for tonite. Vince. On 09/02/2020 02:50 PM, Siggi wrote:
On Wed, Sep 2, 2020 at 2:07 PM Vince Vielhaber <vev@...> wrote:I had actually done that last nite, but didn't have the parts layout --
K8ZW |
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Re: Mystery Pulse Generator
Dave,
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I'm sure you noticed - the faceplate and rear connector panel are all hand-lettered. A nice lettering job, but is this actually a Tek item? Maybe if the original silkscreened labels were worn too much to read easily someone re-lettered over what was there. Steve H On Thu, Sep 10, 2020 at 2:06 AM Dave Seiter <d.seiter@...> wrote:
On ebay, 362868002250; not sure what it really is- what caught my eye was |
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Re: Help Troubleshooting 466, No +15VDC
Actually my partner used that procedure regularly, I think it¡¯s a bit drastic but he swears by it.
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Regards, Stephen Hanselman Datagate Systems, LLC On Sep 9, 2020, at 20:50, Jim Ford <james.ford@...> wrote: |
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Re: Help Troubleshooting 466, No +15VDC
I'd suspect serious consequences on anything other than 2 layer PC boards, and even then....
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I think I'd prefer a, perhaps slower, method. Harvey On 9/9/2020 11:50 PM, Jim Ford wrote:
Maybe it does for shorted tantalum capacitors.? Not guaranteed to work on shorts inside the PCB.? Oh, it will show you where the short is alright, but that doesn't mean the short will clear or the PCB will be usable afterward.? Don't ask.... |
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Re: Help Troubleshooting 466, No +15VDC
Maybe it does for shorted tantalum capacitors. Not guaranteed to work on shorts inside the PCB. Oh, it will show you where the short is alright, but that doesn't mean the short will clear or the PCB will be usable afterward. Don't ask....
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Jim Ford ------ Original Message ------
From: "Stephen Hanselman" <kc4sw.io@...> To: [email protected] Sent: 9/9/2020 3:18:34 PM Subject: Re: [TekScopes] Help Troubleshooting 466, No +15VDC Our favorite way was to use a HP 2100 power supply 5VDC at 50Amps. Finds¡¯um every time |
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Re: Help Troubleshooting 466, No +15VDC
So what do you do to repair craters in the PC board?
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Harvey On 9/9/2020 6:18 PM, Stephen Hanselman wrote:
Our favorite way was to use a HP 2100 power supply 5VDC at 50Amps. Finds¡¯um every time |
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Re: Strange Tek2440 issue - SOLVED!
Ok, the problem has been solved!
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As Siggi said, "this makes no sense". He was right, it made no sense. On the inverting input of U870A is the 4.99V reference. It measured 5.14V and the non-inverting input measured 5.15V (Fluke DVM). The theory of operation mentions that the 5V regulated supply is the same as the 8V regulated supply. So I made some comparisons and saw that on the 8V there was a 0.10V difference between the inverting and non-inverting, not so with the 5V. As I mentioned before, I lifted one lead of both resistors (and a couple of others) and they were all within spec. Strangely enough, it took another 6.8K across R875 (a 6.19K) to drop pin 2 (inv) on U870 to 0.10V less than pin 3. Measuring R875 again (with a lead lifted) it was giving a new value. Both resistors (R875 and R877) are now on order. Thanks!! Vince. On 09/08/2020 11:50 PM, Vince Vielhaber wrote:
Ok, here's where I'm at. --
K8ZW |
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Re: 7D20 with unknown options or mods
Richard,
I found some clues about the little board on the Timebase board. It is named "ERD Shift Adjust." ERD is a digitizing mode called "extended real-time digitizing." The little board allows for additional vertical offset correction to the CCD output depending upon the time/div. Without it, you will see a small but irritatingly noticeable vertical shift to the waveform as the time/div is changed in the ERD range. Apparently the original adjustments were not quite enough to cover the entire ERD range. I recall, from long ago, that some of the CCDs produced more voltage offset than others depending upon the clocking frequency; something to do with variations in transfer efficiency. Usually CCDs were clocked at a fixed rate and the offset is adjusted or cancelled by some external circuitry. ERD mode will operate the CCD at a rate unique determined by each time/div setting; hence, the extra offset adjustment. Anyway, that board is standard equipment on later units and not a custom trick for a special customer. I don't know what the other mod is that has four wires soldered to the CCD. If you are able to tell me which CCD pins, I might be able to find a clue. Clark |
DaveH52
Martin
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