Re: Provenance of your vintage gear
I have a fair number of items with asset tags from SRI, Lawrence Livermore, Ampex, Nasa, etc.? I really hate tags all over front panels, and usually remove them, but will leave them if they are
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Dave Seiter
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#180083
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Re: Provenance of your vintage gear
I bought a 547 from a retired Radio Canada tech sometime in the early 90s. I think it was either because Don Lancaster mentioned these old scopes or I bought the 547 then I read about the 500
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Snappy
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#180082
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Re: Restoring CRT emission?
Speaking of BeO Tektronix used BeO substrates in some of the power hybrids. Specifically the gold plated TO8 packages with the heat sink post on the bottom. The substrates came pre-scribed in a sheet
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Craig
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#180081
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Re: [Tek 485] No intensity control
Yes, I also see 2N3565 as the cross reference. This transistor may be difficult to find, you can start replacing diodes and the capacitor first. If it still doesn't fix the issue, and you can't find
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Ozan
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#180080
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Analog video animation (Not related yet interesting)
Applying special effects to video using analog circuitry, no digital processors required David Sieg - Introduction to the scanimate part 1 https://www.youtube.com/watch?v=UHjkMThH0aE
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DW
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#180079
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Re: Restoring CRT emission?
Radiation is a bugaboo for many folks. Think of it this way, a little bitty birthday candle emits photons. It will scarcely light a room, leaving the edges dark. You can burn yourself, but don't count
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Chuck Harris <cfharris@...>
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#180078
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Re: Provenance of your vintage gear
I have a lot of interesting property tags on stuff, from all over. Naval Underwater Systems Center (doesn't exist anymore, absorbed into something else), LANL, Sandia, Boeing, IBM, Bendix Kansas City
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Sean Turner
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#180077
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Re: Restoring CRT emission?
A thoriated tungsten cathode will glow bright yellow. It gives an incandescent light bulb a run for its money. Nobody wants that in a radio tube. So, barium and strontium ceramics are used to get even
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Chuck Harris <cfharris@...>
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#180076
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Re: 1S1 on ebay
Anyone got a link for this mod? Schematic?
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Snappy
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#180075
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Re: 3T77 tunnel diodes (again)
Well... I tried it, and made things worse (risetime ~ 3 ns, fall ~ 5 ns)! After some tweaking of pullup R and a shunt capacitor on the resistor to the PNP base, the waveform at the trimpot/TD has
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Charles, WB3JOK/0
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#180074
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7M13 buttons
Just acquired a working 7M13 but the C and H buttons are broken. The 10-way button assembly doesn't have a Tek part number in the manual, it is just listed as an assembly. Is there any source for it?
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EJP
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#180073
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Re: Provenance of your vintage gear
My interest in vintage Tek gear comes from my first two scopes, which belonged to my father: a 475 from his time working as a service engineer for Varian MAT, and a 2213 that he bought when he went
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Jeff Dutky
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#180072
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Re: To Beeswax or not to Beeswax: that is the question.
I'm pretty sure that at least for non-high voltage transformers, Tek used a black polyurethane varnish for impregnation. I recall long ago, I picked up a couple of expired gallon cans at the Country
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Ed Breya
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#180071
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Re: Restoring CRT emission?
Steve, you may be thinking of beryllium alloyed with magnesium. Many structural and precision mechanical parts were made with Be in the old days, for light weight and strength. Be particles can be
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Ed Breya
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#180070
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Re: To Beeswax or not to Beeswax: that is the question.
Glyptol was a General Electric product. It was used extensively for motor and transformer windings, and did it's job very well. Otis Elevator used it for general painting of car frames, machine
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greenboxmaven
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#180069
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Re: Restoring CRT emission?
Unbroken, the vacuum tubes with thoriated cathodes would not be a problem. The government made things worse by having them smashed. But the government also sold off Bomarc Missile surplus years ago
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stevenhorii
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#180068
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Re: Restoring CRT emission?
Chuck is absolutely right. The amount of thorium in a cathode is vanishingly small ¡ª it is used to lower the work function at the surface of the tungsten, and is typically present in concentrations
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Tom Lee
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#180067
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Provenance of your vintage gear
So, I am a new member and maybe this topic been discussed before.... I recently was trying to use a 1A1 plugin in my 1956 type 531... Have some issues with it.... Reason for joining. While I was
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Pwrelectronics
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#180066
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Re: How to troubleshoot a faulty 7B50 timebase
Q784 and Q794 form an emitter coupled differential amplifier. Put a signal in on the base of Q784 and you should see a signal on the collector of Q784 and the inverted signal on Q794. It looks as if
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Harvey White
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#180065
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Re: 3T77 tunnel diodes (again)
How about adding a PNP switching transistor... emitter to +5, base driven from the TTL output, and collector to the trimpot/TD? That way the +5 supply stays negative-ground, and the TD continues to
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Charles, WB3JOK/0
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#180064
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