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Re: Guernsey Island 2445
Bob Headrick
As it turns out, I have the Tektronix 2645A with serial number B010101. I picked it up at Surplus Gizmos for ~$150 and have probably spent that much more in caps, keeper battery and probes.
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Had I known at the time this was the first unit off the line I may have looked for a different one.... I have appreciated the posts by Chuck Harris on debugging these, plenty to learn here. - Bob Headrick W7OV
-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Chuck Harris Sent: Monday, January 27, 2020 3:40 PM To: TekScopes@groups.io Subject: Re: [TekScopes] Guernsey Island 2445 I am 100% certain that tek started normal production units in the solid state era with B010101. [snip]
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Re: TDS784C
Ragnar S
Hi all,
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There is some calibration data in the EEPROMs on the acquisition board, but also in the NVRAMs on the CPU board. I have been told that you should never swap acquisition boards between scopes without also moving the NVRAM contents. Also, there are indications that there is calibration data that not even the field service calibration data will update, that was written at the factory. You are right that the NVRAMs are also used for storing waveforms, settings and other stuff. If you care about your scope I would _absolutely_ recommend backing up your NVRAMs and your EEPROMs. There are some DOS programs build for National Instruments GPIB drivers, mainly tekfwtool and getcaldata, as well as the floppy based tools that John pointed out, tdsNvramFloppyTool, that also has a Java program that can verify the checksums of your dumps. Both ways of getting your EEPROMs and the NVRAMs are a bit fragile, so I would recommend using two separate methods, or at least do it twice, and check that there is no difference between the results. Sadly there always is a difference in the first bytes of the NVRAM dumps, because that is where there real time clock is mapped (in the DS1486). Since I had no National Instruments GPIB interface around (but an Agilent USB one), and no DOS machine (but linux and unix machines), I did the little work it took to make them compile clean on Linux, on a Raspberry Pi in my case, fixed some simple makefiles and made a collection of the tools. Another guy wanted to run them on a Mac, which was trivial to fix as well, so I added that too. You can find my collection here: https://github.com/ragges/tektools Best regards, Ragnar
On 28 Jan 2020, at 18:23, Stephen Hanselman <kc4sw.io@kc4sw.com> wrote:
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Re: 56 pins (TM500/5000 and 5000 series scope plug-ins) and 76 pins (7000 series scope plug-ins) connectors
John Griessen
On 1/28/20 5:29 PM, Ke-Fong Lin wrote:
my goal is not to sell kits.I have a design in pcb-rnd, which can maybe export to kicad, but pcb-rnd is a better FOSS ECAD tool for my style. No one has asked for the sources and one has asked for gerbers. By the way, John, your Taiwan source, how much does a connector cost?Last time I bought a hundred for TM500, it was $180 +45 +30 = $255/100. You can't buy just one. Wiring is a big consideration. Few people wanted to deal with soldering 50 wires each end of a cable. Dan Meeks' TM500 kit with IDC connectors of thin wire gauge sold out quickly. An expensive pcb that is a straight through one side of copper + connectors would sell much better than a wiring kit. Be very careful with TM500 -- my kit never sold to recover its costs. The 7K flex extender did recover its costs and more, but I think that market is saturated now after I sold 200 kits to 7 countries.
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Re: TEK514 needs new 5V4G tube
greenboxmaven
First, you need to do research on which one the AudioPhools go bonkers over! Then search for the one they reject. I have actually seen technicians and customers try a dozen different brands and types of 5V4s, trying to find the one that sounded best to them. I have seen them claim they can tell the difference between silicon rectifiers made by General Electric or Motorola. Some of the old metal 5V4s were of very unique construction. The envelope was a perforated metal screen. Inside were two metal cylinders- the plates, with seals at each end of the cylinders where the filament connections went in and out, and of course to seal the vacuum. So far, all of the Tektronix scopes I have seen will accept all three types. For testing, use a 5R4. They tend to be far more plentiful. They are probably not good to leave in the scope, they do have a higher forward drop than a 5V4 and are directly heated. On the other hand, they are far less likely to be fatally damaged if you have not yet found the short or cause of the overload. When working on any device using an indirectly heated rectifier, check the power switch, fuse holder, wiring, and any power connectors or cords for intermittent connections. A serious abuse of a 5V4 is to interrupt the power for a few seconds and then restore it if you have a condenser input filter. It is fully heated, the filter condenser is discharged, and the inrush current to recharge the condensers is brutal. If it is a choke input filter, there is usually no problem.
