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Re: On screen display and other CRT items....
Dear Don,
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I assumed that 40 k to 80 k applied to scope CRTs, not raster driven. Somehow, and possibly wrongly, I assume that scope CRT is made more durable than raster one, if for no other reason then for size and price expectations. The scope CRT does have more glass penetration points (a draw back), but glass envelope can be made thicker considering the size of the whole device. I plucked 10 k number from life of 'Long Life Tubes', you know, E800F as opposed to standard EF800, though somewhat longer life would be expected when you shell out few thousand bucks for a tube. It surprised me when Walter said that he found lot of 'gassy' tubes. I always associated that with TV CRTs (I view TV as something at par with PC in cheapness). Walter, was gassing perhaps coming from pin abuse (bent pins close to glass)? The PC monitors should not be brought into this comparison; in olden days they were the cheapest thing that could be found and I do not think that much has changed. To give you an idea about attitudes in PC industry (and some laughs or concerns perhaps), let me digress. Few years ago I went to a seminar on switch mode power supplies, given by Linear Technology. Apparently, switch mode ICs are competitive commodity and Linear Tech is trying to sell theirs as a 'cut above'. Their head application guy, Jim Williams, usually says: 'before we had switch mode ICs we were telling customers not to use switch mode power supplies (SMPS) because of noise and now we say that is the only thing'. During lunch I set at the table with one of SMPS application guys and he was telling about trip to Taiwan. They were at a mother board supplier (name withheld) and Linear Tech guy pointed that with low value inductor (hence cheap) ripple current was killing electrolytics. Taiwanese guy asked 'what is the problem when warranty on product is 30 days'. In contrast to junky PCs, I had a VT220 terminal for 10 years. Intensity was turned up as high as it would go, to be able to read screen in office light. The monitor was opened up ones to increase maximum intensity limit and it still lives; the terminal operated in 24/7 regime. It is true that VT220 shuts down CRT after no key strokes or input data for ??? an hour. But, company also had a half a dozen of monitors hung on test systems, which were getting periodic input from computer at intervals from 15 minutes to couple of hours, so they were driven hard. I do not think that any CRT failed, though there were few failures. I did not let terminals be repaired (I could buy replacement for under $50), but few, that technicians sneaked by, never turned up bad CRT. Funny that you mention high intensity in auto sweep mode. It looks like all test technicians love that; and they are usually young, with good eyes. The furthest that I got with that problem was that technicians would sometime turn down brightness when I walk into test department. At place where I worked, I know that technicians did not understand concept of synchronizing signal and probably upped brightness to be able to see something in trace as it flies by. Their use of scope has always been a mystery to me: how do you know what you are looking at with only one probe and no external trigger? What is 571? I could not find it in Stan's book, neither in 1995 Tucker catalog. Regards Miroslav Pokorni ----- Original Message -----
From: <donlcramer@...> To: <TekScopes@...> Sent: Tuesday, January 22, 2002 11:22 PM Subject: Re: [TekScopes] On screen display and other CRT items.... I was initially surprised by the 40-80Kh number also. The difference Ithink is that in a scope the tube is not driven as often (duty factor) or ashard (especially white background applications) as a CRT is in a raster scanto last a lot longer now than 10-15 years ago. Remember those old 12"series desktop computers)? If we left those greenscreens on 24/7 on our burn-inreplaced, the production operators would turn them down at night before they wenthome, and left them down whenever they did not have to see the display. Inlater years (the systems ran 17 years I'm proud to say), we couldn't even find"screen saver" pictures on them when not in use.through two shifts, 5+ days a week, in auto sweep mode (with the brightness turnedup too high to boot). To the best of my knowledge, we've never pulled a CRTin any of the scopes, and most of those go back more than 10 years (includinga couple Tek 465Bs, Leader 100Mhz dual trace, a couple Tek 2200 series).Any more we would junk them for whatever cause if they failed--I have two Igot that way. One (465B) I restored and the other (TAS465) I haven't found amoons ago) which exhibits the double peaking on the intensity control thatothers have mentioned. The trace is pretty dim when cold, though improves with arunning. Quite frankly, I don't think there is anyone left besides me that can runit anyway so it is in a way "out to pasture". I've wondered if a replacement |
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Updated WEB
JOSE V. GAVILA (EB5AGV/EC5AAU)
Hello!
