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Re: 7854 waveform calculator on eBay
Craig Sawyers
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I 'm surprised at how much these go for, considering it's basically just a keyboard. I remember back in the late '70s when the local computer store was selling keyboards for about $150. A few years later they became a cheap commodity. My entire 7854 system (except for the 7b87) cost me $125. -dave ========================================= I too am surprised. In fact I considered building one - it is after all just a switch matrix with some data buffers to return row and column to the mainframe. But to purchase the tactile switches and buttons would have been 90% of the cost of buying one. Dave - when did you manage to get the snip of $125? I have a bunch of tales of things I bought for a few dollars (NIB 7623B for $100, AA501 for $14, A 7L5 with tracking generator for ?70 including mainframe, 575 for ?40, a whole load of sampling gear for hardly anything) - but these days are a misty recollection, and the days of cheapo stuff seem to be a thing of the past - unless you live in California with all sorts of wonderful swap meets and surplus stores. Craig |
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Re: Curve Tracer Test Temperature, Was Wanted: 7CT1N Curve Tracer Plug-In
Don Black
开云体育Hi David, do you have a link to the circuit using the LM389 please, I'd like to see how it's used.Thanks, Don Black. On 23-Mar-13 4:21 AM, David wrote: ? |
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Re: Anti-static bags
On Fri, Mar 22, 2013 at 2:32 PM, Dave Daniel <kc0wjn@...> wrote:
Does anyone have a preferential source for anti-static bags? I can findYou probably want metallic ESD bags, not pink poly antistatic bags. For small quantities, I can recommend: Courtney Farr CKC Computers eBay seller cfarrkc For larger quantities try: If you don't care about ziplock seals, you can save money on small bags by buying large bags and a bag sealer. I haven't found any bargains on ESD bags on eBay, but it's a good place to get a bag sealer. |
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7L12 first mixer
My 7L12 arrived from Sphere's today, fast shipping and very well
packaged, and it's in great condition considering it's maybe 40 years old. Thank you ever so much Walter. Walter's diagnosis was spot on, there was a problem with the 1st mixer, Tek 119-0130-00 which happens to be a RELCOM M11H-1. The connectors look to be in good shape and a little pressure on the rigid going into the mixer brings the mixer loss back up to what it should be, give or take a few dBs perhaps, calibrator output now shows up as -30dBm :-) Good news, the diodes aren't fried but I suspect there is a dry joint on the RF port (IF out) inside the mixer. I guess 40 years of thermal cycling is going to produce a few dry joints here and there. I could either try to repair the dry joint or replace the mixer. A repair would involve removing the case but I don't know what's inside, so if anyone has ever taken one of these mixers apart a picture or description would nice. If I could take it apart without damaging anything I could always get a new case made. The second option would be a drop in replacement. If anyone has a datasheet for a RELCOM M11H-1 it would be greatly appreciated. For now I will just have to gently prod a few rigid cables now and then. Best regards Chris |
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Re: Tektronix Programmed Semiconductor Instruction Materials
Yes that appears to be them. I corrected the link slightly to:
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And there is a lot of interesting stuff there. Thanks a lot. Phil... --- In TekScopes@..., Dave Daniel <kc0wjn@...> wrote:
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Re: Tektronix Programmed Semiconductor Instruction Materials
开云体育It's amazing what is available out there. Many people have gone to the trouble of preserving these types of documents.It always amuses me to find an item on eBay that one can down load for free, paticulkarly when the item on eBay is only on digital media. Dave On 3/22/2013 6:45 PM, Tom Jobe wrote:
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Re: Handy hint for a screen filter
keithostertag
I don't know if it is still true, but years ago Rosco would send you, free, little sample books with 1x3 inch samples of all their gels in the mail. If they still do that, you could use the samples to test out which one works for your situation. You might look them up on the web to see if they still send out those free sample books. If you have a friendly local photo store nearby they might have them to hand out as well.
There might also be other sources as well- I haven't looked in to it for years. There are other brands- Rosco being one of the top- which means greater selection and generally slightly higher pricing. Keith Ostertag |
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Re: Tektronix Programmed Semiconductor Instruction Materials
Tom Jobe
开云体育Thanks Dave!
I downloaded that whole series of free?Tektronix
Semiconductor books from your link and they are very?nice!
There is a lot of other good stuff on that web site
too.
It is amazing how much good, freely available,?stuff is
for sale on eBay!
tom jobe...
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Re: Tektronix Programmed Semiconductor Instruction Materials
开云体育I believe the VintageTEK Museum () is in the process of scanning ALL of the Tek Programmed Instruction Series. This includes the Basic Electrical Theory, Semiconductor Diodes and Transistors, Time Domain Reflectrometry, and Spectrum Analysis volumes. ? If any of you are in the Portland area it is definitely worth a visit to the museum. Their collection is growing by leaps and bounds and they are now selling excess (Tek and other) equipment at reasonable prices on their web site. ? Volunteers are needed, and I speak from firsthand experience that as a volunteer you will meet some of the legendary designers at Tek. ? Dennis |
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Re: 7854 waveform calculator on eBay
Not in any hurry to sell my 7854 or keyboard, paid about $500
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for it 10 years ago, and then a lot on top of that to ship it to the UK. They're great scopes and mine's outlived a 465 and a 475. I saw one 7L5 going for $1600 recently and another 7L5 going for $2200. YOu could probably get a 3585 for that !! Chris --- In TekScopes@..., Peter Gottlieb <hpnpilot@...> wrote:
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Re: Curve Tracer Test Temperature, Was Wanted: 7CT1N Curve Tracer Plug-In
Gordon
On 22/03/2013 23:03, David wrote:
I think you could still do it with a curve tracer that does notI wasn't after the optimal bias/temp point, Dennis brought that up. I just wanted to measure Idss and get the same result whatever the ambient temperature was. And preferably in line with the manufacturers data. [...] Look up "delta Vbe temperature" on Google.AN45 to save anyone looking. Very interesting. Thanks. Gordon |
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Re: Curve Tracer Test Temperature, Was Wanted: 7CT1N Curve Tracer Plug-In
The important consideration for the 7CT1N and 5CT1N is cost, not capability.
