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Re: 7633 for sale -- variable persistence scope
Hi
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Your problem is that in the UK where prices are higher than in the US at amateur radio rallies a 7633 with two or three plugins sell for under $50 73 George G6HIG On Friday, April 19, 2019 2:22 PM, John Griessen <john@...> wrote:
On 4/18/19 8:59 PM, John Griessen wrote: Needs help.? ?No response.? Ah well, high shipping prices mean disassembly for this poor tired broken scope. |
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Re: 7633 for sale -- variable persistence scope
John Griessen
On 4/18/19 8:59 PM, John Griessen wrote:
Needs help.No response. Ah well, high shipping prices mean disassembly for this poor tired broken scope. |
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Re: Scope-Mobile Cart Model 3 Disassemble
I recently bought one of these and I was able to get it into the back of a VW Golf cabriolet, even with the soft-top up. Indeed, the ability to open the roof of the soft-top was an advantage in getting the thing in! The main tilting shelf was adjusted to horizontal and the cart went in with its rear on the two rear seats, such that its narrow dimension was fore-and-aft in the back seats.
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Be aware that all Model 3 carts are not the same. Some don't have the framework and lower shelf, some have one lower shelf and some have two lower shelves. The bits and pieces that screw onto these lower shelves for the mounting of other scopes or TM500-series stuff are handy, too. If you get any of the mounting-straps, consider yourself lucky. Best of luck, Colin. -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of edwardhyliu@... Sent: 18 April 2019 16:07 To: [email protected] Subject: [TekScopes] Scope-Mobile Cart Model 3 Disassemble I am looking at purchasing one but its located about a hour away and I have a smaller car so I likely wont be able to transport it in one piece. Can someone advise on the tools I should bring with me in order to disassemble it down to someone that is easier to transport? |
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Re: P6201 FET Probe, 10X divider compensation question
On Thu, Apr 18, 2019 at 10:00 PM, Raymond Domp Frank wrote:
Thanks for the explanation and correcting my flawed assumption. I was aware that it is very sensitive, so I've been extra careful and will continue to me. It's a great tool to have. I've noticed it is highly sensitive to RF. I have an experiment on my bench with a 100 MHz clock coming out of an FPGA into my logic analyzer for state analysis and the P6201 is picking up the 100 MHz signal on top of the calibrator signal of the 2465B. Sean |
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Re: P6201 FET Probe, 10X divider compensation question
On Fri, Apr 19, 2019 at 02:10 AM, @0culus wrote:
Hi Sean, Glad that's solved. You have to realize that the compensation C of Hi-Z passive probes compensates for the cable and termination C at the 'scope that the probe tip "sees". The circuit in the head of the FET probe effectively isolates the (low-impedance) cable from the tip. Have fun with your P6201 and don't forget it is vulnerable to damage from static and higher input voltages, see the manual. Only use it without attenuator when necessary. Raymond |
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Re: Scope-Mobile Cart Model 3 Disassemble
Take a few pictures too, it will help.
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Leon Robinson ?? K5JLR Political Correctness is a Political Disease. Politicians and Diapers should be changed often and for the same reasons. On Thursday, April 18, 2019, 9:36:15 PM CDT, Paul Amaranth <paul@...> wrote:
And take some plastic bags and label the screws and bolts as you take them off.? It only takes a couple minutes and it will make reassembly trivial. ? Paul On Thu, Apr 18, 2019 at 05:04:01PM -0700, Dennis Tillman W7PF wrote: Hi Edward,-- Paul Amaranth, GCIH? ? ? ? ? ? | Manchester MI, USA? ? ? ? ? ? ? Aurora Group of Michigan, LLC? |? Security, Systems & Software paul@...? ? ? ? ? ? ? |? Unix & Windows |
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Re: Scope-Mobile Cart Model 3 Disassemble
And take some plastic bags and label the screws and bolts as you take them
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off. It only takes a couple minutes and it will make reassembly trivial. Paul On Thu, Apr 18, 2019 at 05:04:01PM -0700, Dennis Tillman W7PF wrote:
Hi Edward, --
Paul Amaranth, GCIH | Manchester MI, USA Aurora Group of Michigan, LLC | Security, Systems & Software paul@... | Unix & Windows |
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Re: P6201 FET Probe, 10X divider compensation question
Raymond,
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Thanks for your reply! I set up the scope and the FET probe as you said, and compensated it at 2 us. The adjustment was a bit fiddly so I followed the manual instructions for removing the tiny PCB inside the attenuator and cleaned + exercised the trimmer, which seems to have settled that down. Now it compensates much better! Thank you!! Sean On Thu, Apr 18, 2019 at 05:57 PM, Raymond Domp Frank wrote:
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7633 for sale -- variable persistence scope
John Griessen
It's got problems, but the CRT is good:
Shows a line at 2nd from top graticule line orig. from the left vert plugin norm triggering on line input, input O.C., and this line moves around vertically and horizontally, shows what you see when in non-store mode -- a storage blob that erase button won't clear. Needs help. At least it's nice and bright! Probably no HV trouble, just LV debugging to do... $80 shipped w/o plugins |
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Tekmate 2402 rebuild and programming
I recently got a Tekmate 2402 mainly because I thought it is cool and I like that it can piggyback to the 2440 scope I have. When I got it, it did not work. No hard disk, as expected. Both floppy drives non-functional. The battery in the NVRAM on the 286 MOBO was dead. I re-powered the NVRAM and replaced the FDDs. It worked well. It had no video, so I got a PC-104 VGA card.