I have updated my WEB pages to best show my test equipment illness...errr, collection ;-). Look at: Then click on the 'Latest additions' section over the 'Test Equipment Collection'. I plan to add lots more info and pictures, linked from that page. But I needed to start from somewhere, hi! Hope you enjoy it. Regards, JOSE ---------------------------------------------------------------------- 73 EB5AGV / EC5AAU - JOSE V. GAVILA La Canyada - Valencia (SPAIN) EB5AGV Vintage Radio Site: European Boatanchors List: |
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Re: Anybody need these Tek tubes?
Phil (VA3UX)
Hi Walter.
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I could probably use the 5642's and 12AU6's for my pile of 500 series scopes. The 8136's - not sure what they're for but I'll check my manuals to see if they're used in anything I have. Those old 555's and 556's have so damn many tubes in them that I can't remember the tube line-ups anymore. Thanks Phil Turcotte Grimsby, Ontario At 06:12 AM 1/23/2002 +0000, you wrote:
Recent comments about Tek matched tubes reminded me I had some |
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Re: I found a nice 7CT1N :-)!
JOSE V. GAVILA (EB5AGV/EC5AAU)
Hi Mark,
(I copy this to the List as think somebody else could be interested. Please, correct me if I am wrong!) The 7CT1N connector I was thinking of was a header with the threeWell, I don't want to earn money with this but produce something useful :-). I have access to double sided PCB sheets (copper on both sides), so it could be the basis to produce the PCBs. To support a perpendicular panel, I would use some kind of PCB header, with gripping action. Perhaps you can do a fast draw of your idea; if you want, we can share this at my WEB site and ask for further improvements. What do you think? Certainly CNC is the way to go. Just what I need... more tools :-)Well, I did not buy it for hobby purpose... but having it at my workbench really helps, hi! Regards, JOSE ---------------------------------------------------------------------- 73 EB5AGV / EC5AAU - JOSE V. GAVILA La Canyada - Valencia (SPAIN) EB5AGV Vintage Radio Site: European Boatanchors List: |
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Re: I found a nice 7CT1N :-)!
L. Mark Pilant
Hi Jose.
The 7CT1N connector I was thinking of was a header with the three banana plugs in the back (to plug into the 7CT1N) a flat bottom (perpendicular to the back) a sloping front with room for two sockets and the A/B switch, and a short front. If I was particularly ambitious, I'm make up several of the basic header assemblies and have the sloping panel be removable. I bet there would be a small market for these; but I don't know what the profit margins would be :-) Certainly CHC is the way to go. Just what I need... more tools :-) (I'm a tool addict a well as a test equipment addict :-) :-) 73 - Mark N1VQW |
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Re: I found a nice 7CT1N :-)!
JOSE V. GAVILA (EB5AGV/EC5AAU)
Hi Mark and all the List,
First, thanks a lot for the nice explanation; my unit will come with a photocopy of the user's and service manual. I hope it is of good quality... One of the things on my list of things to do is to build a selectionHere I can sure help :-)!. I own a CNC precission milling machine... One of my very next projects is to build an small PCB with the three banana jacks and a choice of transistor sockets or perhaps a header to connect there an adapter with two sockets and an A/B switch. What do you think?. I am sure we could end with an interesting design! Regards, JOSE ---------------------------------------------------------------------- 73 EB5AGV / EC5AAU - JOSE V. GAVILA La Canyada - Valencia (SPAIN) EB5AGV Vintage Radio Site: European Boatanchors List: |
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Re: I found a nice 7CT1N :-)!
