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Re: Pallet of scopes for sale
Thank you; I thought so, someone else didn't. I finally have some older
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equipment to work on as a hobby this winter. I would have loved to have had a 500 series scope (other than curve tracer), but it will still be similar to relive my earlier life - lol. The first scope I ever used was one of those 500 series (I don't remember which one). I can remember in Electronics school there was this older gentleman who maintained all those old scopes. Being arse-holes like we kids were, with those 500 series scopes the graticules, if I recollect correctly, were on the blue external screen. We learned that if you put tracing paper under that blue screen, they didn't focus worth a darn. So the lab teacher would be called over, he would look and then just give a new scope and that one would head to the old man. A few hours later, we heard this "OH GOD Dxxx!" coming from his lab. The lab teacher would break down laughing (knowing what we did). I really don't think those things could fail on their own, at least in 1979/1980. Internally, they are electronic art. Gorgeous! I later ended up getting one from the military surplus, but after my job, early in life, took me to Cincinnati and had everyday filled, I really don't remember what happened to it. I think I sold or traded it at a hamfest, I really don't remember as that was 35-38 years ago. So with the 575, I can re-live a little of my youth, which I pine for. How can you put a price on that? On Wed, Jul 8, 2020 at 3:20 PM Chuck Harris <cfharris@...> wrote:
Lose money??? for what you got, that was cheap. |
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Re: 1240 / 1241 Logic Analyzer Lithium Battery Removal
Chuck Harris
Hi Andre,
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I am probably your original source for the story about how the Catalyst Research Corp lithium battery made a mess of my 1240. It totaled the multilayer CPU board, so I had to replace it too. The same, or a similar cell is used in the RAM cartridges, so they should be serviced as well. I replaced mine with a socket, and lithium coin cell that was the biggest I could find. I should check it out to see if it is still holding memory, as it has been a while since I made the swap. The only thing the cell protects is the setup, so it is safe to pull the board, and simply replace it. I wouldn't go out of my way to short circuit the cell, but I wouldn't worry too much about doing so, either. -Chuck Harris Andre D'Amours via groups.io wrote: Hello Everyone, |
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Re: Pallet of scopes for sale
Chuck Harris
Lose money??? for what you got, that was cheap.
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You got a very good deal. -Chuck Harris David Kuhn wrote: " While not out of line for a 576 + 2 575s plus misc other stuff it |
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Re: Pallet of scopes for sale
" While not out of line for a 576 + 2 575s plus misc other stuff it
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was not what I would consider a bargain." I'm the idiot that won the auction. I had a nice vacation out of getting the equipment and visited the two largest flea markets in the Cincinnati area, when I was out there over this last weekend. The was TWO (575s) on the pallot (I thought only one) in addition to the 576. There was a worthless HP Logic Analyser. There was however a nice HP 10K-1.5GHZ Spectrum analyzer and it appears to work and has a great CRT. Also on the pallot, all those 576 plugin, three TDS420A (I think) with GPIB ports and Thermal Printers and scope probes. The one I tested in the hotel room seems noisy on the test square wave probe calibrator, but had a really good and bright trace trace. It also seemed to go to some ridiculously high digitation rate for a scope like that. The thermal printer worked. There also were two no-name brand analog scopes and a Tek 2245 Analog scope that works fine and has a great trace. There is more stuff in the boxes too. Seemed like foam with a bunch of transistors in it with the gain documented and a few other things. I am not sure what I am going to do with all that stuff. For now, it is getting unloaded into my one shed. Next month, a friend will help clear out the garage and the industrial shelves and move all the gear to there. I don't really have a use for it, but if it works, the 576 will sit in the corner of my large bench and look impressive (if I keep it). I don't know because of their weight, if I will try to sell the 575's or part them out. Having them packed and then shipped would probably cost $50 for professional packing and another $100+ shipping, which no one will want to pay. So confirming that they work and then parting them out, may be the best option, but not until I play with them for nostalgia's sake. When I went to Electronic School in 79-81, they had them and they were old back then. So I want to admire them inside and out and then figure out what to do with them. The other scopes should be okay for sale if I want. Heck I think I paid $400 for NOS for a GPIB interface for a TDS420A that I already had two/three years ago. I really don't care if I lose money on these units. We had a blast back home over the weekend and the excitement of searching through all the stuff on the pallot. Plus at the flea markets (with masks of course), my kid got a couple of DS Games and a sword. Then at Microcenter Mall in Cincinnati, my kid also picked up a professional microphone and accessories for his future "game podcasting career" (heh heh heh) and we got a 3D printer to play with for my wife's crafting. All, in all, it was a good 4 days. Not a bargain or not, I am happy. Dave On Sat, Jun 27, 2020 at 4:08 PM Paul Amaranth <paul@...> wrote:
For those who are interested, the bid closed at $655 + $50.44 buyers |
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Re: Purpose of Q32 in S-52
Thanks for the replies so far. The common thread is protection of the TD in case of other failures. I was thinking along the same lines, but also thought that one single other failure could do no harm, except perhaps a way too high +15V.
