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Re: Tektronix 453 Power Indicator Bulb needed
Sphere says they have 3 new in stock
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T1 Based Lamp 150-0045-00 Incandescent Lamp T-1 miniature lamp with base. New in factory bags. 3 New $5.00 On Mon, Jun 18, 2018 at 09:31 am, Michael Gladu wrote:
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Re: FS: Tektronix scopes on craigslist; North of Boston, MA
I picked up a 7844 from this seller last week. He's a nice guy and clearing
out a scope rehab hobby, apparently. -- Phil On Fri, Jun 15, 2018 at 1:26 AM Craig Sawyers <c.sawyers@...> wrote: $100 for a 067-0587-02 calibration plug in is a steal. |
Problematic Tek 7A26 Vertical Amp
I have a 7A26 vertical amp unit that is misbehaving. It is housed in a Tek 7704A. A borrowed (good) 7A26 operates correctly. The symptoms are as follows:
(1) The amplitude of a given signal does not remain constant when trace is scrolled from top to bottom on CRT. (2) Both channels behave as described here. (3) Occurs with low frequency traces (10 KHz) AND high frequency traces (10 MHz). (4) A signal that shows 3 div is positioned with the upper peaks at the topmost graticule line. (5) Its position is lowered using the POSITION pot to the next lowest graticule line and still shows 3 div. (6) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 2.6 div. (7) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 3 div. (8) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 3 div. (9) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 3 div. The rapid motion sequence of the positioning is that the trace size diminishes in the upper portion (at approximately the second graticule line down) briefly and then regains its amplitude. The pictures of this sequence can be seen at the following URL: Any suggestions on where to begin searching for this problem are greatly appreciated. -- William, k6whp "A friend told me to cheer up, things could be worse. So I cheered up and, sure enough, things got worse!" |
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Hi Menahem:
I should place the illinois capacitor link for comparison to the Nichicon . You'll see for the 50V, 2200uF cap I am using the KXM series (which I use mainly now) has much better ripple specs than Nichicon. --------------------Capacitor size is 18mm x 35.5mm----------------- illnois Capacitor: 3690 mA RMS ripple Nichicon PW: 3100 mA RMS ripple. |
Re: using scope channel 1 and channel 2 invert and add functions vs floating DUT
Thanks for the comment Steve ! I look forward to that document posting.
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Good point on the common mode resolution limitation. A question in regard to the CMRR, is the poor response a function of the scope speed and was it predictable? Would I be able to determine a max frequency just based on scope speed? NielsenTelecom On Thu, Jun 7, 2018 at 03:09 pm, ditter2 wrote:
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Tektronix 453 Power Indicator Bulb needed
Michael Gladu
I am looking for one B1107, 'Power On' indicator bulb, for the Tektronix 453 that I am trying to fix.
The Tek part number is 150-0045-00. Does anyone have one that they would like to sell me or can anybody suggest a place to buy a replacement? The bulb appears to be a custom built bulb and may be pure un-obtainium. :( Thanks. 73 de N1FBZ |
Re: 465 bad rise time
Im using a 50ohm cable a 50ohm through termination and a pg506 fast rise pulse.
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On Mon, Jun 18, 2018 at 08:31 am, HankC, Boston, WA1HOS wrote:
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Re: 465 bad rise time
What is the source of the signal being displayed ?
What kind of probe is being used ?Is it compensated ??Is the probe ground lead connected ? Do yourself a favor & lose the probe.Connect to a decent signal source, via coax, using a 50 ohm termination at the scope end. HankC, Boston |
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Jeff Davis
Hi Ron,
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I wonder if we may know each other. I knew a Ron who would be about your age who ran an engineering organization in Cedar Rapids. At the time, I was a brash young engineering group manager in a different organization who thought he knew it all. Life has a way of humbling one. Now I live in Southern California and fix up Tak scopes for fun and occasionally resell them. Still working, but probably not too much longer. Regards, Jeff You may address me as Ron, or Mac (for machineguy). I usually use Mac on the net and Ron in the "real world". >As a brief introduction, I am 78 years old, retired electronics engineer, now hobbyist, living in Iowa, USA. |
Re: 465 bad rise time
They share the same output amplifier.
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Re: Self Governance of TekScopes.
In the end, it is the moderator's responsibility to determine how he or she wished to have the list moderated. I this case, Dennis has laid out how he wishes the list to be moderated.
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DaveD On 6/18/2018 5:52 AM, JJ wrote:
I would think that it's the moderator's responsibility and no one else |
Re: 465 bad rise time
On Mon, Jun 18, 2018 at 04:41 am, Raymond Domp Frank wrote:
Yes I'm using the correct output. The rise time reminded me of my 7a26 that had bad var capacitors, but that only affected one channel. Seeing that are both channels are essentially the same just seems weird to me. |
Re: 465 bad rise time
You have the proper fast rise generator to perform an adjustment. The risk in my opinion is that you destroy a stuck trimcap or trimpot.
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You might first verify DC levels in the output amplifier stages and perhaps symmetry in the push-pull signals. Often some stages are common-base current driven which makes it more difficult to check signals. Unlike some other manuals the 465 manuals do not tell which part of the curve is affected by each adjustment. Which version output amplifier is in your 465, discrete or IC? It seems you use the pre-B250000 manual because of what you said about the 10X magnifier. The B250000-up manual clearly mentions the 10X mag. That manual also shows both versions output amplifier. On Mon, Jun 18, 2018 at 04:23 am, lop pol wrote:
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Re: Self Governance of TekScopes.
I would think that it's the moderator's responsibility and no one else
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(elders or otherwise) to filter the various threads. There are certain topics that are completely off topic like politics and should be cutoff. But, there are others that are technical and very informative which are gleaned from years of experience that allow us to pick up information that is very helpful. I welcome those. So, you need to have a jeweler's eye! John Justin On Mon, Jun 18, 2018 at 1:17 AM, Jeff Urban <JURB6006@...> wrote:
Bit odd you bring this up now when I just got through posting in a thread |
Re: 465 bad rise time
On Mon, Jun 18, 2018 at 04:23 am, lop pol wrote:
Before you start turning screws: 1. It is not uncommon for the variable caps to become open. I've had that happen to some in the vertical (output) amplifier. I've seen both the rotor not moving *and* the connection to the stator opening up. When screwing, check those first by watching their influence. 2. Look at the flatness of the square wave at lower frequencies (1 kHz, 10 kHz and up). I've seen an increase of the impedance in the differential circuits out of the delay line causing huge distortions, not just slow edges, by high-drifting low-value R's. Now that I've become involved, I have to ask a stupid(?) question: You *are* using the right i.e. fast edges of the PG506, are you? The left-hand BNC has a fast *fall* time, the middle BNC has a fast *rise* time. Raymond |
Re: 465 bad rise time
The BW limit switch is off. Turning it on increases the rise time and smoothed the trace like I would expect.Is the bandwidth limit turned on ( maybe a fault with the switching? ) verify the setup.Do you have any other scope with a higher bandwidth available? Some way to Yes but i checked the setup with my 468 (100 mhz) and the rise time was the correct 3.5ns On Mon, Jun 18, 2018 at 12:34 am, Albert Otten wrote: Ok. I will start turning screws. I just wanted to get opinions on whether this could possibly be a problem with a bad component prior to messing with the calibration. I would hate to have a bad transistor or capacitor causing the bad rise time and start turning the adjustments and mess up something that was actually already set correctly. .So BW = 0.35/risetime in seconds or 0.35/0.000000006 = ~~60 MHz.
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