L. Mark Pilant
Jose and Dick, I have a 7CT1N as well as a manual :-) so I may be
able to help. In a nutshell, the 7CT1N may be used in any (vertical or timebase) slot. There is a push button on the front panel which you use to indicate the slot in which it is being used. Since you need an amplifier plugin, using it in one of the timebase slots is the easiest. Then you simply pull the little white/cream colored cable out from the 7CT1n front panel and connect it to the vertical input channel of the plugin. If you use the 7CT1n in a vertical slot, you need to make sure you use a timebase plugin allowing external access to the amplifier section. (Such as the 7B50, 7B52, 7B53, and 7B70 plugins.) That should get all the basic connections done. From there, all the remaining controls should be pretty easy to figure out. BTW, I have mine in a 7704A with two 7A26 vertical plugins, the 7CT1N, and a 7B80 timebase. This allows me to use it as a regular (three channel :-) scope or a curve tracer. Although I don't use it much as a scope since I usually use my 7904. One of the things on my list of things to do is to build a selection of plugin connectors for the 7CT1N to make it a little easier to test devices. I'll also include an A/B switch and two sockets to also make comparisons easy. (I really like this feature on the Tek 575.) That's it for now. 73 - Mark N1VQW |
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Re: Who's up to some remote troubleshooting?
JOSE V. GAVILA (EB5AGV/EC5AAU)
Hi Lynn,
I have a service manual for the 7A26 and could scan any schematics part you need, if that helps. Regards, JOSE ---------------------------------------------------------------------- 73 EB5AGV / EC5AAU - JOSE V. GAVILA La Canyada - Valencia (SPAIN) EB5AGV Vintage Radio Site: European Boatanchors List: |
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Re: Who's up to some remote troubleshooting?
Lynn Lewis
Thanks, Stan. That's sound reasoning. I thought about it early on but having
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never pulled or installed a Tek IC, I was reluctant to mess around with the good 7A26. Now that I've done a few, I don't think it will be a problem. I have "anti-static finger cots" that should keep me from blowing a good IC. I will definitely try that. Lynn -----Original Message-----
From: Stan or Patricia Griffiths [mailto:w7ni@...] Sent: Tuesday, January 22, 2002 11:59 PM To: TekScopes@... Subject: Re: [TekScopes] Who's up to some remote troubleshooting? Hi Lynn, I'll be the first to admit I don't know much about troubleshooting stuff with IC's in it but here is what I would do, if it were mine, and I had the stuff that you have. It sure sounds like U2750 to me . . . and to you too, because you have replaced it twice with no luck. To be certain it is not U2750, I would like to see the original U2750 removed from the bad 7A26 installed in the working 7A26, and verify that it works there. [remainder of quote deleted] |
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Re: Digitizer on eBay
Stan or Patricia Griffiths
ghpicard wrote:
--- In TekScopes@y..., "Miroslav Pokorni" <mpokorni2000@y...> wrote:I think the "damage" was more likely either the equipment was "hot" withI believe that those digitizers were used to measure all sorts ofparametersduring test, so a number of them was consumed for a single test. Myremember radiation and had to be buried with the other "hot" residue or it was actually melted down from the heat of the blast. To acquire some of this fast data, you needed to be REAL CLOSE to the source of the signals, like right right on top of it . . . Stan w7ni@... |
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Re: On screen display and other CRT items....
Dear John,
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I think that overriding concern was preserving MCP, which even overshadowed concern for phosphor. It appears that brightness setting is significant factor in time out. I seem to remember reading that shutdown is forced after so many Coulombs (ampere-seconds) of beam. The whole scope is processor controlled, so it might be pretty tough to fool it. A possibility is to fudge beam current sense, but that might effect intensity setting control and certainly would jeopardize MCP. It makes me dizzy to even think of the price of replacement CRT for that scope. It seems to me that better way would be to learn what parameters effect time out and work with it or around it. In years that I worked with one of those there were times when it did just fine and than it would get temperamental (or it was me who would forget to set it right). Fact is, I never spent time to find out what is right setting, I just kept pushing this Beam Finding button, to reset time out. However, if you find a way, please let me know. I have one and do not have manual yet and I guess I do not have guts to attack that shutdown, though it annoyed me almost to the limit of my patience. Regards Miroslav Pokorni ----- Original Message -----
From: "John Miles" <jmiles@...> To: <TekScopes@...> Sent: Tuesday, January 22, 2002 8:30 PM Subject: Re: [TekScopes] On screen display and other CRT items.... On this topic, does anyone know how to disable the "screen saver" featurejust as you're about to read it. Why in the world didn't they make theforgot 'whatthat scope was in single shot and spent some time trying to find out is wrong with my scope', but I still think that is a better way, becauseyoudo not have to mess up any settings. |
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Anybody need these Tek tubes?