For instance a missing -12.2V would shut down U10 and U20, having the same effect as states 1 and 10-16 in normal operation. Then the TD current supply via R97+R98 would permanently be present while the TD is in the low state. That alone would do no harm I think. I was also thinking of an interrupted R109 and hence missing -5.1V, -3V and -2.5V. That would have more or less the same effect as a missing -12.2V. In case the zener VR109 dies (to open circuit) U10 and U20 will be destroyed but Q32 doesn't mind. Albert |
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Re: Tektronix 2465b Boo Boo
Chuck Harris
I am of the general opinion that the only reason to buy
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a "pre-calibrated" DS1225, is because you are selling your scope, and you want to fool the potential buyers into thinking the scope is calibrated. Kind of the tektronix version of turning back the odometer on a used car. I hope he wasn't thinking a pre-calibrated NVRAM is a legitimate solution to any real problem. -Chuck Harris satbeginner wrote: Putting in a pre-loaded Dallas or Fram will remove the 'not calibrated' indication (?????? or ............), but this will mean the scope from now on is |
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Re: Digilog
Chuck Harris
I may be wrong, and Roy can certainly fend for himself,
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but he is agreeing with you. The puzzling results he mentions are the ones you get when your dead certainty that there are only ones, and zeros, and nothing in between. Runs into something in between. -Chuck Harris Dave Daniel wrote: Hmmm.... I don¡¯t mean to be argumentative, but, outside of text books and digital simulators ( e.g., Synopsy VCS, Modelsim, etc.), what real-world circuit is not analog?On Jul 8, 2020, at 09:51, Roy Thistle <roy.thistle@...> wrote:On Wed, Jul 8, 2020 at 05:18 AM, Dave Daniel wrote:Probably not necessarily. But, I agree: we tend to want to believe the world is the way we perceive it... and that bias sometimes leads to particularly puzzling results. |
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Re: Tektronix 2465b Boo Boo
Putting in a pre-loaded Dallas or Fram will remove the 'not calibrated' indication (?????? or ............), but this will mean the scope from now on is
"Not Calibrated", only it will not be visible to a user. The error could be anything from 1% to 15 or more %, depending on the parameter used. Timebase, Amplitude, Delay, etc. Putting in a pre-loaded replacement is the ostrich way.... The only real way to go is calibration. Just my 2cts... Leo |
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Re: Tektronix 2465b Boo Boo
On Wed, Jul 8, 2020 at 07:00 PM, Chuck Harris wrote:
I'm under the impression that the OP thought he'd solve his problem by replacing the NVRAM with a nice, clean one. You're right that he came up with the idea but our reactions didn't make it clear that unless he buys one of those preloaded NVRAMs containing "some general" calibration data, he won't solve his problem that way. BTW, I'm not a believer in the preloaded NVRAMs but of course, I'm biased because I have the equipment and I have calibrated these 'scopes - and I have replaced NVRAMs, both with new ones and with FRAMs. "Preloaded" calibration data may be good enough for some/many, don't know. I'd guess calibration may be 2 - 5% off, right? Raymond |
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Re: Tektronix 2465b Boo Boo
Chuck Harris
The NVRAM swap was the idea of the original poster... not any
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of us. The only advice given was Exercise 3 by Tom, and an explanation of how the problem occurs by me. After he asked what NVRAM to use, I told him, and warned about trying to remove the old NVRAM using substandard means. Some of the calibration steps will not allow you to step through them without making changes... for example: the vertical calibration, the trigger calibration, the parametric calibration, all do their thing automagically using the specified voltage coming from your voltage calibrator. If the voltage calibrator is not there, the routine will fault with a bunch of dots, and if you quit early, a bunch of question marks. I wish there were a way of aborting without making changes, but tek didn't do that. Why do I wish that? On more than a few occasions, I have finished a routine, and with my head running on autopilot, re-entered the just finished calibration step, requiring me to do it all over again, or suffer the ???? display. -Chuck Harris Raymond Domp Frank wrote: Please forgive me for asking but I can't quite follow. |
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Re: Digilog
Hmmm.... I don¡¯t mean to be argumentative, but, outside of text books and digital simulators ( e.g., Synopsy VCS, Modelsim, etc.), what real-world circuit is not analog?
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On Jul 8, 2020, at 09:51, Roy Thistle <roy.thistle@...> wrote:On Wed, Jul 8, 2020 at 05:18 AM, Dave Daniel wrote:Probably not necessarily. But, I agree: we tend to want to believe the world is the way we perceive it... and that bias sometimes leads to particularly puzzling results. |
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Re: Tektronix 2465b Boo Boo
Please forgive me for asking but I can't quite follow.