The 286 mobo was designed as before there was a full standard for PC-104, nor for the mobo that also became a standard size. I decided to replace the mother board with something faster. The Versalogic VSBC2 (using a "586" CPU) fits. It appears that it was designed to be a mostly drop-in replacement for the AMPRO LB/286 in the 2402. One issue is that it DOES have standard layout for the PC104 header which is a mirror image of the LB/286 connector. Before I got the 2402, I was intrigued as to how the ISA bus header was connected. Was it a standard part, or was it a custom one for the 2402? Well, it is custom.... And it had a connector suitable for the mirror image PC-104 connector of the original LB/286 mobo. So, I had to make a PCB to convert the connector from standard to mirror image. Not a big problem. Also, the LB/286 is powered BY the ISA bus header through the PC-104 connector (not the other way around as would be expected). I maintained the power connections, and it CAN power the VSBC2 board. But I doubt the VSBC2 is designed to be powered properly this way. and I am sure the VSBC2 draws more power than the LB/286. So I modified the power cable to one of the floppies (also coming off the ISA header) to also power the mobo. It works quite well. Then I undertook the project for which I originally GOT the 2402 in the first place. I wanted to be able to store graphics images of the captures shown on the scope. I had hopes that the DSP-APP software for the 2402 would do that for me. But it does not. Also, I had hoped that the source code for the DSO-APP would be available. But I never found it. So I looked at some examples of C programming for the scope and wrote a very nicely functional program that interfaces to the scope in a similar manner to the DSO-APP software and will write SVG graphics files to the hard disk (yes, I added a flash-based hard disk), or to one of the floppies (selectable from the scope screen). It writes SVG type files. This file type is rather generic, so lots of software can read and display/print it. For instance Internet Explorer can do so. I had hoped to write the program to save it in PDF format so it would be even easier to print using the easily available Acrobat Reader. But that has not been achieved yet. It was quick for me to write the SVG part of the code because I had already written it for use on a microcontroller (e.g. arduino) for interfacting to the scope and saving to an SD card. If anyone is interested in my project feel free to contact me here on this group. -Tony |
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Re: P6201 FET Probe, 10X divider compensation question
Hi Sean,
There's nothing wrong with your P6201.Two recommendations: 1. Put the 2465B input at 1 MOhm DC or 50 Ohm DC, *not AC*. Use the P6201's External Terminator setting if the latter and in both cases use the probe's setting to select AC or DC coupling. 2. Compensate the P6201 at either 20us, 2 us or 100 ns / div, *not 1 ms* / div Raymond |
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P6201 FET Probe, 10X divider compensation question
Hi all,
So a while back I had the good fortune to find a brand-new, never used P6201 probe and accessories. The probe by itself is of course rated to 900 MHz, 100 Kohm, 3 pF. It comes with a slip on 10x 1 Mohm, 1.5 pF divider as well as a slip on 100x 1 Mohm, 1.5 pF divider. Both the dividers have standard screws for compensation. The scope I am using the probe with is a 2465B. The P6201 is powered from an external 1101 power supply and is set for internal 50 ohm termination, AC coupled, DC offset off. The calibrator signal is 5 Hz-5MHz and it says to compensate probe at 1 ms/div horizontal. The 100x divider seems to compensate nicely, however the 10x divider won't (seemingly). The photos in this album I uploaded (/g/TekScopes/album?id=89686) show what happens from 1 ms/div, 20 us/div, 2 us/div, and 100 ns/div. It seems to get after a certain point as I speed up the scope. Before I go and blame the 10x divider for being bad, I'm thinking that I might be fundamentally misunderstanding how to compensate when using an active probe? I read the P6201 manual and it only mentions the compensation screws in the dividers. Doesn't say anything special about using them, so I assumed that it should work just like compensating a passive 10x probe. However, since it looks better at fast horizontal settings, I'm thinking this might just be how this probe behaves at low frequency (relative to it's own passband)? I hope this is a PEBKAC (problem exists between keyboard and chair) problem rather than an issue with this probe... Thanks, Sean |
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Re: Scope-Mobile Cart Model 3 Disassemble
Hi Edward,