wshawlee2
Recent comments about Tek matched tubes reminded me I had some
stashed away, and sure enough after a look, I have these new boxed factory Tek tubes: matched pair: 6AK5 157-0063-00 individual tubes: 2 ea. 6AL5, 154-0016-00 3 ea. 6AK5, 157-0002-00 20 ea. 8136, 154-0367-00 also have these new boxed, but not from Tek tubes: 5 ea. GE JG-12AU6 (all same batch) 5 ea. GTE/SYL. 5642 (min. HV rectifiers) happy to send them off cheaply to anybody that can use them, or swap for other Tek bits. I don't work on any more 500 series scopes, so these are looking for new homes. we do have some Tek CRTs for those older scopes too, both 3 and 5 inch, if you need them. all the best, walter |
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Re: Who's up to some remote troubleshooting?
Stan or Patricia Griffiths
Hi Lynn,
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I'll be the first to admit I don't know much about troubleshooting stuff with IC's in it but here is what I would do, if it were mine, and I had the stuff that you have. It sure sounds like U2750 to me . . . and to you too, because you have replaced it twice with no luck. To be certain it is not U2750, I would like to see the original U2750 removed from the bad 7A26 installed in the working 7A26, and verify that it works there. I always worry that something might be blowing every U2750 that I plug into the bad 7A26. If that were the case, you could indeed change U2750 twice and still not get the 7A26 to work properly . . . and you would have 3 bad IC's after that. I would want to see those IC's work in a good 7A26. The next thing I would do is check to make sure the power supplies and grounds are getting to U2750. Could be a bad IC socket. Just a couple of ideas . . . Stan w7ni@... Lynn Lewis wrote: Knowns: |
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Re: Question about 7603
Stan or Patricia Griffiths
Michael wrote:
I don't think that is quite correct. I can't argue with the reliability orIs the 7603 supposed to light up the buttons on the plug-ins? Some of mybut difficulty in changing them, but I think later mainframes like the 7904A had lit plugin lights. The reason the 7603 does not is because the power supply can't supply enough power to light them all and still regulate properly down to low line voltage. The 040-0686-01 kit that we have been discussing provides plugin lamp power in the 7603 and other 7600 series mainframes but warns about low line voltage regulation and also mainfram ambient temperature derating. So you CAN get the 7603 to provide plugin lamp power, with some limitations . . . Stan w7ni@... |
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Re: On screen display and other CRT items....
John Miles
On this topic, does anyone know how to disable the "screen saver" feature
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that blanks the 2467's BrightEye CRT after about 3 seconds? (exaggerating for effect, but sometimes it almost seems that quick.) It's very annoying, not to mention dangerous, to manuever a probe into a delicate, cramped position and have your scope go into "shutdown" mode just as you're about to read it. Why in the world didn't they make the screen-saver timer reset itself at each incoming trigger event? What was Tek thinking? -- jm ----- Original Message -----
From: "Miroslav Pokorni" <mpokorni2000@...> To: <TekScopes@...> Sent: Tuesday, January 22, 2002 3:23 PM Subject: Re: [TekScopes] On screen display and other CRT items.... Don,you do not have to mess up any settings. |
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Re: Who's up to some remote troubleshooting?
Lynn Lewis
I'm ashamed to admit I have not checked that. Will do so in the A.M.
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Thanks. Lynn -----Original Message-----
From: Miroslav Pokorni [mailto:mpokorni2000@...] Sent: Tuesday, January 22, 2002 4:56 PM To: TekScopes@... Subject: Re: [TekScopes] Who's up to some remote troubleshooting? Hello Lynn, How about Trigger Source Selector (or whatever is name of that mux controlled by a rotary switch) being stuck to Channel A. I think that the selector proper are two ICs that get alternatively disabled by a voltage input; that might be even broken wire (or trace) coming from the rotary switch, so select input is in default position. Regards Miroslav Pokorni |
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Re: On screen display and other CRT items....