The OP told us that his 'scope was working fine but that he hadn't been able to resist the temptation to enable "cal" mode and play around. That resulted in the bottom line with lots of question marks. As far as we know - or hope, the 'scope is still about as much in calibration as before. He also told us that doing a cal. is no option for him, technologically nor financially. Where does the advice come from to replace the NVRAM, except for the fact that it may lose its memory soon? It may not for a while if left untouched. If it does during replacement (that has happened before), he won't be able to recover. Why not just advise the OP to follow Chuck's advice to step through the procedure he started but didn't finish or first do an exercise 3 and hope for the best? When restarting - and finishing the procedure the OP started, he should finish it all the way *without* changing anything, if possible. After performing his steps, the OP should switch off, then on. Raymond |
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Re: Tektronix 2465b Boo Boo
At the risk of contradicting the master of the 2465 scopes -Obi Wan Harris- when I removed my NVRAM chip I used a simple soldapullt solder sucker (albeit one of the good quality ones - EDSYN) and in the end the chip just fell off the board by itself after the last pin was cleared. Even the ground pin was cleared quite easily without using anywhere near excessive heat. Just make sure to first "wet" each joint well with fresh good quality solder (for me that would be Kester 44), and that will make it much easier for the thru holes to be cleared on the first try. So even tough I would agree that a desoldering station is probably the best way to do this job, or at least the one with the least risk to the board, if you are in the middle of nowhere don't be afraid to use simpler methods as long as you are comfortable with it and have the proper expertise in using the desoldering tool of your choice. And be patient, don't rush things making sure every single pin is clear and confirmed loose before you start pulling on the chip. Sometimes the pin can still be slightly stuck even tough the hole looks clear, then you can try wiggling the pin a bit towards the center of the hole and most times it will just break free. Otherwise refill the hole with some more fresh solder and try again. Hope that helps.
BTW get your replacement NVRAM from a reputable place like Mouser (or Digikey), never from Ebay, specially avoid if it comes from Chinaland, as it might be an old relabeled chip with an internal battery that is well past its expiration date. Also get a good quality low profile socket to reinstall the new chip. I got mine from Mouser, one of the machined pin type, although some people say its best not to use this type but rather the convention kind. In any case it worked for me. Good luck with the repair, and please report back your progress. |
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Re: Tektronix 2465b Boo Boo
Chuck Harris
There is really only one issue with the 1225 you use,
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and that is it must be the sort that trips at the right voltage. The speed is of no consequence for such a slow microprocessor. Dallas as a company doesn't exist anymore. Maxim bought them. I use DS1225AD-200IND+'s. I didn't know the "Y" was still available. It wasn't for a while. Whatever method you use to remove the part, keep the temperature down. I do not recommend using solder wick, as the pins have to get way too hot, and the wick never gets all of the solder, leading to tearing out plated-thru holes. A desoldering station is essential, in my opinion. Also, there are traces right tight against the solder pads. It is very easy to break one of them if you get too aggressive. -Chuck Harris squirrel@... wrote: Thank for that Chuck I live in Australia in a small country town I have no access to the required equipment to do a full cal I did ring a company in the city and the kick off price for a full cal was $1200.00 not to mention the exuberant freight cost this is way more than the scope is worth. |
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Digilog
(Responding to Ed Breya¡¯s explanation of the term ¡°digilog¡± woth a new thread)
Thanks. I¡¯ve never heard the term before. Indeed, everything is analog and ignoring that fact when dealing with ¡°digital¡± signals can lead to misunderstanding of how things work. When I worked with Sun T8 servers witk clock rates in excess of 4 GHz (they never got to the 4.5 GHz target), there was no digital anything about them except in the grossest abstractions. DaveD |
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Re: R7704+7A18+7B53A in Newport Beach, CA to part with
Hi ABC XYZ (what's your real name?),
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please contact me offline for details. Thanks! Chris On Tue, Jul 7, 2020 at 10:12 PM, Abc Xyz wrote:
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Re: Tektronix 2465b Boo Boo
Thank for that Chuck I live in Australia in a small country town I have no access to the required equipment to do a full cal I did ring a company in the city and the kick off price for a full cal was $1200.00 not to mention the exuberant freight cost this is way more than the scope is worth.
However I am retired and a hobbyist only so close enough is good enough for me. I'm about to order a DS1225Y from Digikey I see there are 4 different ones 2 available "DS-1225Y-150+-ND" DS-1225Y-200+-ND" which one should I get the 150 or 200 I also notice these are Maxim chips. I have a Willem 4.1 burner which list the DS1225Y . Cheers |
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Re: Purpose of Q32 in S-52
On 08/07/20 02:11, Ed Breya via groups.io wrote:
"Digilog" is just a term I coined decades ago, referring to circuits that are both digital and analog, sometimes without clear distinction. In reality, everything is analog, including digital circuits, until you go deep enough, then it becomes kind of digital (discrete) at the quantum level.Yes. In digital circuits analogue waveforms are interpreted by the receiver to infer digital signals. Assuring that the interpretation is clear and unambiguous is termed checking the signal integrity. But before you get to the quantum level, there are two classes of circuit that are in some senses digital: single photon avalanche detector circuits, and femtoamp? circuits. |
satbeginner
Raymond Domp Frank
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