Re: Odd 2247A problem, looking for insight
1/2 watt transmitter power at the right frequency gives you 1/4 watt per resistor.? If there were any snubbing diodes in the amplifier, then frequency becomes less important. Then there's likely no
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Harvey White
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#175897
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Re: Odd 2247A problem, looking for insight
some more data on this odd fault: 1. the resistor is 1/4w, fairly big to burn up. 2. when set to DC coupling, both inputs measure almost exactly 1Mohm with my 34401A. 3. vertical cal is good on the
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walter shawlee <walter2@...>
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#175896
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Re: Slightly OT: How can I dissolve Potting Compound?
As one of my profs used to say... erring on the side of caution, isn't about erring at all... it's about accessing risk, when there is a lack of scientific data. There are a lot of studies on the
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Roy Thistle
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#175895
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Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603
Hi Tom - I found the TR502 manual online, info on the crystal in the tek common parts manual (mechanical!), and a catalog page on Bliley crystal website. Whether Bliley wants to grind another? I
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J Mcvein
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#175894
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Re: Slightly OT: How can I dissolve Potting Compound?
I've been working with MEK for years with no apparent health issues. MEK is the solvent of choice for virtually al adhesives except CA and epoxies used in speaker building and repair. I do have
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Thomas Garson
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#175893
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Re: Odd 2247A problem, looking for insight
Any clue as to its provenance? Harvey's xmtr shot was the first thing that crossed my mind. One of those little resistors could go before you finished saying 'Oh sh**!' -ls-
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teamlarryohio
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#175892
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Re: Slightly OT: How can I dissolve Potting Compound?
I recall my late sister telling me 'everything in moderation'.? She was referring to food, but the same applies to solvents.? If you are involved with the stuff, do so very sparingly and you
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Bob Albert <bob91343@...>
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#175891
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
I have similar ideas, phase detection, AC and DC voltage measurement, and PNP/NPN transistor lead ID, beta, and leakage to frame.? Going to be more complicated than the existing projects because I
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Harvey White
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#175890
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Re: Slightly OT: How can I dissolve Potting Compound?
I figured that I would probably elicit an over reactive response from you, Roy. To those not familiar with handling chemicals dangerous to one¡¯s health it is better to be more safe than sorry. If
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Greg Muir
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#175889
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Re: Slightly OT: How can I dissolve Potting Compound?
Dennis, Can't help much on the spectral tube side of things, but I used to work in thick film hybrids many moons ago where we had to occasionally 'de-pot' circuits. One of the few things which will
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Jon Scott
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#175888
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Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603
Hi Jim, Very interesting -- could you post a link to where you found that information? Thanks! -- Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA
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Tom Lee
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#175887
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Re: 2230 storage deja vu
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Bert Haskins
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#175886
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
I have also thought about a TM500 tester that included: - Presence/absence (but not correctness or ripple) of each of the supply voltages - Brought out all supplies to banana jacks for metering and
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Andy Warner
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#175885
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Re: Slightly OT: How can I dissolve Potting Compound?
MEK is not MEKP... and MEK is not known to be toxic to the liver. Acetone is not as "bad" (whatever that means) as MEK... and acetone is present in the human body, and disposed by it, during normal
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Roy Thistle
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#175884
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Re: Odd 2247A problem, looking for insight
Let's see, 62 ohm resistor (that feels like a 1/10 watt just to start), input capacitance of some sort (20 pf, but you'd think that wouldn't be much), feed the scope RF.? 27 Mhz, 20pf gives about 294
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Harvey White
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#175883
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Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603
Thank you so much Jim, therefore your 52.5 MHz crystal cannot be used to convert the TR503 to TR502. Patience I will try to find a TR502. I thank you for the help you have given me. --Cheers Attilio
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Attilio
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#175882
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
I see no significant advantage to a group purchase of the wafer switch for this tester. DigiKey has 100+ available and the discount for a quantity purchase is not that much. Further, it is likely that
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Larry McDavid
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#175881
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Re: Peter Keller's Book Mailing Status (Minor Correction)
My many thanks to Dennis for a job well done. From a PhD in EE, I want to thank you for all the work that you have done. I will think of you and your efforts when I read and enjoy his book!! Marvin
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Marvin Moss
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#175880
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Colin, I don't know a cost yet for the board set and I am not sure I can get an accurate estimate of shipping to the UK. My experience shipping to Europe is that it cost a *lot* more than our domestic
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Larry McDavid
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#175879
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Re: Odd 2247A problem, looking for insight
Walter, I suppose it is possible that U112 has beefy input protection (diode clamps to the supplies?) that might survive enough current to burn a small 62 ohm resistor. At maximum sensitivity the
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John Gord
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#175878
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