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Bruce Gentry, KA2IVY
On 1/28/20 12:56 PM, Chuck Harris wrote:
Back in the olden days, if you saw:
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Re: 56 pins (TM500/5000 and 5000 series scope plug-ins) and 76 pins (7000 series scope plug-ins) connectors
Ke-Fong Lin
Hi everyone,
I debug by removing the top cover of my TM503 or the left, right, and top sides of my TM5003. That gives almost as good access as the pictured "naked" TM502. But my problem with an FG507 plug-in is with the power supply. I'd like to use my bench supplies to send the +/-33V and debug it from here. The connector would allow me to do that without having to solder wires on leads of components on PCB. Regarding the extenders, my goal is not to sell kits. But rather to design an edge PCB car, put the Kicad sources and gerber files. So anybody can have one fabricated and buy the needed parts. By the way, John, your Taiwan source, how much does a connector cost? The EDAC ones are almost 17 euros! Best regards,
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Re: debugging TM500 modules
Hi Bob:
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Your excellent discovery that the TM502 power supply can be totally removed from the mainframe would haved save a lot of time years ago if I had only known about it. Many years ago I made a TM500 plugin test fixture by cutting off the front 80% of a TM501 unit. This required a metal chop saw and a lot of filing and other work to remove the rough edges. My solution is a kluge compared to yours. I'm embarrassed as I recall how much work it took to modify the TM501 when I see how simple your solution is. Yours solution also comes in handy when you need to test double wide plugins. Thanks for thinking outside the box. Dennis Tillman W7PF
-----Original Message-----
From: robeughaas@gmail.com Sent: Tuesday, January 28, 2020 2:01 PM To: TekScopes@groups.io Subject: Re: [TekScopes] debugging TM500 modules https://groups.io/g/TekScopes/album?id=239714 Photo of a "naked" TM502 as a service tool. -- Bob Haas -- Dennis Tillman W7PF TekScopes Moderator
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Re: debugging TM500 modules
Vince Vielhaber
That's a really good idea!
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Vince.
On 01/28/2020 05:00 PM, robeughaas@gmail.com wrote:
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Re: DC 503A part
Ed (SCSKITS)
Not having a board on hand I can not be sure of the LED dimensions, but the pinout is similar to the HDSP-7503 display from Broadcom.
ed
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Re: DC 503A part
Ed (SCSKITS)
You may be thinking of the board I made for the DC508 counter.
It could be modified (new board) to fit the DC503A, but I would need an original board for the pattern as there are no dimensions in the service manual. If it is just one LED display digit that is out it should not be too hard to remove, the same LED may have been used in other units. At least it looks like this board has connectors and is not hardwired as some of the older units. At least the displays used on this unit have the decimal point on the right side rather than on the left, so it may be possible to find a off the shelf replacement. ed
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Re: debugging TM500 modules
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Re: TDS784C
JJ
Steve,
Here is the link to the discussion on using Java SW to copy your NVRAM data using the TDS784C internal floppy: https://www.eevblog.com/forum/testgear/tektronix-tds500600700-nvram-floppy-dump-tool/ There is seller on eBay that sells those two chips (or the equivalent thereof) mounted with external coin cell batteries on top of the chip. He has gotten high ratings from other TDS scope owners on their quality. He states that he will program the chips with your backup data if you want. You still need to remove the chips yourself though - so you will need a good quality solder sucker like the Hakko. There are also YouTube videos showing how some pros removed the chips - you should look through them. Some TDS owners have said that just heating the chip pins caused the chips' batteries to drain - some claimed that apparently the chips' batteries were right on the edge.of failing. Best, John Justin
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Re: TDS784C
Siggi
On Tue, Jan 28, 2020 at 9:14 AM Steve Hendrix <SteveHx@hxengineering.com>
wrote: I'll probably think of it right after I hit "send", but what does SPCSPC stands for "Signal Path Compensation". This injects a calibration signal into the pre-amplifiers for each channel, and calibrates away any DC offset in the signal path (https://www.tek.com/support/faqs/what-spc).