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No one at Tek thought that these two units were ever a substitute for a full function curve tracer. A 5CT1N and a 5000 series scope was the cheapest Tek curve tracer you could buy, and if all you needed was a family of curves, it was a reasonable solution. Likewise, if your company already owned a 7000 MF, as most did, a 7CT1N was the cheapest way to add curve tracer capability. Many engineers are uncomfortable with the 575/576/577 because they don't use them often enough. For those engineers the 5CT1N / 7CT1N must have been easier to deal with. If what I saw in my career is any indication most engineers don't know how to use more than 1% of all the things a curve tracer can do for them. The 575 taught me more semiconductor theory than all of my college professors combined. With my 577 I continue to learn new things that curve tracers can do with all sorts of active and passive devices. I still don't think I have used more than 40% of what it can do. Dennis -----Original Message-----
From: David Sent: Friday, March 22, 2013 4:03 PM On Fri, 22 Mar 2013 19:48:14 +0000, Gordon <tekscopes@...> wrote: <snip> I agree with Walter's earlier post that the 7CT1N is a lessor curve tracer. I believe its popularity just comes from being a 7000 series plug-in. If the 5000 series had been more popular than the 7000 series, then Walter from Sphere would have said something about how overrated the 5CT1 is instead. :) |
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Re: Tektronix Programmed Semiconductor Instruction Materials
开云体育Looks like these are available in PDF form at , along with some other cool stuff.DaveD On 3/22/2013 5:30 PM, Tom Jobe wrote:
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Re: Tektronix Programmed Semiconductor Instruction Materials
Tom Jobe
开云体育I saw the earlier?post about this series of books from
Tektronix.
I have an original copy of the volume titled "Semiconductor
Diodes and Transistors programmed Instruction Volume 7, reference for Volumes 4
and 5". It has part number 062-0432-00 on the front of it and it is dated March
of 1969. Obviously there are a number of other volumes in this
series.
If there isn't a free copy of this volume available, I will be
happy to scan its 227(?) pages into a PDF file and post it to
KO4BB.com.
tom jobe...
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Re: AVR Transistor Tester
-Dave
Dennis 4??? like 321092713011? newer software with more functions SMT AVR chip probably difficult to replace, upgrade.
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Re: 7854 waveform calculator on eBay
Peter Gottlieb
Wow if that's what they're going for maybe I should sell my 7854 and keyboard separately!
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I am getting around to selling that and some others off, and it's a nice, fully working unit, which seems to be getting rarer and rarer. Didn't get it for $125 though... On 3/22/2013 7:08 PM, d.seiter@... wrote:
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Re: Anti-static bags
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Re: Handy hint for a screen filter
Rob
开云体育If there was a “useful answer button” Anad’s answer would get high honor from me. I had asked a similar question as the original poster some 6 months ago. The Gelpaper solution was pointed out then (I cannot find the message thread for some reason so Thank you Anad for this time and back then…as well) ? As it turns out there is such a selection of colors and densities. I have not settled on which ones I like best. I have order from the following link: There are several other suppliers as well. Do any on the forum have specific vendors and colors they have found? Experimenting has been kind-of fun and I have found a couple of ‘ok’ colors (but the density is to light for my sensibilities). ? If anyone has ran down there favorite I sure would appreciate it if you could share. I am looking for a good green (for 7000 series storage scopes) and a good blue for the same series of scopes. Is there a preferred color? I haven’t seen any others but blue and green for 7000 series were others offered? ? Thanks as always for the bandwidth. Rob ? From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Anad SivolcSP
Sent: Friday, March 22, 2013 4:45 PM To: TekScopes@... Subject: [TekScopes] Re: Handy hint for a screen filter ? ? Your local music store has "Gelpaper",which is their term for heat-resistant Color Filtering sheets used on those huge multicolored lighting arrays. Comes in all colors and graduations of colors And densities..Take your scope..some crts filter differently than you might think,as there are different green color temps and purities. Some filter blue beautifully, others refuse to and appear a? sickly green thru the blue. Apparently some phosphors are a? purer green .With the graduations available, you may find one that works much better than another,even tho they look similar, and the density graduations let you find one you can still see the graticule thru without running a scary intensity level.. d: )> ? |
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Re: 7854 waveform calculator on eBay
I 'm surprised at how much these go for, considering it's basically just a keyboard.?I remember back in the late '70s when the local computer store was selling keyboards for about $150.? A few years later they became a cheap commodity. ? ?My entire 7854 system (except for the 7b87)?cost me?$125.? ? -dave
From: "David Holland"
To: TekScopes@... Sent: Friday, March 22, 2013 12:52:28 PM Subject: Re: [TekScopes] 7854 waveform calculator on eBay ? IIRC, there's little aluminum pegs/stand offs that the circuit board |
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WTB - 7L13 or 7L14 Center Frequency Knob
Does anyone have a spare center frequency knob (grey with black inlay) for sale? It come with a brass weight insert but I have the brass part and only need the plastic knob part. I was about to put my otherwise perfect 7L14 up for sale and noticed a crack in the knob and it fragmented on removal. The brass weight insert has a 1/8" diameter shaft.
thanks Jerry K1JOS |