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John has the right idea. I just think you can never have enough tools with you. Along those lines I would modify John's list slightly as follows: Open end wrench SET (inch) Socket Wrench SET (inch) For me personally, I never go anywhere without a hammer and a vise-grips. A small can of penetrating oil might come in handy if there are any rusted bolts. If I remember correctly (it was over 15 years ago when I last took one of these apart) there are two VERY UNUSUAL screws that the top shelf pivots on. Those have to be removed with care. A few minutes familiarizing yourself with the mechanical drawing for the scope cart would be a good use of your time. If all goes well you should be done in 30 minutes. Dennis Tillman W7PF . -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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Re: Scope-Mobile Cart Model 3 Disassemble
John Griessen
On 4/18/19 10:06 AM, edwardhyliu@... wrote:
Can someone advise on the tools I should bring with me in order to disassemble it down to someone that is easier to transport?hex wrenches inch dimensions, open end wrench 7/16, 1/2, maybe others socket wrench 7/16, 1/2, maybe others posidrive screw driver #2 #3 ( or phillips) |
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Scope-Mobile Cart Model 3 Disassemble
I am looking at purchasing one but its located about a hour away and I have a smaller car so I likely wont be able to transport it in one piece. Can someone advise on the tools I should bring with me in order to disassemble it down to someone that is easier to transport?
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Re: Absurdly simple way to get contact cleaner into some Tek pots
Hi,
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You could search for "pot cleaning cap". They are commonly used for cleaning pots on guitars. There are variations on eBay. I have even seen people use threaded rod unions for the same thing. On 18 April 2019 17:21:18 BST, "Greg Muir via Groups.Io" <big_sky_explorer@...> wrote:
Does anyone remember the day of TV repair (when TVs could be repaired) --
Sent from my Android device with K-9 Mail. Please excuse my brevity. |
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Re: Absurdly simple way to get contact cleaner into some Tek pots
Does anyone remember the day of TV repair (when TVs could be repaired) where General Cement (GC) I believe had a neat tool for cleaning & lubing pots from the front panel. It was sort of a hypodermic syringe on steroids in the form of a body containing a plunger with the end being a threaded tube that matched the threads on the panel pots. One simply put cleaner in the syringe, removed the knob from the pot shaft, threaded the syringe on the pot bushing and pushed the plunger. The cleaner/lubricant would flow in through the interface between the pot shaft and the bushing into the innards of the pot.
A neat idea but a little messy since you were pushing a bunch of liquid into the pot but it was very effective and quick. |
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Re: Absurdly simple way to get contact cleaner into some Tek pots
Back in 2001 I had a tender experience with my 475's modpots.
At that time I was a novice... If you promise not to laugh too much.. here is the link to the surgery log: They are still working today. Ciao. Emanuele. PS: pls note the tender pics taken with a Creative Lab webcam connected to the parallel port of my Pentium II PC, :=) |
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Re: 475A : excessive jitter on delayed sweep
Tektronix tended to have a square pad on circuit boards on the positive side for the capacitors... also square pad on banded end of diodes...
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Jim?n8qoh On ?Wednesday?, ?April? ?17?, ?2019? ?07?:?23?:?35? ?AM? ?EDT, Alberto I2PHD <i2phd@...> wrote:
On 2019-04-16 16:35, Alberto I2PHD wrote: There is a suspect tantalum capacitor, which I did not replace, namelyProblem fixed. I replaced that suspect capacitor with a 4.7uF, 100V electrolytic, and now the delay time after which the B sweep starts is rock stable... Now I have a suspect, which maybe somebody could confirm or deny... look at this photo of the replaced cap : Should the mark indicate the negative side of the cap, then it was soldered in reverse, with the marked side connected to +14V.... If instead it indicates the positive side, then no manufacturing errors....? I am not much familiar with the markings of the tantalum caps.... In any case, now my 475A is perfectly working, and this is what counts... :-) -- /*73 Alberto I2PHD* Keyboard not found : Press F1 to continue/ |
Raymond Domp Frank
Emanuele Girlando
Alberto I2PHD