I was initially surprised by the 40-80Kh number also. The difference I think
is that in a scope the tube is not driven as often (duty factor) or as hard (especially white background applications) as a CRT is in a raster scan application. Therefore I would expect digital scopes using raster CRT displays to have shorter lives than analog scopes or, say, 2400 series digital scopes which vector write an analog scope type CRT. In CRT raster scan applications, I would agree with 10Kh though they seem to last a lot longer now than 10-15 years ago. Remember those old 12" monochrome CRT monitors for PC use in the early 1980's (e.g. for HP80 series desktop computers)? If we left those greenscreens on 24/7 on our burn-in systems, they'd be toast in a year. After the first wave had to be replaced, the production operators would turn them down at night before they went home, and left them down whenever they did not have to see the display. In later years (the systems ran 17 years I'm proud to say), we couldn't even find replacement "NTSC sorta" analog input monitors. And how about those EGA color displays from around 1990?--tubes went fuzzy fast with Windows applications. We had a whole room of the things with bad tubes (and also broken electronics). Of course it didn't help that people ran, ahem, "screen saver" pictures on them when not in use. If the scope CRT number is truly closer to 10Kh there would be a lot more junk scopes around our operation, as most are left on in production, through two shifts, 5+ days a week, in auto sweep mode (with the brightness turned up too high to boot). To the best of my knowledge, we've never pulled a CRT in any of the scopes, and most of those go back more than 10 years (including a couple Tek 465Bs, Leader 100Mhz dual trace, a couple Tek 2200 series). Any more we would junk them for whatever cause if they failed--I have two I got that way. One (465B) I restored and the other (TAS465) I haven't found a service manual for yet. Both have good CRTs though. The only dim scope tube is in our trusty 571 (bought from Tucker many moons ago) which exhibits the double peaking on the intensity control that others have mentioned. The trace is pretty dim when cold, though improves with a good warmup. I watch it closely to make sure nobody just leaves it running. Quite frankly, I don't think there is anyone left besides me that can run it anyway so it is in a way "out to pasture". I've wondered if a replacement CRT is available for them from anybody.... Don |
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Re: Digitizer on eBay
Gaston,
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The EMP is a very wild beast. One of the first tests where effects were to be measured was a test named Starfish. It fired a bomb about 200 miles above Johnson Island (do not know how far on the side). As result, parts of Hawaii lost electricity and no one expected that. A nuclear caused EMP is always associated with high altitude shots. I am not sure, but it looks like lack of atmosphere is important, possibly not to attenuate charged particle flux. I do not think that any of Nevada tests had significant EMP, most of them were underground. My understanding was that instruments were physically destroyed, through shock. I guess, thumper in the hole bought time to transmit out data. Regards Miroslav Pokorni ----- Original Message -----
From: "ghpicard" <ghpicard@...> To: <TekScopes@...> Sent: Tuesday, January 22, 2002 6:52 AM Subject: [TekScopes] Re: Digitizer on eBay --- In TekScopes@y..., "Miroslav Pokorni" <mpokorni2000@y...> wrote:I believe that those digitizers were used to measure all sorts ofparametersduring test, so a number of them was consumed for a single test. Myremember |
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Re: I found a nice 7CT1N :-)!
Jose and Richard,
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When you start working on those 7D01, do not forget that cheap IC sockets were used in them. Reseating ICs does wanders for these plugs. I was burned by trying to find which IC is failing and replacing it to make it work. Then, when original IC was restored plug still worked. The character generator in DF1(2) uses ASCII for input code (that might help when finding which memory chip is not operating). If you need listing for Signetic's IC, used in DF1, I should still have it. Regards Miroslav Pokorni ----- Original Message -----
From: "Richard W. Solomon" <w1ksz@...> To: <TekScopes@...> Sent: Monday, January 21, 2002 3:07 PM Subject: RE: [TekScopes] I found a nice 7CT1N :-)! I also have one of these Plug-Ins. Now I also need to figure out how tomake it work !!am able to look at late at night listed auction items (specially those atwas not too cheap, I must admit (US$180), but it seems in perfect cosmeticCustoms to Spain and shipping is not expensive :-) |
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