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Re: TDS784C
victor.silva
Steve,
I don't know what you consider a low ball offer but I usually make brutally low offers on liquidator's equipment because usually it's so overpriced. I usually start at a max of 10%~20% of the asking price and go from there, unless of course I see a stellar deal that I'm sure will be snapped up very quickly. For example, I've seen liquidators list 2465Bs for $1000 and I'll offer $125 and they have accepted. Many liquidators have no idea of the value and they simply go on ebay and list their stuff for the highest price they can see. Good luck with your TDS784C. You may eventually need to convert to LCD because those shutter type LCD/CRTs will eventually fail. --Victor
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Re: debugging TM500 modules
I've seen late TM503's (nomenclated TM503A) with a self-contained power supply but all the TM504's I've seen don't have a removable power supply assembly. A "naked" TM504, even a TM503 would be cumbersome on the bench.
-- Bob Haas
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debugging TM500 modules
John Griessen
On 1/28/20 11:40 AM, robeughaas@gmail.com wrote:
I find a convenient way of debugging TM500 modules is to use a bare TM502 power supply. It can be removed from the case. Youcan rotate it to get convenient access to the plug-in. It can be use with double-wide plug-ins such as the SC504. How about using a TM504? Does the cover come off those easily?
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Re: 56 pins (TM500/5000 and 5000 series scope plug-ins) and 76 pins (7000 series scope plug-ins) connectors
John Griessen
I had some (7000 series scope plug-ins) connectors made, but am out of stock right now.
If you want to order 100, I have a source in Taiwan.
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Re: 56 pins (TM500/5000 and 5000 series scope plug-ins) and 76 pins (7000 series scope plug-ins) connectors
I find a convenient way of debugging TM500 modules is to use a bare TM502 power supply. It can be removed from the case. You can rotate it to get convenient access to the plug-in. It can be use with double-wide plug-ins such as the SC504. I'll attach a photo when I figure out how to do that.
-- Bob Haas
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Re: TEK514 needs new 5V4G tube
Chuck Harris
Back in the olden days, if you saw:
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5V4, you were talking of the metal envelope tube. 5V4G, you were talking of the coke bottle glass tube. 5V4GT, you were talking of the straight sided glass tube. Metal tubes largely fell by the wayside, as they were expensive to make, and caused problems with capacitance... 5V4GA, is typically an outlier, as it should be marked as 5V4GTA, but the "T" envelope was standard by the time any of the letter revisions came out, so the nomenclature revised it to simply "GA". -Chuck Harris Steve Hendrix wrote:
At 2020-01-28 12:11 PM, Tom Phillips wrote:Thank you for that clarification. I was puzzled by the fact that two adjacent 5V4G tubes were in different bottles. So if I'm reading your comment correctly, the straight-sided, smaller one is newer (possibly replaced at some past time) and the bad one in the larger "coke bottle" glass is older, possibly the original.
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Re: Guernsey Island 2445
Chuck Harris
Colin,
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Hatchet is sheathed. My point on my spelling of Guernsey, is the only internal spelling checker I have in me (an intentional redundant redundancy) spells phonetically. So, every time I type Guernsey, I start out "Gurn" before my higher brain function catches my mistake, and causes me to back space 3 times, because twice wouldn't do, would it? And then I type "G...u..ernsey". This happens every blooming time! If my higher brain function is distracted by doing other higher brain things, the correction doesn't happen. Each and everyone of us (who isn't a liar), has a problem like this that vexes them. For some it is spelling, for others it is homonyms, and others, its it's (snort!), or who vs that, or effect vs affect, or colors we see differently from others, ... it is always something. If it doesn't really affect the point being made, I try to just let it go. You say colour, I say color... we are all different. -Chuck Harris Colin Herbert via Groups.Io wrote:
Chuck,
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Re: TEK514 needs new 5V4G tube
Steve Hendrix
At 2020-01-28 12:11 PM, Tom Phillips wrote:
Thank you for that clarification. I was puzzled by the fact that two adjacent 5V4G tubes were in different bottles. So if I'm reading your comment correctly, the straight-sided, smaller one is newer (possibly replaced at some past time) and the bad one in the larger "coke bottle" glass is older, possibly the original. Also thanks for the tips on a good source. Steve Hendrix
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